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carbon-lang/toolchain/benchmarking/source_gen.cpp
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Chandler Carruth 5aa7f35a1f Add another C++ keyword we need to avoid (#8015) 
The enhancements to benchmarking means we can (when _very_ unlucky) hit
this now.
2026-10-22 13:22:12 +00:00

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// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "toolchain/benchmarking/source_gen.h"
#include <algorithm>
#include <array>
#include <cmath>
#include <numbers>
#include <numeric>
#include <string>
#include <utility>
#include "absl/random/seed_sequences.h"
#include "common/raw_string_ostream.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Sequence.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/FormatVariadic.h"
#include "toolchain/lex/token_kind.h"
namespace Carbon::Testing {
auto SourceGen::Global() -> SourceGen& {
static SourceGen global_gen;
return global_gen;
}
SourceGen::SourceGen(Language language) : language_(language) {}
// Heuristic numbers used in synthesizing various identifier sequences.
static constexpr int MinClassNameLength = 5;
static constexpr int MinMemberNameLength = 4;
// The length of every local variable name. How many times a definition spells
// each local depends on the local's position, so a single length keeps the byte
// count from depending on which name lands where. Locals are shorter than class
// names, so they can't shadow a class that the definition names. This is
// hard-coded rather than in `ClassParams` because seed-independent output sizes
// require a single length `< MinClassNameLength`; it would only need to be
// parameterized to benchmark identifier-length sensitivity specifically for
// local variables.
static constexpr int LocalNameLength = 3;
// The number of function and method declarations in each class.
static auto NumDeclsPerClass(const SourceGen::ClassParams& params) -> int {
return params.public_function_decls + params.public_method_decls +
params.private_function_decls + params.private_method_decls;
}
// The number of inline definitions of every kind in each class.
static auto NumInlineDefsPerClass(const SourceGen::ClassParams& params) -> int {
return params.inline_function_defs + params.inline_getters +
params.inline_predicates + params.inline_forwarders;
}
// Returns the fixed types that satisfy `eligible`, each repeated `weight` times
// and interleaved with the others.
static auto WeightedFixedTypes(
const SourceGen::TypeUseParams& params,
llvm::function_ref<
auto(const SourceGen::TypeUseParams::FixedTypeWeight&)->bool>
eligible)
-> llvm::SmallVector<const SourceGen::TypeUseParams::FixedTypeWeight*> {
llvm::SmallVector<const SourceGen::TypeUseParams::FixedTypeWeight*> weighted;
for (int round = 0;; ++round) {
int size = weighted.size();
for (const auto& fw : params.fixed_type_weights) {
if (fw.weight > round && eligible(fw)) {
weighted.push_back(&fw);
}
}
if (static_cast<int>(weighted.size()) == size) {
return weighted;
}
}
}
// The kinds of statement in a definition plan. A plan fixes how many statements
// of each kind a definition has at each depth of nesting, and the definition
// arranges them randomly. A statement has the same size wherever it lands at
// its depth, so the arrangement doesn't change the definition's size.
//
// TODO: Plans only declare and update `i32` locals, read each parameter once,
// and make no calls. Real definitions have locals of many types, read
// parameters and fields throughout, and make calls in most statements. Add
// those statements and expressions, fixing each one's spelling before the
// shuffle as the type use pools do, so that sizes stay the same for every seed.
enum class PlanKind : uint8_t {
// `var <local>: i32 = <expr>;`
Local,
// `<local> = <expr>;`
Update,
// `if (<cond>) {`, a block, and `}`.
If,
// `if (<cond>) {`, a block, `} else {`, a block, and `}`.
IfElse,
// `if (<cond>) {`, a block, `} else if (<cond>) {`, a block, and `}`.
ElseIf,
// `while (<cond>) {`, a block, and `}`.
While,
// `if (<cond>) {`, `return <value>;`, and `}`.
GuardReturn,
// `if (<cond>) {`, `break;` or `continue;`, and `}`, in a loop's block.
GuardExit,
// `<local> = <local> + <reads>;`, where the reads apply a consumer template
// to each parameter, and read `self` in a method. Definitions add one of
// these to their plan's statements at depth 0.
ReadParams,
};
static constexpr int NumPlanKinds = static_cast<int>(PlanKind::ReadParams) + 1;
// The number of blocks that a statement of `kind` opens.
static auto NumPlanBlocks(PlanKind kind) -> int {
switch (kind) {
case PlanKind::If:
case PlanKind::While:
return 1;
case PlanKind::IfElse:
case PlanKind::ElseIf:
return 2;
default:
return 0;
}
}
// A statement in a definition plan. `spelling_index` selects among the
// available spellings for `kind`, in `[0, NumPlanSpellings(kind))`.
struct PlanStmt {
PlanKind kind;
int spelling_index;
};
// The expressions and conditions in plan statements. `{0}` and `{1}` are
// locals, which all have the same length. Conditions compare a single local, so
// that they can't compare a local with itself.
static constexpr llvm::StringLiteral PlanExprs[] = {
"{0} + 1", "{0} * 2", "{0} - {1}", "({0} % 7) + {1}"};
static constexpr llvm::StringLiteral PlanConds[] = {"{0} > 3", "{0} < 9",
"{0} == 2", "{0} != 5"};
// The number of distinct spellings for a statement of `kind`.
static auto NumPlanSpellings(PlanKind kind) -> int {
switch (kind) {
case PlanKind::Local:
case PlanKind::Update:
return std::size(PlanExprs);
case PlanKind::If:
case PlanKind::IfElse:
case PlanKind::ElseIf:
case PlanKind::While:
case PlanKind::GuardReturn:
return std::size(PlanConds);
case PlanKind::GuardExit:
// Pairs one of `PlanConds` with `break;` or `continue;`.
return std::lcm<int>(std::size(PlanConds), 2);
case PlanKind::ReadParams:
return 1;
}
}
// The statements of a definition plan at each depth. The statement that a guard
// returns or exits with is one depth below the guard, and isn't listed.
struct DefPlan {
llvm::SmallVector<llvm::SmallVector<PlanStmt>> levels;
// The number of lines and locals in the plan's statements.
int lines = 0;
int locals = 0;
};
// The internal shape calibration of definition plans, which approximates the
// function definitions in a sample of the Carbon toolchain's, LLVM's, and
// Clang's implementation files, as classified with libclang (excluding
// definitions with a `switch`).
//
// These constants are hardcoded rather than in `DenseDeclParams` or
// `ClassParams` unless a benchmark or test needs to vary a specific structural
// dimension inside definitions (such as nesting depth, branching factor, or
// local variable density) independently of statement count.
//
// All rates and bucket distributions below are integer percentages (with
// multi-bucket rows summing to 100).
//
// A row of `PlanShapeTable` giving the shape parameters for plans with at
// least `min_statements` statements: the percentage of plans with each maximum
// depth, and the number of guard returns at a depth as a percentage of the
// statements at the next depth.
struct PlanShapeRow {
int min_statements;
std::array<int, 6> max_depth_percents;
int guard_return_percent;
};
// Rows are sorted in strictly increasing order of `min_statements`, starting
// with `min_statements = 0` so that every statement count has an applicable
// row. A plan deterministically uses the last row with
// `min_statements <= statements`.
static constexpr PlanShapeRow PlanShapeTable[] = {
{.min_statements = 0,
.max_depth_percents = {100, 0, 0, 0, 0, 0},
.guard_return_percent = 0},
{.min_statements = 2,
.max_depth_percents = {25, 62, 13, 0, 0, 0},
.guard_return_percent = 65},
{.min_statements = 5,
.max_depth_percents = {8, 64, 25, 3, 0, 0},
.guard_return_percent = 47},
{.min_statements = 8,
.max_depth_percents = {7, 46, 34, 11, 2, 0},
.guard_return_percent = 32},
{.min_statements = 13,
.max_depth_percents = {2, 36, 39, 18, 4, 1},
.guard_return_percent = 21},
{.min_statements = 20,
.max_depth_percents = {2, 21, 42, 25, 7, 3},
.guard_return_percent = 16},
{.min_statements = 29,
.max_depth_percents = {0, 11, 32, 35, 17, 5},
.guard_return_percent = 12},
{.min_statements = 43,
.max_depth_percents = {0, 2, 23, 42, 21, 12},
.guard_return_percent = 10},
{.min_statements = 67,
.max_depth_percents = {0, 5, 4, 29, 30, 32},
.guard_return_percent = 12},
};
// Indexed by a plan's maximum depth, each row gives the percentage of the
// plan's statements at each depth (summing to 100). Every definition also has
// three statements at depth 0, so plans have a lower share there than real
// definitions.
static constexpr std::array<int, 6> PlanDepthPercents[] = {
{100, 0, 0, 0, 0, 0}, {60, 40, 0, 0, 0, 0}, {38, 45, 17, 0, 0, 0},
{25, 38, 27, 10, 0, 0}, {17, 29, 28, 18, 8, 0}, {13, 25, 24, 19, 13, 6},
};
// The percentage of loop blocks that have a guard exit (`break` or `continue`).
static constexpr int LoopExitPercent = 35;
// The percentage of non-guard statements at the next depth that open a new
// `if`, `else`, or `while` block (~2.1 statements per block).
static constexpr int NewBlockPercent = 48;
// The percentages of those blocks that are a loop's, and that are one of the
// two blocks of an `if` with an `else` or `else if`.
static constexpr int LoopBlockPercent = 15;
static constexpr int ElseBlockPercent = 30;
// The percentage of those two-block `if` statements that use `else if` rather
// than `else`.
static constexpr int ElseIfPercent = 42;
// How many times more likely a loop block is than another block of the same
// size to get each further statement when arranging a definition.
static constexpr int LoopBlockWeight = 3;
// The percentages of the statements at depth 0, and deeper, that declare a new
// local variable.
static constexpr int TopLocalPercent = 35;
static constexpr int NestedLocalPercent = 25;
// Scales `count` by `percent`%, rounding up with probability equal to the
// remainder (`(count * percent % 100) / 100.0`).
using ScaleByPercentFn = llvm::function_ref<auto(int count, int percent)->int>;
// Returns the maximum depth of the `variant`th plan with `statements`
// statements. The variants of a size follow the distribution in its row of
// `PlanShapeTable`: multiples of the golden ratio (`std::numbers::phi`) mod 1.0
// in `double` spread their choices evenly across `[0, 100)` without needing a
// fixed-point rational approximation.
static auto ChoosePlanMaxDepth(const PlanShapeRow& shape, int statements,
int variant) -> int {
int choice = static_cast<int>(
std::fmod((variant + 0.5) * std::numbers::phi, 1.0) * 100);
int max_depth = 0;
for (int percent : shape.max_depth_percents) {
choice -= percent;
if (choice < 0) {
break;
}
++max_depth;
}
return std::min(max_depth, statements - 1);
}
// Splits `statements` statements between depths 0 through `max_depth`,
// following `PlanDepthPercents` and giving each depth at least one.
static auto SplitPlanDepths(int statements, int max_depth,
ScaleByPercentFn scale_by_percent)
-> llvm::SmallVector<int> {
llvm::SmallVector<int> depth_counts;
int cumulative_percent = 0;
int assigned = 0;
for (int percent :
llvm::ArrayRef(PlanDepthPercents[max_depth]).take_front(max_depth)) {
cumulative_percent += percent;
int upto = scale_by_percent(statements, cumulative_percent);
depth_counts.push_back(upto - assigned);
assigned = upto;
}
depth_counts.push_back(statements - assigned);
for (int& count : depth_counts) {
if (count == 0) {
++count;
--*llvm::max_element(depth_counts);
}
}
return depth_counts;
}
// Composes the plan of a definition with `statements` statements, for the
// `variant`th definition of that size. Percentage-scaled counts round with a
// generator seeded with the size and variant, so that definitions of one size
// vary while their average follows the calibration, and nothing depends on the
// `SourceGen` seed.
static auto ComposeDefPlan(int statements, int variant) -> DefPlan {
DefPlan plan;
if (statements == 0) {
return plan;
}
absl::SeedSeq seed_seq = {statements, variant};
absl::BitGen rng(seed_seq);
auto scale_by_percent = [&](int count, int percent) {
return (count * percent + absl::Uniform<int>(rng, 0, 100)) / 100;
};
// Find the last row satisfying `statements >= row.min_statements`. This
// invariant is satisfied for `*shape` throughout the loop because the first
// row has `min_statements == 0`.
static_assert(PlanShapeTable[0].min_statements == 0);
const PlanShapeRow* shape = PlanShapeTable;
for (const PlanShapeRow& row : PlanShapeTable) {
if (&row != PlanShapeTable) {
CARBON_CHECK(row.min_statements > (&row - 1)->min_statements);
}
if (statements >= row.min_statements) {
shape = &row;
}
}
llvm::SmallVector<int> depth_counts = SplitPlanDepths(
statements, ChoosePlanMaxDepth(*shape, statements, variant),
scale_by_percent);
plan.levels.resize(depth_counts.size());
// Select each statement's spelling starting from `variant` and advancing with
// each statement of the same kind, so that spellings rotate both across
// variants of the same size and across same-kind statements within a plan.
std::array<int, NumPlanKinds> next_spelling = {};
next_spelling.fill(variant);
auto add = [&](int depth, PlanKind kind, int count) {
int num_spellings = NumPlanSpellings(kind);
int& next = next_spelling[static_cast<int>(kind)];
for (auto _ : llvm::seq(count)) {
plan.levels[depth].push_back(
{.kind = kind, .spelling_index = next % num_spellings});
++next;
}
};
// How many of `depth_counts[depth]` are the `return`, `break`, or `continue`
// body statements of guards at `depth - 1` (which are emitted as part of
// those guards rather than as separate `PlanStmt`s at `depth`).
int guard_children = 0;
// The blocks at a depth, and how many of them are loop blocks.
int blocks = 1;
int loop_blocks = 0;
int num_depths = depth_counts.size();
for (int depth : llvm::seq(num_depths)) {
int count = depth_counts[depth];
int heads = count - guard_children;
int next = depth + 1 < num_depths ? depth_counts[depth + 1] : 0;
int guards = 0;
int exits = 0;
int ifs = 0;
int pairs = 0;
int loops = 0;
int next_blocks = 0;
if (next > 0) {
// Guards' statements can't hold deeper ones, so leave a free statement at
// the next depth when there are any.
int min_free = depth + 2 < num_depths ? 1 : 0;
exits = std::min({scale_by_percent(loop_blocks, LoopExitPercent), heads,
next - min_free});
guards = std::min({scale_by_percent(next, shape->guard_return_percent),
heads - exits, next - exits - min_free});
// The number of statements at the next depth that aren't the body of a
// guard at this depth, and so must be placed in blocks opened by
// non-guard statements at this depth.
int free = next - guards - exits;
// When there are such `free` statements at the next depth (rather than
// every statement at the next depth being a guard's body), keep at least
// one non-guard statement at this depth to open a block for them.
if (free > 0 && heads == guards + exits) {
if (guards > 0) {
--guards;
} else {
--exits;
}
++free;
}
if (free > 0) {
next_blocks = std::max(1, scale_by_percent(free, NewBlockPercent));
loops = scale_by_percent(next_blocks, LoopBlockPercent);
pairs = std::min(scale_by_percent(next_blocks, ElseBlockPercent / 2),
(next_blocks - loops) / 2);
ifs = next_blocks - loops - 2 * pairs;
// Fit the statements that open blocks into this depth, merging blocks
// when they don't fit.
int room = heads - guards - exits;
while (ifs + pairs + loops > room) {
if (ifs >= 2) {
ifs -= 2;
++pairs;
} else if (ifs > 0) {
--ifs;
--next_blocks;
} else if (loops > 0) {
--loops;
--next_blocks;
} else {
--pairs;
next_blocks -= 2;
}
}
}
}
int fixed = guards + exits + ifs + pairs + loops;
// Each block at this depth ends with a statement that isn't a local.
int max_locals = heads - fixed - std::max(0, blocks - fixed);
int local_percent = depth == 0 ? TopLocalPercent : NestedLocalPercent;
int locals = std::min(scale_by_percent(heads, local_percent), max_locals);
int else_ifs = scale_by_percent(pairs, ElseIfPercent);
add(depth, PlanKind::Local, locals);
add(depth, PlanKind::Update, heads - fixed - locals);
add(depth, PlanKind::If, ifs);
add(depth, PlanKind::IfElse, pairs - else_ifs);
add(depth, PlanKind::ElseIf, else_ifs);
add(depth, PlanKind::While, loops);
add(depth, PlanKind::GuardReturn, guards);
add(depth, PlanKind::GuardExit, exits);
// Each statement takes a line, and so does the `}` that ends each block and
// guard, and the line between the blocks of a pair.
plan.lines += count + ifs + loops + 2 * pairs + guards + exits;
plan.locals += locals;
guard_children = guards + exits;
blocks = next_blocks;
loop_blocks = loops;
}
return plan;
}
// Returns how many of `num_defs` definitions have each size in `sizes`, in
// proportion to its weight. The definitions left over from rounding down go to
// the sizes with the largest remainders, the earliest first on ties.
static auto ApportionDefSizes(int num_defs,
llvm::ArrayRef<SourceGen::DefSizeWeight> sizes)
-> llvm::SmallVector<int> {
int64_t total_weight = 0;
for (const SourceGen::DefSizeWeight& size : sizes) {
CARBON_CHECK(size.statements >= 0 && size.weight >= 0,
"Definition sizes and weights can't be negative.");
total_weight += size.weight;
}
CARBON_CHECK(total_weight > 0,
"Definition sizes need a positive total weight.");
llvm::SmallVector<int> counts;
llvm::SmallVector<int64_t> remainders;
int left_over = num_defs;
for (const SourceGen::DefSizeWeight& size : sizes) {
int64_t share = static_cast<int64_t>(num_defs) * size.weight;
counts.push_back(share / total_weight);
remainders.push_back(share % total_weight);
left_over -= counts.back();
}
llvm::SmallVector<int> order(sizes.size());
std::iota(order.begin(), order.end(), 0);
llvm::stable_sort(order, [&](int lhs, int rhs) {
return remainders[lhs] > remainders[rhs];
});
for (int index : llvm::ArrayRef(order).take_front(left_over)) {
++counts[index];
}
return counts;
}
// Builds the plans for `num_defs` definitions, with sizes following `sizes`,
// and appends them to `plans`. Each size's plans spread evenly through the
// order, so that any stretch of the order has a mix of sizes.
static auto BuildDefPlans(int num_defs,
llvm::ArrayRef<SourceGen::DefSizeWeight> sizes,
llvm::SmallVectorImpl<DefPlan>& plans) -> void {
// Entries are sorted by `position`, which is `(variant + 0.5) / count`, to
// interleave buckets with different counts.
struct Entry {
double position;
int statements;
int variant;
};
llvm::SmallVector<Entry> entries;
entries.reserve(num_defs);
llvm::SmallVector<int> counts = ApportionDefSizes(num_defs, sizes);
for (auto [size, count] : llvm::zip_equal(sizes, counts)) {
for (int variant : llvm::seq(count)) {
entries.push_back({.position = (variant + 0.5) / count,
.statements = size.statements,
.variant = variant});
}
}
llvm::stable_sort(entries, [](const Entry& lhs, const Entry& rhs) {
return lhs.position < rhs.position;
});
plans.reserve(plans.size() + num_defs);
for (const Entry& entry : entries) {
plans.push_back(ComposeDefPlan(entry.statements, entry.variant));
}
}
// Estimates the average number of lines in the plans of definitions with sizes
// following `sizes`. Uses `double` (like the other `EstimateAvg*Lines` helpers
// below) to accumulate fractional average line counts across variants and
// constructs before a single final rounding to a whole number of classes.
static auto EstimateAvgDefPlanLines(
llvm::ArrayRef<SourceGen::DefSizeWeight> sizes) -> double {
// Average over enough variants that their rounding evens out.
constexpr int NumVariants = 16;
double lines = 0.0;
int64_t total_weight = 0;
for (const SourceGen::DefSizeWeight& size : sizes) {
int size_lines = 0;
for (int variant : llvm::seq(NumVariants)) {
size_lines += ComposeDefPlan(size.statements, variant).lines;
}
lines += static_cast<double>(size_lines) / NumVariants * size.weight;
total_weight += size.weight;
}
CARBON_CHECK(total_weight > 0,
"Definition sizes need a positive total weight.");
return lines / total_weight;
}
// The shuffled state used to generate some number of classes.
//
// This state encodes everything used to generate class definitions. The state
// will be consumed until empty.
//
// Detailed comments for out-of-line methods are on their definitions.
class SourceGen::ClassGenState {
public:
ClassGenState(SourceGen& gen, int num_classes, const DenseDeclParams& params);
auto public_function_param_counts() -> llvm::SmallVectorImpl<int>& {
return public_function_param_counts_;
}
auto public_method_param_counts() -> llvm::SmallVectorImpl<int>& {
return public_method_param_counts_;
}
auto private_function_param_counts() -> llvm::SmallVectorImpl<int>& {
return private_function_param_counts_;
}
auto private_method_param_counts() -> llvm::SmallVectorImpl<int>& {
return private_method_param_counts_;
}
auto inline_function_param_counts() -> llvm::SmallVectorImpl<int>& {
return inline_function_param_counts_;
}
auto forwarder_param_counts() -> llvm::SmallVectorImpl<int>& {
return forwarder_param_counts_;
}
// The plans of the out-of-line definitions, followed by those of inline
// function definitions, starting at `inline_def_plans_start()`. A definition
// uses the plan at the index of its return type's use among the plans of its
// kind; see `BuildTypePool`.
auto def_plans() -> llvm::ArrayRef<DefPlan> { return def_plans_; }
auto inline_def_plans_start() -> int { return inline_def_plans_start_; }
auto getter_field_types() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return getter_field_types_;
}
// The type of a field that a predicate tests, and the predicate template for
// that type.
struct PredicateField {
llvm::StringRef type;
llvm::StringRef predicate;
};
auto predicate_fields() -> llvm::SmallVectorImpl<PredicateField>& {
return predicate_fields_;
}
auto class_names() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return class_names_;
}
auto decl_names() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return decl_names_;
}
auto field_names() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return field_names_;
}
auto param_names() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return param_names_;
}
auto inline_function_names() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return inline_function_names_;
}
auto inline_param_names() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return inline_param_names_;
}
auto local_names() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return local_names_;
}
auto accessed_field_names() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return accessed_field_names_;
}
auto forwarder_names() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return forwarder_names_;
}
auto forwarder_param_names() -> llvm::SmallVectorImpl<llvm::StringRef>& {
return forwarder_param_names_;
}
auto AddValidTypeName(llvm::StringRef type_name) -> void {
valid_type_names_.Insert(type_name);
}
// The names of all classes in the file. Parameter, member, and field names
// exclude these so that they can't shadow a class that a definition names.
auto class_name_set() -> const Set<llvm::StringRef>& {
return class_name_set_;
}
// Emits an expression producing a value of `type`: a call to the class's
// `Make` function, or the fixed type's value expression.
auto ProduceValue(llvm::StringRef type, llvm::raw_ostream& os) -> void {
if (class_name_set_.Contains(type)) {
os << type << (is_cpp_ ? "()" : ".Make()");
} else {
os << fixed_value_.Lookup(type).value();
}
}
// A use of a type drawn from a pool, and its index in the pool before the
// pool was shuffled. A consumed use also has the consumer template that reads
// it.
struct TypeUse {
llvm::StringRef name;
llvm::StringRef consumer;
int index = -1;
};
// Each category of type use draws from its own pool so that every slot in a
// pool emits its type name (and any associated initializer, return value, or
// parameter-read expression) the same number of times. This keeps the
// generated file's byte count independent of how shuffling assigns types to
// slots within a pool.
// Return and parameter types of declarations without out-of-line
// definitions (spelled once).
auto GetDeclType() -> TypeUse { return GetValidTypeUse(decl_type_pool_); }
// Parameter types of inline function definitions (spelled once in the
// signature, and read once in the definition using a consumer template).
auto GetInlineParamType() -> TypeUse {
return GetValidTypeUse(inline_param_pool_);
}
// Return types of inline function definitions (spelled once in the
// signature, and constructed in `return` statements).
auto GetInlineReturnType() -> TypeUse {
return GetValidTypeUse(inline_return_pool_);
}
// Return types of declarations with out-of-line definitions (spelled in both
// the declaration and the definition, and constructed in `return`
// statements).
auto GetOutOfLineReturnType() -> TypeUse {
return GetValidTypeUse(out_of_line_return_pool_);
}
// Parameter types of declarations with out-of-line definitions (spelled in
// both the declaration and the definition, and read once in the definition
// using a consumer template).
auto GetOutOfLineParamType() -> TypeUse {
return GetValidTypeUse(out_of_line_param_pool_);
}
// Field types (spelled once in the field declaration, and initialized with a
// value expression in `Make` when the file has definitions).
auto GetFieldType() -> TypeUse { return GetValidTypeUse(field_type_pool_); }
// Return and parameter types of forwarders (spelled in both the forwarder
// and the `<name>Impl` declaration it calls).
auto GetForwardType() -> TypeUse {
return GetValidTypeUse(forward_type_pool_);
}
auto has_defs() -> bool { return has_defs_; }
auto define_decls_out_of_line() -> bool { return define_decls_out_of_line_; }
auto type_pools_empty() -> bool {
return decl_type_pool_.uses.empty() && inline_param_pool_.uses.empty() &&
inline_return_pool_.uses.empty() && field_type_pool_.uses.empty() &&
forward_type_pool_.uses.empty() &&
out_of_line_return_pool_.uses.empty() &&
out_of_line_param_pool_.uses.empty();
}
private:
// A pool of type uses, removed as they are emitted. `GetValidTypeUse` resumes
// its search at `last_index`.
struct TypePool {
llvm::SmallVector<TypeUse> uses;
int last_index = 0;
};
auto GetValidTypeUse(TypePool& pool) -> TypeUse;
auto BuildClassAndTypeNames(SourceGen& gen, int num_classes,
const ClassParams& class_params,
const TypeUseParams& type_use_params) -> void;
auto BuildTypePool(SourceGen& gen, int num_types, int max_refs_per_class,
bool needs_value_expr, bool consumed, bool for_fields,
const TypeUseParams& type_use_params) -> TypePool;
llvm::SmallVector<int> public_function_param_counts_;
llvm::SmallVector<int> public_method_param_counts_;
llvm::SmallVector<int> private_function_param_counts_;
llvm::SmallVector<int> private_method_param_counts_;
llvm::SmallVector<int> inline_function_param_counts_;
llvm::SmallVector<int> forwarder_param_counts_;
llvm::SmallVector<DefPlan> def_plans_;
int inline_def_plans_start_;
// Getters return a copy of their field, and `Make` initializes it, so getter
// and predicate fields have fixed types with a value expression. These types
// cycle through the eligible types in proportion to their weights, so that
// their spellings don't depend on the seed.
llvm::SmallVector<llvm::StringRef> getter_field_types_;
llvm::SmallVector<PredicateField> predicate_fields_;
llvm::SmallVector<llvm::StringRef> class_names_;
// Out-of-line definitions spell declared function and method names a second
// time, and `Make` does the same for field names, so these have separate
// pools.
llvm::SmallVector<llvm::StringRef> decl_names_;
llvm::SmallVector<llvm::StringRef> field_names_;
llvm::SmallVector<llvm::StringRef> param_names_;
// Inline function names are shorter than `MinMemberNameLength`, so they can't
// collide with class, member, or field names.
llvm::SmallVector<llvm::StringRef> inline_function_names_;
llvm::SmallVector<llvm::StringRef> inline_param_names_;
llvm::SmallVector<llvm::StringRef> local_names_;
// A getter or predicate spells its field's name again, and a forwarder's
// call and the declaration it calls spell its name and parameter names
// again, so these have separate pools.
llvm::SmallVector<llvm::StringRef> accessed_field_names_;
llvm::SmallVector<llvm::StringRef> forwarder_names_;
llvm::SmallVector<llvm::StringRef> forwarder_param_names_;
bool is_cpp_;
// Whether the file has any function or method definitions. Then each class
// also gets a `Make` function (a default constructor in C++), a `Checksum`
// method, and a `tag` field.
bool has_defs_;
bool define_decls_out_of_line_;
TypePool decl_type_pool_;
TypePool inline_param_pool_;
TypePool inline_return_pool_;
TypePool field_type_pool_;
TypePool forward_type_pool_;
TypePool out_of_line_return_pool_;
TypePool out_of_line_param_pool_;
Set<llvm::StringRef> valid_type_names_;
Set<llvm::StringRef> class_name_set_;
// The value expression and consumer templates of each fixed type, keyed by
// its spelling. These refer into the `TypeUseParams`, which outlives
// generation.
Map<llvm::StringRef, llvm::StringRef> fixed_value_;
Map<llvm::StringRef, llvm::ArrayRef<llvm::StringRef>> fixed_consumers_;
llvm::ArrayRef<llvm::StringRef> class_consumers_;
};
// A helper to sum elements of a range.
template <typename T>
static auto Sum(const T& range) -> int {
return std::accumulate(range.begin(), range.end(), 0);
}
// Given a number of class definitions and the params with which to generate
// them, builds the state that will be used while generating that many classes.
//
// We build the state first and across all the class definitions that will be
// generated so that we can distribute random components across all the
// definitions.
SourceGen::ClassGenState::ClassGenState(SourceGen& gen, int num_classes,
const DenseDeclParams& params)
: is_cpp_(gen.IsCpp()),
has_defs_(NumInlineDefsPerClass(params.class_params) > 0 ||
params.define_decls_out_of_line),
define_decls_out_of_line_(params.define_decls_out_of_line) {
const ClassParams& class_params = params.class_params;
public_function_param_counts_ =
gen.GetShuffledInts(num_classes * class_params.public_function_decls, 0,
class_params.public_function_decl_params.max_params);
public_method_param_counts_ =
gen.GetShuffledInts(num_classes * class_params.public_method_decls, 0,
class_params.public_method_decl_params.max_params);
private_function_param_counts_ =
gen.GetShuffledInts(num_classes * class_params.private_function_decls, 0,
class_params.private_function_decl_params.max_params);
private_method_param_counts_ =
gen.GetShuffledInts(num_classes * class_params.private_method_decls, 0,
class_params.private_method_decl_params.max_params);
int num_inline_functions = num_classes * class_params.inline_function_defs;
decl_names_ =
gen.GetShuffledIdentifiers(num_classes * NumDeclsPerClass(class_params),
/*min_length=*/MinMemberNameLength);
field_names_ =
gen.GetShuffledIdentifiers(num_classes * class_params.private_field_decls,
/*min_length=*/MinMemberNameLength);
int num_out_of_line_defs = define_decls_out_of_line_
? num_classes * NumDeclsPerClass(class_params)
: 0;
// Each out-of-line definition has one parameter beyond its random count; see
// `BuildClassAndTypeNames`.
int num_params = Sum(public_function_param_counts_) +
Sum(public_method_param_counts_) +
Sum(private_function_param_counts_) +
Sum(private_method_param_counts_) + num_out_of_line_defs;
param_names_ = gen.GetShuffledIdentifiers(num_params);
inline_function_param_counts_ =
gen.GetShuffledInts(num_inline_functions, 0,
class_params.inline_function_decl_params.max_params);
// Each inline definition has one parameter beyond its random count; see
// `BuildClassAndTypeNames`.
int num_inline_params =
Sum(inline_function_param_counts_) + num_inline_functions;
BuildDefPlans(num_out_of_line_defs, params.out_of_line_def_sizes, def_plans_);
inline_def_plans_start_ = def_plans_.size();
BuildDefPlans(num_inline_functions, class_params.inline_function_def_sizes,
def_plans_);
int num_locals = 0;
for (const DefPlan& plan : def_plans_) {
num_locals += plan.locals;
}
int num_getters = num_classes * class_params.inline_getters;
int num_predicates = num_classes * class_params.inline_predicates;
int num_forwarders = num_classes * class_params.inline_forwarders;
inline_function_names_ = gen.GetShuffledIdentifiers(
num_inline_functions + num_getters + num_predicates, /*min_length=*/2,
/*max_length=*/MinMemberNameLength - 1);
inline_param_names_ = gen.GetShuffledIdentifiers(num_inline_params);
local_names_ = gen.GetShuffledIdentifiers(num_locals,
/*min_length=*/LocalNameLength,
/*max_length=*/LocalNameLength);
accessed_field_names_ =
gen.GetShuffledIdentifiers(num_getters + num_predicates,
/*min_length=*/MinMemberNameLength);
forwarder_param_counts_ = gen.GetShuffledInts(
num_forwarders, 0, class_params.inline_forwarder_params.max_params);
forwarder_names_ =
gen.GetShuffledIdentifiers(num_forwarders, /*min_length=*/2,
/*max_length=*/MinMemberNameLength - 1);
forwarder_param_names_ =
gen.GetShuffledIdentifiers(Sum(forwarder_param_counts_));
BuildClassAndTypeNames(gen, num_classes, class_params,
params.type_use_params);
}
auto SourceGen::ClassGenState::GetValidTypeUse(TypePool& pool) -> TypeUse {
// Check that we don't completely wrap the type names by tracking where we
// started.
int initial_last_index = pool.last_index;
// Now search the type uses, starting from the last used index, to find the
// first valid one.
for (;;) {
if (pool.last_index == 0) {
pool.last_index = pool.uses.size();
}
--pool.last_index;
TypeUse& use = pool.uses[pool.last_index];
if (valid_type_names_.Contains(use.name)) {
// Found a valid type use, swap it with the back and pop that off.
std::swap(pool.uses.back(), use);
return pool.uses.pop_back_val();
}
// `BuildTypePool` caps the references to each class so that a valid type
// use always remains.
CARBON_CHECK(pool.last_index != initial_last_index,
"Failed to find a valid type name with {0} candidates, an "
"initial index of {1}, and with {2} classes left to emit!",
pool.uses.size(), initial_last_index, class_names_.size());
}
}
// Builds a shuffled pool of `num_types` type uses, mixing references to the
// classes with the fixed types to roughly match the weights in
// `type_use_params`. `max_refs_per_class` caps the references to each class.
//
// With `needs_value_expr`, the pool only includes fixed types that have a value
// expression (for initializing a field in `Make` or returning a value from a
// function definition). With `consumed`, each use gets one of its type's
// consumer templates, assigned round-robin per type before the shuffle so that
// the mix of templates doesn't depend on the seed. With `for_fields`, the pool
// is used for field types, which each class draws before becoming a valid type
// itself, so the pool excludes the last class defined in the file. Each use
// also records its pre-shuffle `index` in the pool so callers can pair it with
// other unshuffled per-function state (such as `def_plans_`), keeping the
// pairing and the resulting generated code size independent of the shuffle
// seed.
//
// `valid_type_names_` must already contain the fixed type spellings.
auto SourceGen::ClassGenState::BuildTypePool(
SourceGen& gen, int num_types, int max_refs_per_class,
bool needs_value_expr, bool consumed, bool for_fields,
const TypeUseParams& type_use_params) -> TypePool {
TypePool pool;
if (num_types == 0) {
return pool;
}
pool.uses.reserve(num_types);
auto fixed_spelling = [&](const TypeUseParams::FixedTypeWeight& fw) {
return gen.IsCpp() ? fw.cpp_spelling : fw.carbon_spelling;
};
auto fixed_usable = [&](const TypeUseParams::FixedTypeWeight& fw) {
return !needs_value_expr ||
!(gen.IsCpp() ? fw.cpp_value : fw.carbon_value).empty();
};
Map<llvm::StringRef, int> consumer_counters;
auto append_use = [&](llvm::StringRef name) {
llvm::StringRef consumer;
if (consumed) {
llvm::ArrayRef<llvm::StringRef> consumers =
class_name_set_.Contains(name)
? class_consumers_
: fixed_consumers_.Lookup(name).value();
int& counter = consumer_counters.Insert(name, 0).value();
consumer = consumers[counter++ % consumers.size()];
}
pool.uses.push_back({.name = name, .consumer = consumer});
};
int type_weight_sum = type_use_params.declared_types_weight;
for (const auto& fixed_type_weight : type_use_params.fixed_type_weights) {
if (fixed_usable(fixed_type_weight)) {
type_weight_sum += fixed_type_weight.weight;
}
}
// Compute the number of declared types used. We expect to have a decent
// number of repeated names, so we repeatedly append the entire sequence of
// class names until there is some remainder of names needed. The class
// defined last has the first unshuffled name; see `BuildClassAndTypeNames`.
llvm::ArrayRef<llvm::StringRef> classes = class_names_;
if (for_fields) {
classes = classes.drop_front();
}
int num_classes = classes.size();
int num_declared_types =
num_classes == 0
? 0
: num_types * type_use_params.declared_types_weight / type_weight_sum;
int full_copies = num_classes == 0 ? 0 : num_declared_types / num_classes;
int remainder = num_classes == 0 ? 0 : num_declared_types % num_classes;
// Cap the references to each class so that `GetValidTypeUse` always finds a
// valid type regardless of the shuffle order:
// - For function and method signature pools (`!for_fields`), a class is added
// to `valid_type_names_` after its fields are chosen, so references to a
// class can only be used on its own functions/methods or in later classes.
// In particular, the last class defined in the file can only be referenced
// by its own functions/methods, so each class can be referenced at most
// `max_refs_per_class` times (the number of draws per class from this
// pool).
// - For `field_type_pool_` (`for_fields`), a class cannot have a field of its
// own type or any later class's type. Excluding the last class defined in
// the file ensures every remaining class is valid during at least the last
// class's field draws, and in general the `k` classes defined after the
// current class draw `k * private_field_decls` fields total, so capping
// each class at `private_field_decls` references guarantees a valid field
// type is always available.
//
// The fixed types below replace any references removed by the cap, so the
// pool's spellings and total byte count remain independent of the shuffle.
if (full_copies >= max_refs_per_class) {
full_copies = max_refs_per_class;
remainder = 0;
}
for (auto _ : llvm::seq(full_copies)) {
for (llvm::StringRef name : classes) {
append_use(name);
}
}
// Now append the remainder number of class names. This is where the class
// names being un-shuffled is essential. We're going to have one extra
// reference to some fraction of the class names and we want that to be a
// stable subset.
for (llvm::StringRef name : classes.slice(0, remainder)) {
append_use(name);
}
num_declared_types = full_copies * num_classes + remainder;
CARBON_CHECK(static_cast<int>(pool.uses.size()) == num_declared_types);
// Use each fixed type weight to append the expected number of copies of that
// type. This isn't exact however, and is designed to stop short.
for (const auto& fixed_type_weight : type_use_params.fixed_type_weights) {
if (!fixed_usable(fixed_type_weight)) {
continue;
}
int num_fixed_type = num_types * fixed_type_weight.weight / type_weight_sum;
for (auto _ : llvm::seq(num_fixed_type)) {
append_use(fixed_spelling(fixed_type_weight));
}
}
// If we need a tail of types to hit the exact number, simply round-robin
// through the usable fixed types without any weighting. With reasonably large
// numbers of types this won't distort the distribution in an interesting way
// and is simpler than trying to scale the distribution down.
while (static_cast<int>(pool.uses.size()) < num_types) {
for (const auto& fixed_type_weight : type_use_params.fixed_type_weights) {
if (static_cast<int>(pool.uses.size()) >= num_types) {
break;
}
if (fixed_usable(fixed_type_weight)) {
append_use(fixed_spelling(fixed_type_weight));
}
}
}
CARBON_CHECK(static_cast<int>(pool.uses.size()) == num_types);
pool.last_index = num_types;
for (auto [index, use] : llvm::enumerate(pool.uses)) {
use.index = static_cast<int>(index);
}
std::shuffle(pool.uses.begin(), pool.uses.end(), gen.rng_);
return pool;
}
// Builds the class names and the type use pools. Each pool caps the references
// to each class at the number of uses each class draws from it after its
// fields; see `BuildTypePool`.
auto SourceGen::ClassGenState::BuildClassAndTypeNames(
SourceGen& gen, int num_classes, const ClassParams& class_params,
const TypeUseParams& type_use_params) -> void {
// Initially get the sequence of class names without shuffling so we can
// compute our type pools from them prior to any shuffling.
class_names_ =
gen.GetUniqueIdentifiers(num_classes, /*min_length=*/MinClassNameLength);
for (llvm::StringRef name : class_names_) {
class_name_set_.Insert(name);
}
// Every fixed type needs a consumer template, since any of them can be the
// type of a consumed parameter.
for (const auto& fw : type_use_params.fixed_type_weights) {
llvm::StringRef spelling =
gen.IsCpp() ? fw.cpp_spelling : fw.carbon_spelling;
valid_type_names_.Insert(spelling);
fixed_value_.Insert(spelling, gen.IsCpp() ? fw.cpp_value : fw.carbon_value);
llvm::ArrayRef<llvm::StringRef> consumers =
gen.IsCpp() ? fw.cpp_consumers : fw.carbon_consumers;
CARBON_CHECK(!consumers.empty(),
"Fixed type `{0}` needs at least one consumer template.",
spelling);
for (llvm::StringRef consumer : consumers) {
CARBON_CHECK(consumer.contains("{0}"),
"Fixed type `{0}` has a consumer template without a name "
"placeholder.",
spelling);
}
fixed_consumers_.Insert(spelling, consumers);
}
CARBON_CHECK(!type_use_params.class_consumers.empty(),
"Class types need at least one consumer template.");
class_consumers_ = type_use_params.class_consumers;
int decls_per_class = NumDeclsPerClass(class_params);
int num_decl_returns = num_classes * decls_per_class;
int num_decl_params =
Sum(public_function_param_counts_) + Sum(public_method_param_counts_) +
Sum(private_function_param_counts_) + Sum(private_method_param_counts_);
int num_inline_returns = num_classes * class_params.inline_function_defs;
int num_inline_params = Sum(inline_function_param_counts_);
int num_fields = num_classes * class_params.private_field_decls;
// Each class draws `inline_function_defs` return types from this pool after
// its fields. As for out-of-line definitions, a definition's guards also
// return values of its return type, so each use's pre-shuffle index pairs it
// with a definition plan.
inline_return_pool_ =
BuildTypePool(gen, num_inline_returns, class_params.inline_function_defs,
/*needs_value_expr=*/true, /*consumed=*/false,
/*for_fields=*/false, type_use_params);
// Each class draws `private_field_decls` field types from this pool before
// becoming a valid type itself. When the file has definitions, `Make`
// initializes every field with a value expression.
field_type_pool_ =
BuildTypePool(gen, num_fields, class_params.private_field_decls,
/*needs_value_expr=*/has_defs_, /*consumed=*/false,
/*for_fields=*/true, type_use_params);
// Each inline definition has one parameter beyond its random count, so that
// each class draws at least `inline_function_defs` parameter types from this
// pool, and the pool can include class types.
int num_inline_extra_params = num_inline_returns;
inline_param_pool_ =
BuildTypePool(gen, num_inline_params + num_inline_extra_params,
class_params.inline_function_defs,
/*needs_value_expr=*/false, /*consumed=*/true,
/*for_fields=*/false, type_use_params);
if (!define_decls_out_of_line_) {
// Each class draws `decls_per_class` return types from this pool after its
// fields.
decl_type_pool_ =
BuildTypePool(gen, num_decl_returns + num_decl_params, decls_per_class,
/*needs_value_expr=*/false, /*consumed=*/false,
/*for_fields=*/false, type_use_params);
} else {
// Each class draws `decls_per_class` return types from this pool after its
// fields. A definition's guards also return values of its return type, so
// each use's pre-shuffle index pairs it with the definition plan at the
// same index.
out_of_line_return_pool_ =
BuildTypePool(gen, num_decl_returns, decls_per_class,
/*needs_value_expr=*/true, /*consumed=*/false,
/*for_fields=*/false, type_use_params);
// As for inline definitions, each declaration has one parameter beyond its
// random count, so that each class draws at least `decls_per_class`
// parameter types from this pool.
int num_decl_extra_params = num_decl_returns;
out_of_line_param_pool_ = BuildTypePool(
gen, num_decl_params + num_decl_extra_params, decls_per_class,
/*needs_value_expr=*/false, /*consumed=*/true, /*for_fields=*/false,
type_use_params);
}
// Each class draws `inline_forwarders` return types from this pool after its
// fields.
forward_type_pool_ =
BuildTypePool(gen,
num_classes * class_params.inline_forwarders +
Sum(forwarder_param_counts_),
class_params.inline_forwarders,
/*needs_value_expr=*/false, /*consumed=*/false,
/*for_fields=*/false, type_use_params);
auto value = [&](const TypeUseParams::FixedTypeWeight& fw) {
return gen.IsCpp() ? fw.cpp_value : fw.carbon_value;
};
auto predicate = [&](const TypeUseParams::FixedTypeWeight& fw) {
return gen.IsCpp() ? fw.cpp_predicate : fw.carbon_predicate;
};
auto spelling = [&](const TypeUseParams::FixedTypeWeight& fw) {
return gen.IsCpp() ? fw.cpp_spelling : fw.carbon_spelling;
};
int num_getters = num_classes * class_params.inline_getters;
auto getter_types = WeightedFixedTypes(
type_use_params, [&](const auto& fw) { return !value(fw).empty(); });
CARBON_CHECK(num_getters == 0 || !getter_types.empty(),
"Getters need a fixed type with a value expression.");
for (int i : llvm::seq(num_getters)) {
getter_field_types_.push_back(
spelling(*getter_types[i % getter_types.size()]));
}
std::shuffle(getter_field_types_.begin(), getter_field_types_.end(),
gen.rng_);
int num_predicates = num_classes * class_params.inline_predicates;
auto predicate_types =
WeightedFixedTypes(type_use_params, [&](const auto& fw) {
return !value(fw).empty() && !predicate(fw).empty();
});
CARBON_CHECK(num_predicates == 0 || !predicate_types.empty(),
"Predicates need a fixed type with a value expression and a "
"predicate template.");
for (int i : llvm::seq(num_predicates)) {
const auto& fw = *predicate_types[i % predicate_types.size()];
predicate_fields_.push_back(
{.type = spelling(fw), .predicate = predicate(fw)});
}
std::shuffle(predicate_fields_.begin(), predicate_fields_.end(), gen.rng_);
// Classes are defined from the back, so the first unshuffled name is always
// the class defined last, which field pools leave out; see `BuildTypePool`.
std::shuffle(class_names_.begin() + 1, class_names_.end(), gen.rng_);
}
// Some heuristic numbers used when formatting generated code. These heuristics
// are loosely based on what we expect to make Carbon code readable, and might
// not fit as well in C++, but we use the same heuristics across languages for
// simplicity and to make the output in different languages more directly
// comparable.
static constexpr int NumSingleLineFunctionParams = 3;
static constexpr int NumSingleLineMethodParams = 2;
static constexpr int MaxParamsPerLine = 4;
// `extra_params` is the number of parameters a function has beyond its random
// count.
static auto EstimateAvgFunctionDeclLines(SourceGen::FunctionDeclParams params,
int extra_params = 0) -> double {
// Currently model a uniform distribution [0, max] random parameters. Assume
// a line break before the first parameter for >3 and after every 4th.
int param_lines = 0;
for (int num_params :
llvm::seq_inclusive(extra_params, params.max_params + extra_params)) {
if (num_params > NumSingleLineFunctionParams) {
param_lines += (num_params + MaxParamsPerLine - 1) / MaxParamsPerLine;
}
}
return 1.0 + static_cast<double>(param_lines) / (params.max_params + 1);
}
// See `EstimateAvgFunctionDeclLines` for the meaning of `extra_params`.
static auto EstimateAvgMethodDeclLines(SourceGen::MethodDeclParams params,
int extra_params = 0) -> double {
// Currently model a uniform distribution [0, max] random parameters. Assume
// a line break before the first parameter for >2 and after every 4th slot,
// where a Carbon method's `self` takes the first slot. C++ methods have no
// `self`, so this slightly overestimates their lines.
int param_lines = 0;
for (int num_params :
llvm::seq_inclusive(extra_params, params.max_params + extra_params)) {
if (num_params > NumSingleLineMethodParams) {
param_lines += 1 + num_params / MaxParamsPerLine;
}
}
return 1.0 + static_cast<double>(param_lines) / (params.max_params + 1);
}
// Estimates the average number of lines in an inline function definition,
// excluding its comment. The definition has an accumulator line, a line reading
// the parameters, its plan's lines, a return line, and a closing brace line.
static auto EstimateAvgInlineFunctionDefLines(
const SourceGen::ClassParams& params) -> double {
constexpr int ExtraParams = 1;
return EstimateAvgFunctionDeclLines(params.inline_function_decl_params,
ExtraParams) +
4.0 + EstimateAvgDefPlanLines(params.inline_function_def_sizes);
}
// Note that this should match the heuristics used when formatting.
// TODO: See top-level TODO about line estimates and formatting.
static auto EstimateAvgClassDefLines(
const SourceGen::DenseDeclParams& dense_params) -> double {
const SourceGen::ClassParams& params = dense_params.class_params;
bool define_decls_out_of_line = dense_params.define_decls_out_of_line;
// Comment line, and class open line.
double avg = 2.0;
// Declarations with out-of-line definitions have an extra parameter.
int decl_extra_params = define_decls_out_of_line ? 1 : 0;
// One comment line and blank line per function, plus the function lines.
avg += (2.0 + EstimateAvgFunctionDeclLines(params.public_function_decl_params,
decl_extra_params)) *
params.public_function_decls;
avg += (2.0 + EstimateAvgMethodDeclLines(params.public_method_decl_params,
decl_extra_params)) *
params.public_method_decls;
avg += (2.0 + EstimateAvgFunctionDeclLines(
params.private_function_decl_params, decl_extra_params)) *
params.private_function_decls;
avg += (2.0 + EstimateAvgMethodDeclLines(params.private_method_decl_params,
decl_extra_params)) *
params.private_method_decls;
avg += (2.0 + EstimateAvgInlineFunctionDefLines(params)) *
params.inline_function_defs;
// Getters and predicates are on one line.
avg += 3.0 * (params.inline_getters + params.inline_predicates);
// A forwarder's definition has a return line and a closing brace line, and
// the declaration it calls has the same signature.
double forwarder_signature_lines =
EstimateAvgMethodDeclLines(params.inline_forwarder_params);
avg += (2.0 + forwarder_signature_lines + 2.0 + 2.0 +
forwarder_signature_lines) *
params.inline_forwarders;
bool has_defs = NumInlineDefsPerClass(params) > 0 || define_decls_out_of_line;
// A blank line and all the fields (if any), including `tag` when the file has
// definitions.
double num_fields = params.private_field_decls + params.inline_getters +
params.inline_predicates + (has_defs ? 1.0 : 0.0);
if (num_fields > 0) {
avg += 1.0 + num_fields;
}
// `Make` and `Checksum` each have a blank line, a comment line, a signature
// line, a return line, and a closing brace line. A C++ constructor puts its
// initializers and empty definition on one line, so this overestimates C++ by
// a line.
if (has_defs) {
avg += 10.0;
}
// Each out-of-line definition has a blank line, a comment line, a signature
// line, an accumulator line, a line reading the parameters, its plan's lines,
// a return line, and a closing brace line.
if (define_decls_out_of_line) {
avg += (7.0 + EstimateAvgDefPlanLines(dense_params.out_of_line_def_sizes)) *
NumDeclsPerClass(params);
}
// No need to account for the class close line, we have an extra blank line
// count for the last of the above.
return avg;
}
auto SourceGen::GenApiFileDenseDecls(int target_lines,
const DenseDeclParams& params)
-> std::string {
RawStringOstream source;
// Figure out how many classes fit in our target lines, each separated by a
// blank line. We need to account the comment lines below to start the file.
// Note that we want a blank line after our file comment block, so every class
// needs a blank line.
constexpr int NumFileCommentLines = 4;
double avg_class_lines = EstimateAvgClassDefLines(params);
CARBON_CHECK(target_lines > NumFileCommentLines + avg_class_lines,
"Not enough target lines to generate a single class!");
// Round to the nearest whole class. Truncating can leave the file nearly a
// whole class short of the target, which matters when classes with
// definitions run to hundreds of lines.
int num_classes =
std::lround((target_lines - NumFileCommentLines) / (avg_class_lines + 1));
int expected_lines =
NumFileCommentLines + num_classes * (avg_class_lines + 1);
source << "// Generated " << (!IsCpp() ? "Carbon" : "C++")
<< " source file.\n";
source << llvm::formatv(
"// {0} target lines: {1} classes, {2} expected lines",
target_lines, num_classes, expected_lines)
<< "\n";
source << "//\n// Generating as "
<< (params.define_decls_out_of_line
? "an implementation file with out-of-line definitions"
: "an API file with dense declarations")
<< ".\n";
// Carbon uses an implicitly imported prelude to get builtin types, but C++
// requires header files so include those.
if (IsCpp()) {
source << "\n";
// Header for specific integer types like `std::int64_t`.
source << "#include <cstdint>\n";
// Header for `std::pair`.
source << "#include <utility>\n";
}
auto class_gen_state = ClassGenState(*this, num_classes, params);
llvm::SmallVector<OutOfLineDef, 0> out_of_line_defs;
for (auto _ : llvm::seq(num_classes)) {
source << "\n";
GenerateClassDef(params.class_params, class_gen_state, source,
out_of_line_defs);
}
// Out-of-line definitions follow every class, as in an implementation file,
// where all of the API's declarations are visible.
for (const OutOfLineDef& def : out_of_line_defs) {
source << "\n";
GenerateOutOfLineDef(class_gen_state, def.class_name, def.sig, source);
}
// Make sure we consumed all the state.
CARBON_CHECK(class_gen_state.public_function_param_counts().empty());
CARBON_CHECK(class_gen_state.public_method_param_counts().empty());
CARBON_CHECK(class_gen_state.private_function_param_counts().empty());
CARBON_CHECK(class_gen_state.private_method_param_counts().empty());
CARBON_CHECK(class_gen_state.inline_function_param_counts().empty());
CARBON_CHECK(class_gen_state.forwarder_param_counts().empty());
CARBON_CHECK(class_gen_state.getter_field_types().empty());
CARBON_CHECK(class_gen_state.predicate_fields().empty());
CARBON_CHECK(class_gen_state.class_names().empty());
CARBON_CHECK(class_gen_state.type_pools_empty());
// The identifier lengths in each name pool don't depend on the seed, so
// emitting every name keeps the byte count seed-independent.
CARBON_CHECK(class_gen_state.decl_names().empty());
CARBON_CHECK(class_gen_state.field_names().empty());
CARBON_CHECK(class_gen_state.param_names().empty());
CARBON_CHECK(class_gen_state.inline_function_names().empty());
CARBON_CHECK(class_gen_state.inline_param_names().empty());
CARBON_CHECK(class_gen_state.local_names().empty());
CARBON_CHECK(class_gen_state.accessed_field_names().empty());
CARBON_CHECK(class_gen_state.forwarder_names().empty());
CARBON_CHECK(class_gen_state.forwarder_param_names().empty());
return source.TakeStr();
}
auto SourceGen::GetShuffledIdentifiers(int number, int min_length,
int max_length, bool uniform)
-> llvm::SmallVector<llvm::StringRef> {
llvm::SmallVector<llvm::StringRef> idents =
GetIdentifiers(number, min_length, max_length, uniform);
std::shuffle(idents.begin(), idents.end(), rng_);
return idents;
}
auto SourceGen::GetShuffledUniqueIdentifiers(int number, int min_length,
int max_length, bool uniform)
-> llvm::SmallVector<llvm::StringRef> {
CARBON_CHECK(min_length >= 4,
"Cannot trivially guarantee enough distinct, unique identifiers "
"for lengths <= 3");
llvm::SmallVector<llvm::StringRef> idents =
GetUniqueIdentifiers(number, min_length, max_length, uniform);
std::shuffle(idents.begin(), idents.end(), rng_);
return idents;
}
auto SourceGen::GetIdentifiers(int number, int min_length, int max_length,
bool uniform)
-> llvm::SmallVector<llvm::StringRef> {
llvm::SmallVector<llvm::StringRef> idents = GetIdentifiersImpl(
number, min_length, max_length, uniform,
[this](int length, int length_count,
llvm::SmallVectorImpl<llvm::StringRef>& dest) {
llvm::append_range(dest,
GetSingleLengthIdentifiers(length, length_count));
});
return idents;
}
auto SourceGen::GetUniqueIdentifiers(int number, int min_length, int max_length,
bool uniform)
-> llvm::SmallVector<llvm::StringRef> {
CARBON_CHECK(min_length >= 4,
"Cannot trivially guarantee enough distinct, unique identifiers "
"for lengths <= 3");
llvm::SmallVector<llvm::StringRef> idents =
GetIdentifiersImpl(number, min_length, max_length, uniform,
[this](int length, int length_count,
llvm::SmallVectorImpl<llvm::StringRef>& dest) {
AppendUniqueIdentifiers(length, length_count, dest);
});
return idents;
}
auto SourceGen::GetSingleLengthIdentifiers(int length, int number)
-> llvm::ArrayRef<llvm::StringRef> {
llvm::SmallVector<llvm::StringRef>& idents =
identifiers_by_length_.Insert(length, {}).value();
if (static_cast<int>(idents.size()) < number) {
idents.reserve(number);
for (auto _ : llvm::seq<int>(idents.size(), number)) {
auto ident_storage =
llvm::MutableArrayRef(reinterpret_cast<char*>(storage_.Allocate(
/*Size=*/length, /*Alignment=*/1)),
length);
GenerateRandomIdentifier(ident_storage);
llvm::StringRef new_id(ident_storage.data(), length);
idents.push_back(new_id);
}
CARBON_CHECK(static_cast<int>(idents.size()) == number);
}
return llvm::ArrayRef(idents).slice(0, number);
}
static auto IdentifierStartChars() -> llvm::ArrayRef<char> {
static llvm::SmallVector<char> chars = [] {
llvm::SmallVector<char> chars;
for (char c : llvm::seq_inclusive('A', 'Z')) {
chars.push_back(c);
}
for (char c : llvm::seq_inclusive('a', 'z')) {
chars.push_back(c);
}
return chars;
}();
return chars;
}
static auto IdentifierChars() -> llvm::ArrayRef<char> {
static llvm::SmallVector<char> chars = [] {
llvm::ArrayRef<char> start_chars = IdentifierStartChars();
llvm::SmallVector<char> chars(start_chars.begin(), start_chars.end());
chars.push_back('_');
for (char c : llvm::seq_inclusive('0', '9')) {
chars.push_back(c);
}
return chars;
}();
return chars;
}
static constexpr llvm::StringRef NonCarbonCppKeywords[] = {
"asm", "catch", "do", "double", "float", "goto", "int",
"long", "new", "operator", "signed", "std", "this", "throw",
"try", "typename", "unix", "unsigned", "using", "xor", "M_E",
"M_El", "M_PI", "NAN", "NULL",
};
// Names that generated code declares itself, which random identifiers must
// avoid. For example, an inline function named `Make` would collide with its
// class's `Make` function.
static constexpr llvm::StringRef ReservedGeneratedNames[] = {"Make", "Checksum",
"acc", "tag"};
// Returns a random identifier string of the specified length.
//
// Ensures this is a valid identifier, avoiding any overlapping syntaxes or
// keywords both in Carbon and C++.
//
// This routine is somewhat expensive and so is useful to cache and reduce the
// frequency of calls. However, each time it is called it computes a completely
// new random identifier and so can be useful to eventually find a distinct
// identifier when needed.
auto SourceGen::GenerateRandomIdentifier(
llvm::MutableArrayRef<char> dest_storage) -> void {
llvm::ArrayRef<char> start_chars = IdentifierStartChars();
llvm::ArrayRef<char> chars = IdentifierChars();
llvm::StringRef ident(dest_storage.data(), dest_storage.size());
do {
dest_storage[0] =
start_chars[absl::Uniform<int>(rng_, 0, start_chars.size())];
for (int i : llvm::seq<int>(1, dest_storage.size())) {
dest_storage[i] = chars[absl::Uniform<int>(rng_, 0, chars.size())];
}
} while (
// TODO: Clean up and simplify this code. With some small refactorings and
// post-processing we should be able to make this both easier to read and
// less inefficient.
llvm::any_of(
Lex::TokenKind::KeywordTokens,
[ident](auto token) { return ident == token.fixed_spelling(); }) ||
llvm::is_contained(NonCarbonCppKeywords, ident) ||
llvm::is_contained(ReservedGeneratedNames, ident) ||
ident.ends_with("Impl") || ident.ends_with("_t") ||
ident.ends_with("_MIN") || ident.ends_with("_MAX") ||
ident.ends_with("_C") ||
(llvm::is_contained({'i', 'u', 'f'}, ident[0]) &&
llvm::all_of(ident.substr(1),
[](const char c) { return llvm::isDigit(c); })));
}
// Appends a number of unique, random identifiers with a particular length to
// the provided destination vector.
//
// Uses, and when necessary grows, a cached sequence of random identifiers with
// the specified length. Because these are cached, this is efficient to call
// repeatedly, but will not produce a different sequence of identifiers.
auto SourceGen::AppendUniqueIdentifiers(
int length, int number, llvm::SmallVectorImpl<llvm::StringRef>& dest)
-> void {
auto& [count, unique_idents] =
unique_identifiers_by_length_.Insert(length, {}).value();
// See if we need to grow our pool of unique identifiers with the requested
// length.
if (count < number) {
// We'll need to insert exactly the requested new unique identifiers. All
// our other inserts will find an existing entry.
unique_idents.GrowForInsertCount(count - number);
// Generate the needed number of identifiers.
for (auto _ : llvm::seq<int>(count, number)) {
// Allocate stable storage for the identifier so we can form stable
// `StringRef`s to it.
auto ident_storage =
llvm::MutableArrayRef(reinterpret_cast<char*>(storage_.Allocate(
/*Size=*/length, /*Alignment=*/1)),
length);
// Repeatedly generate novel identifiers of this length until we find a
// new unique one.
for (;;) {
GenerateRandomIdentifier(ident_storage);
auto result =
unique_idents.Insert(llvm::StringRef(ident_storage.data(), length));
if (result.is_inserted()) {
break;
}
}
}
count = number;
}
// Append all the identifiers directly out of the set. We make no guarantees
// about the relative order so we just use the non-deterministic order of the
// set and avoid additional storage.
for (llvm::StringRef ident : unique_idents.entries()) {
if (number == 0) {
break;
}
dest.push_back(ident);
--number;
}
CARBON_CHECK(number == 0);
}
// An array of the counts that should be used for each identifier length to
// produce our desired distribution.
//
// Note that the zero-based index corresponds to a 1-based length, so the count
// for identifiers of length 1 is at index 0.
static constexpr std::array<int, 64> IdentifierLengthCounts = [] {
std::array<int, 64> ident_length_counts;
// For non-uniform distribution, we simulate a distribution roughly based on
// the observed histogram of identifier lengths, but smoothed a bit and
// reduced to small counts so that we cycle through all the lengths
// reasonably quickly. We want sampling of even 10% of NumTokens from this
// in a round-robin form to not be skewed overly much. This still inherently
// compresses the long tail as we'd rather have coverage even though it
// distorts the distribution a bit.
//
// The distribution here comes from a script that analyzes source code run
// over a few directories of LLVM. The script renders a visual ascii-art
// histogram along with the data for each bucket, and that output is
// included in comments above each bucket size below to help visualize the
// rough shape we're aiming for.
//
// 1 characters [3976] ███████████████████████████████▊
ident_length_counts[0] = 40;
// 2 characters [3724] █████████████████████████████▊
ident_length_counts[1] = 40;
// 3 characters [4173] █████████████████████████████████▍
ident_length_counts[2] = 40;
// 4 characters [5000] ████████████████████████████████████████
ident_length_counts[3] = 50;
// 5 characters [1568] ████████████▌
ident_length_counts[4] = 20;
// 6 characters [2226] █████████████████▊
ident_length_counts[5] = 20;
// 7 characters [2380] ███████████████████
ident_length_counts[6] = 20;
// 8 characters [1786] ██████████████▎
ident_length_counts[7] = 18;
// 9 characters [1397] ███████████▏
ident_length_counts[8] = 12;
// 10 characters [ 739] █████▉
ident_length_counts[9] = 12;
// 11 characters [ 779] ██████▎
ident_length_counts[10] = 12;
// 12 characters [1344] ██████████▊
ident_length_counts[11] = 12;
// 13 characters [ 498] ████
ident_length_counts[12] = 5;
// 14 characters [ 284] ██▎
ident_length_counts[13] = 3;
// 15 characters [ 172] █▍
// 16 characters [ 278] ██▎
// 17 characters [ 191] █▌
// 18 characters [ 207] █▋
for (int i = 14; i < 18; ++i) {
ident_length_counts[i] = 2;
}
// 19 - 63 characters are all <100 but non-zero, and we map them to 1 for
// coverage despite slightly over weighting the tail.
for (int i = 18; i < 64; ++i) {
ident_length_counts[i] = 1;
}
return ident_length_counts;
}();
// A template function that implements the common logic of `GetIdentifiers` and
// `GetUniqueIdentifiers`. Most parameters correspond to the parameters of those
// functions. Additionally, an `AppendFunc` callable is provided to implement
// the appending operation.
//
// The main functionality provided here is collecting the correct number of
// identifiers from each of the lengths in the range [min_length, max_length]
// and either in our default representative distribution or a uniform
// distribution.
auto SourceGen::GetIdentifiersImpl(int number, int min_length, int max_length,
bool uniform,
llvm::function_ref<AppendFn> append)
-> llvm::SmallVector<llvm::StringRef> {
CARBON_CHECK(min_length <= max_length);
CARBON_CHECK(
uniform || max_length <= 64,
"Cannot produce a meaningful non-uniform distribution of lengths longer "
"than 64 as those are exceedingly rare in our observed data sets.");
llvm::SmallVector<llvm::StringRef> idents;
idents.reserve(number);
// First, compute the total weight of the distribution so we know how many
// identifiers we'll get each time we collect from it. For a uniform
// distribution every length has weight one, so the sum is simply the number
// of lengths; this also avoids indexing the bounded `IdentifierLengthCounts`
// table, which only covers lengths up to 64 and which uniform callers are
// allowed to exceed.
int num_lengths = max_length - min_length + 1;
int count_sum = uniform ? num_lengths
: Sum(llvm::ArrayRef(IdentifierLengthCounts)
.slice(min_length - 1, num_lengths));
CARBON_CHECK(count_sum >= 1);
int number_rem = number % count_sum;
// Finally, walk through each length in the distribution.
for (int length : llvm::seq_inclusive(min_length, max_length)) {
// Scale how many identifiers we want of this length if computing a
// non-uniform distribution. For uniform, we always take one.
int scale = uniform ? 1 : IdentifierLengthCounts[length - 1];
// Now we can compute how many identifiers of this length to request.
int length_count = (number / count_sum) * scale;
if (number_rem > 0) {
int rem_adjustment = std::min(scale, number_rem);
length_count += rem_adjustment;
number_rem -= rem_adjustment;
}
append(length, length_count, idents);
}
CARBON_CHECK(number_rem == 0, "Unexpected number remaining: {0}", number_rem);
CARBON_CHECK(static_cast<int>(idents.size()) == number,
"Ended up with {0} identifiers instead of the requested {1}",
idents.size(), number);
return idents;
}
// Returns a shuffled sequence of integers in the range [min, max].
//
// The order of the returned integers is random, but each integer in the range
// appears the same number of times in the result, with the number of
// appearances rounded up for lower numbers and rounded down for higher numbers
// in order to exactly produce `number` results.
auto SourceGen::GetShuffledInts(int number, int min, int max)
-> llvm::SmallVector<int> {
llvm::SmallVector<int> ints;
ints.reserve(number);
// Evenly distribute to each value between min and max.
int num_values = max - min + 1;
for (int i : llvm::seq_inclusive(min, max)) {
int i_count = number / num_values;
i_count += i < (min + (number % num_values));
ints.append(i_count, i);
}
CARBON_CHECK(static_cast<int>(ints.size()) == number);
std::shuffle(ints.begin(), ints.end(), rng_);
return ints;
}
// A helper to pop series of unique identifiers off a sequence of random
// identifiers that may have duplicates.
//
// This is particularly designed to work with the sequences of non-unique
// identifiers produced by `GetShuffledIdentifiers` with the important property
// that while popping off unique identifiers found in the shuffled list, we
// don't change the distribution of identifier lengths.
//
// The uniqueness is only per-instance of the class, and so an instance can be
// used to extract a series of names that share a scope.
//
// It works by scanning the sequence to extract each unique identifier found,
// swapping it to the back and popping it off the list. This does shuffle the
// order, but it isn't expected to do so in an interesting way.
//
// It also provides a fallback path in case there are no unique identifiers left
// which computes fresh, random identifiers with the same length as the next one
// in the sequence until a unique one is found.
//
// For simplicity of the fallback path, the lifetime of the identifiers produced
// is bound to the lifetime of the popper instance, and not the generator as a
// whole. If this is ever a problematic constraint, we can start copying
// fallback identifiers into the generator's storage.
class SourceGen::UniqueIdentifierPopper {
public:
// The popper never returns an identifier in `excluded`. `excluded` isn't
// copied, so it must outlive the popper and not change while it's in use.
explicit UniqueIdentifierPopper(
SourceGen& gen, llvm::SmallVectorImpl<llvm::StringRef>& data,
const Set<llvm::StringRef>* excluded = nullptr)
: gen_(&gen), data_(&data), it_(data_->rbegin()), excluded_(excluded) {}
// The identifiers this popper has returned.
auto used() const -> const Set<llvm::StringRef>& { return set_; }
// Prevents this popper from returning any of `names`, which are copied.
auto Reserve(const Set<llvm::StringRef>& names) -> void {
for (llvm::StringRef name : names.entries()) {
set_.Insert(name);
}
}
// Pop the next unique identifier that can be found in the data, or synthesize
// one with a valid length. Always consumes exactly one identifier from the
// data.
//
// Note that the lifetime of the underlying identifier is that of the popper
// and not the underlying data.
auto Pop() -> llvm::StringRef {
for (auto end = data_->rend(); it_ != end; ++it_) {
if (excluded_ && excluded_->Contains(*it_)) {
continue;
}
auto insert = set_.Insert(*it_);
if (!insert.is_inserted()) {
continue;
}
if (it_ != data_->rbegin()) {
std::swap(*data_->rbegin(), *it_);
}
CARBON_CHECK(insert.key() == data_->back());
return data_->pop_back_val();
}
// Out of unique elements. Overwrite the back, preserving its length,
// generating a new identifiers until we find a unique one and return that.
// This ensures we continue to consume the structure and produce the same
// size identifiers even in the fallback.
int length = data_->pop_back_val().size();
auto fallback_ident_storage =
llvm::MutableArrayRef(reinterpret_cast<char*>(gen_->storage_.Allocate(
/*Size=*/length, /*Alignment=*/1)),
length);
for (;;) {
gen_->GenerateRandomIdentifier(fallback_ident_storage);
auto fallback_id = llvm::StringRef(fallback_ident_storage.data(), length);
if (excluded_ && excluded_->Contains(fallback_id)) {
continue;
}
if (set_.Insert(fallback_id).is_inserted()) {
return fallback_id;
}
}
}
private:
SourceGen* gen_;
llvm::SmallVectorImpl<llvm::StringRef>* data_;
llvm::SmallVectorImpl<llvm::StringRef>::reverse_iterator it_;
const Set<llvm::StringRef>* excluded_;
Set<llvm::StringRef> set_;
};
// Emits a parameter list, wrapping it as declarations do. Carbon methods begin
// with `self`.
auto SourceGen::EmitParams(bool is_method, llvm::ArrayRef<TypedName> params,
llvm::StringRef indent, llvm::raw_ostream& os)
-> void {
if (static_cast<int>(params.size()) >
(is_method ? NumSingleLineMethodParams : NumSingleLineFunctionParams)) {
os << "\n" << indent << " ";
}
// For Carbon methods, `self` is the first explicit parameter. Its type is
// omitted, which defaults it to `Self`.
bool is_carbon_method = is_method && !IsCpp();
if (is_carbon_method) {
os << "self";
}
for (auto [i, param] : llvm::enumerate(params)) {
// `self` occupies the first slot for Carbon methods, so shift the index
// used for separators and line wrapping.
int slot = static_cast<int>(i) + (is_carbon_method ? 1 : 0);
if (slot > 0) {
if ((slot % MaxParamsPerLine) == 0) {
os << ",\n" << indent << " ";
} else {
os << ", ";
}
}
if (!IsCpp()) {
os << param.name << ": " << param.type;
} else {
os << param.type << " " << param.name;
}
}
}
// Emits a function declaration with the given signature.
auto SourceGen::EmitFunctionDecl(llvm::StringRef name, bool is_private,
bool is_method,
llvm::ArrayRef<TypedName> params,
llvm::StringRef return_type,
llvm::StringRef indent, llvm::raw_ostream& os)
-> void {
os << indent << "// TODO: make better comment text\n";
if (!IsCpp()) {
os << indent << (is_private ? "private " : "") << "fn " << name;
} else {
os << indent;
if (!is_method) {
os << "static ";
}
os << "auto " << name;
}
os << "(";
EmitParams(is_method, params, indent, os);
os << ") -> " << return_type << ";\n";
}
// Generates a function declaration and writes it to the provided stream.
//
// The declaration can be configured with a function name, private modifier,
// whether it is a method, the parameter count, and how indented it is. Its
// parameter names and types come from `state`. When `captured` is not null, the
// declaration has an out-of-line definition, and records its signature in
// `captured`.
auto SourceGen::GenerateFunctionDecl(ClassGenState& state, llvm::StringRef name,
bool is_private, bool is_method,
int param_count, llvm::StringRef indent,
llvm::raw_ostream& os,
FunctionSig* captured) -> void {
bool out_of_line = captured != nullptr;
// Add the extra parameter; see `BuildClassAndTypeNames`.
if (out_of_line) {
param_count += 1;
}
// Exclude class names so that a parameter can't shadow a class that an
// out-of-line definition names.
UniqueIdentifierPopper unique_param_names(*this, state.param_names(),
&state.class_name_set());
FunctionSig sig = {.name = name, .is_method = is_method};
sig.params.reserve(param_count);
sig.param_consumers.reserve(param_count);
for (auto _ : llvm::seq(param_count)) {
llvm::StringRef param = unique_param_names.Pop();
ClassGenState::TypeUse type =
out_of_line ? state.GetOutOfLineParamType() : state.GetDeclType();
sig.params.push_back({.name = param, .type = type.name});
sig.param_consumers.push_back(type.consumer);
}
ClassGenState::TypeUse return_type =
out_of_line ? state.GetOutOfLineReturnType() : state.GetDeclType();
sig.return_type = return_type.name;
sig.def_plan = return_type.index;
EmitFunctionDecl(name, is_private, is_method, sig.params, sig.return_type,
indent, os);
if (captured) {
*captured = std::move(sig);
}
}
// Emits `format` with `name` substituted for its `{0}`.
static auto EmitTemplate(llvm::StringRef format, llvm::StringRef name,
llvm::raw_ostream& os) -> void {
CARBON_CHECK(!format.empty());
auto [prefix, suffix] = format.split("{0}");
os << prefix << name << suffix;
}
// A statement of an arranged definition. A statement that opens blocks opens
// them at `first_block` and, for a second block, the index after it.
struct ArrangedStmt {
PlanStmt plan;
int first_block = -1;
};
// A block of an arranged definition.
struct ArrangedBlock {
// Indices into `ArrangedDef::stmts`.
llvm::SmallVector<int> stmts;
bool is_loop_block = false;
};
// A definition plan's statements, arranged in blocks. The first block is the
// definition's top-level block.
struct ArrangedDef {
llvm::SmallVector<ArrangedStmt> stmts;
llvm::SmallVector<ArrangedBlock> blocks;
};
// Randomly arranges the statements of `plan`, along with a `ReadParams`
// statement at depth 0. Each block gets at least one statement, and ends with a
// statement that isn't a local, so that the statement after each local can read
// it. Guard exits go in distinct loop blocks.
//
// The statements beyond the first in each block go in a block chosen with
// probability proportional to its statements so far, counting loop blocks
// `LoopBlockWeight` times. This gives a wider spread of block sizes than
// choosing uniformly, and larger loop blocks, as in real definitions.
static auto ArrangeDef(const DefPlan& plan, absl::BitGen& rng) -> ArrangedDef {
ArrangedDef def;
def.blocks.emplace_back();
llvm::SmallVector<int> level_blocks = {0};
int num_depths = std::max<int>(plan.levels.size(), 1);
for (int depth : llvm::seq(num_depths)) {
llvm::SmallVector<PlanStmt> exits;
llvm::SmallVector<PlanStmt> others;
llvm::SmallVector<PlanStmt> locals;
if (depth < static_cast<int>(plan.levels.size())) {
for (PlanStmt stmt : plan.levels[depth]) {
switch (stmt.kind) {
case PlanKind::GuardExit:
exits.push_back(stmt);
break;
case PlanKind::Local:
locals.push_back(stmt);
break;
default:
others.push_back(stmt);
break;
}
}
}
if (depth == 0) {
others.push_back({.kind = PlanKind::ReadParams, .spelling_index = 0});
}
std::shuffle(others.begin(), others.end(), rng);
// The block of each statement placed at this depth.
llvm::SmallVector<int> placed_blocks;
auto place = [&](int block, PlanStmt stmt) {
def.blocks[block].stmts.push_back(def.stmts.size());
def.stmts.push_back({.plan = stmt});
placed_blocks.push_back(block);
};
llvm::SmallVector<int> loop_blocks;
for (int block : level_blocks) {
if (def.blocks[block].is_loop_block) {
loop_blocks.push_back(block);
}
}
CARBON_CHECK(exits.size() <= loop_blocks.size());
std::shuffle(loop_blocks.begin(), loop_blocks.end(), rng);
for (auto [block, exit] : llvm::zip(loop_blocks, exits)) {
place(block, exit);
}
for (int block : level_blocks) {
if (def.blocks[block].stmts.empty()) {
CARBON_CHECK(!others.empty(), "Not enough statements to end blocks.");
place(block, others.pop_back_val());
}
}
for (int block : loop_blocks) {
placed_blocks.append(LoopBlockWeight - 1, block);
}
for (PlanStmt stmt : llvm::concat<PlanStmt>(others, locals)) {
int block =
placed_blocks[absl::Uniform<int>(rng, 0, placed_blocks.size())];
place(block, stmt);
if (def.blocks[block].is_loop_block) {
placed_blocks.append(LoopBlockWeight - 1, block);
}
}
for (int block : level_blocks) {
llvm::SmallVector<int>& stmts = def.blocks[block].stmts;
std::shuffle(stmts.begin(), stmts.end(), rng);
auto is_local = [&](int stmt) {
return def.stmts[stmt].plan.kind == PlanKind::Local;
};
if (is_local(stmts.back())) {
llvm::SmallVector<int> non_locals;
for (int i : llvm::seq<int>(stmts.size())) {
if (!is_local(stmts[i])) {
non_locals.push_back(i);
}
}
std::swap(
stmts.back(),
stmts[non_locals[absl::Uniform<int>(rng, 0, non_locals.size())]]);
}
}
// Open the blocks for the next depth.
llvm::SmallVector<int> next_blocks;
for (int block : level_blocks) {
for (int i : llvm::seq<int>(def.blocks[block].stmts.size())) {
ArrangedStmt& stmt = def.stmts[def.blocks[block].stmts[i]];
int num_blocks = NumPlanBlocks(stmt.plan.kind);
if (num_blocks == 0) {
continue;
}
stmt.first_block = def.blocks.size();
for (auto _ : llvm::seq(num_blocks)) {
next_blocks.push_back(def.blocks.size());
def.blocks.push_back(
{.is_loop_block = stmt.plan.kind == PlanKind::While});
}
}
}
level_blocks = std::move(next_blocks);
}
CARBON_CHECK(level_blocks.empty());
return def;
}
// Emits the statements of `def` after the accumulator declaration that every
// function begins with, indented beyond `indent`. Locals take their names from
// `locals` in turn, the `ReadParams` statement adds `reads`, and guards return
// `return_value`.
//
// The first operand of each statement after a local is that local, so that
// every local is read. Every other operand, and the target of each update, is a
// random local in scope.
static auto EmitArrangedDef(const ArrangedDef& def,
llvm::ArrayRef<llvm::StringRef> locals,
llvm::StringRef reads, llvm::StringRef return_value,
bool is_cpp, llvm::StringRef indent,
absl::BitGen& rng, llvm::raw_ostream& os) -> void {
llvm::SmallVector<llvm::StringRef> scope = {"acc"};
llvm::StringRef pending = "acc";
int next_local = 0;
auto pick_local = [&]() {
return scope[absl::Uniform<int>(rng, 0, scope.size())];
};
auto emit_expr = [&](llvm::StringRef format) {
while (!format.empty()) {
if (format.starts_with("{0}") || format.starts_with("{1}")) {
os << (pending.empty() ? pick_local() : std::exchange(pending, {}));
format = format.drop_front(3);
} else {
os << format.front();
format = format.drop_front();
}
}
};
auto emit_cond = [&](int spelling_index) {
emit_expr(PlanConds[spelling_index % std::size(PlanConds)]);
};
auto indent_to = [&](int depth) {
os << indent;
os.indent(2 * depth);
};
// The blocks being emitted, with the index of the next statement in each,
// and the size of the scope outside it.
struct Frame {
int block;
int next_stmt;
int outer_scope_size;
};
llvm::SmallVector<Frame> stack = {
{.block = 0, .next_stmt = 0, .outer_scope_size = 1}};
while (!stack.empty()) {
Frame& frame = stack.back();
int depth = stack.size();
const ArrangedBlock& block = def.blocks[frame.block];
if (frame.next_stmt == static_cast<int>(block.stmts.size())) {
// End the block, and start the second block of an `else` or `else if`.
scope.truncate(frame.outer_scope_size);
int ended = frame.block;
stack.pop_back();
if (stack.empty()) {
break;
}
const Frame& owner_frame = stack.back();
const ArrangedStmt& owner =
def.stmts[def.blocks[owner_frame.block]
.stmts[owner_frame.next_stmt - 1]];
indent_to(depth - 1);
if (NumPlanBlocks(owner.plan.kind) == 1 || ended != owner.first_block) {
os << "}\n";
continue;
}
if (owner.plan.kind == PlanKind::IfElse) {
os << "} else {\n";
} else {
os << "} else if (";
emit_cond(owner.plan.spelling_index + 1);
os << ") {\n";
}
stack.push_back({.block = ended + 1,
.next_stmt = 0,
.outer_scope_size = static_cast<int>(scope.size())});
continue;
}
const ArrangedStmt& stmt = def.stmts[block.stmts[frame.next_stmt]];
++frame.next_stmt;
PlanStmt planned = stmt.plan;
indent_to(depth);
switch (planned.kind) {
case PlanKind::Local: {
llvm::StringRef name = locals[next_local++];
os << (is_cpp ? "int " : "var ") << name
<< (is_cpp ? " = " : ": i32 = ");
emit_expr(PlanExprs[planned.spelling_index]);
os << ";\n";
scope.push_back(name);
pending = name;
break;
}
case PlanKind::Update:
os << pick_local() << " = ";
emit_expr(PlanExprs[planned.spelling_index]);
os << ";\n";
break;
case PlanKind::ReadParams:
os << pick_local() << " = ";
emit_expr("{0}");
os << " + " << reads << ";\n";
break;
case PlanKind::If:
case PlanKind::IfElse:
case PlanKind::ElseIf:
case PlanKind::While:
os << (planned.kind == PlanKind::While ? "while (" : "if (");
emit_cond(planned.spelling_index);
os << ") {\n";
stack.push_back({.block = stmt.first_block,
.next_stmt = 0,
.outer_scope_size = static_cast<int>(scope.size())});
break;
case PlanKind::GuardReturn:
case PlanKind::GuardExit:
os << "if (";
emit_cond(planned.spelling_index);
os << ") {\n";
indent_to(depth + 1);
if (planned.kind == PlanKind::GuardReturn) {
os << "return " << return_value << ";\n";
} else {
os << (planned.spelling_index % 2 == 0 ? "break;\n" : "continue;\n");
}
indent_to(depth);
os << "}\n";
break;
}
}
}
// Generates the statements of a plan-based function or method definition (used
// for both `inline_function_defs` and out-of-line definitions) with signature
// `sig`, from its `acc` declaration through its `return`, indented beyond
// `indent`.
//
// Unlike the single-expression member idioms (`GenerateGetter`,
// `GeneratePredicate`, and `GenerateForwarder`), which have fixed signatures
// coupled to a class field or private `<name>Impl` declaration, a plan-based
// definition works with any `FunctionSig`: after declaring `acc`, it arranges
// its `DefPlan` statements randomly along with a depth-0 statement that reads
// every parameter with its consumer template (and `self` in a method with
// `Checksum`), and ends with `return`. That parameter-read statement is on one
// line however long it is, which the line estimates assume.
auto SourceGen::GenerateFunctionDef(ClassGenState& state,
const FunctionSig& sig,
llvm::StringRef indent,
llvm::raw_ostream& os) -> void {
os << indent << (IsCpp() ? " int acc = 0;\n" : " var acc: i32 = 0;\n");
RawStringOstream reads;
llvm::ListSeparator read_sep(" + ");
if (sig.is_method) {
reads << read_sep << (IsCpp() ? "Checksum()" : "self.Checksum()");
}
for (auto [param, consumer] : llvm::zip(sig.params, sig.param_consumers)) {
reads << read_sep;
EmitTemplate(consumer, param.name, reads);
}
// Locals and parameters draw from the same identifiers of each length, so
// exclude this function's parameter names: C++ rejects a local that
// has the same name as a parameter.
const DefPlan& plan = state.def_plans()[sig.def_plan];
Set<llvm::StringRef> param_names;
for (const TypedName& param : sig.params) {
param_names.Insert(param.name);
}
UniqueIdentifierPopper unique_local_names(*this, state.local_names(),
&param_names);
llvm::SmallVector<llvm::StringRef> locals;
locals.reserve(plan.locals);
for (auto _ : llvm::seq(plan.locals)) {
locals.push_back(unique_local_names.Pop());
}
RawStringOstream return_value;
state.ProduceValue(sig.return_type, return_value);
std::string return_value_str = return_value.TakeStr();
EmitArrangedDef(ArrangeDef(plan, rng_), locals, reads.TakeStr(),
return_value_str, IsCpp(), indent, rng_, os);
os << indent << " return " << return_value_str << ";\n";
}
// Generates an out-of-line definition for the declaration `sig`, and writes it
// to the provided stream. The signature is on one line however long it is,
// which the line estimates assume.
auto SourceGen::GenerateOutOfLineDef(ClassGenState& state,
llvm::StringRef class_name,
const FunctionSig& sig,
llvm::raw_ostream& os) -> void {
os << "// TODO: make better comment text\n";
if (!IsCpp()) {
os << "fn " << class_name << "." << sig.name;
} else {
os << "auto " << class_name << "::" << sig.name;
}
os << "(";
// For Carbon methods, `self` is the first parameter, as in the declaration.
bool is_carbon_method = sig.is_method && !IsCpp();
if (is_carbon_method) {
os << "self";
}
bool first_param = !is_carbon_method;
for (const TypedName& param : sig.params) {
if (!first_param) {
os << ", ";
}
first_param = false;
if (!IsCpp()) {
os << param.name << ": " << param.type;
} else {
os << param.type << " " << param.name;
}
}
os << ") -> " << sig.return_type << " {\n";
GenerateFunctionDef(state, sig, /*indent=*/"", os);
os << "}\n";
}
// Generates an inline function definition and writes it to the provided
// stream. Its statements follow the plan paired with its return type; see
// `GenerateFunctionDef`.
auto SourceGen::GenerateInlineFunctionDef(ClassGenState& state,
llvm::StringRef name, int param_count,
llvm::StringRef indent,
llvm::raw_ostream& os) -> void {
// Add the extra parameter; see `BuildClassAndTypeNames`.
param_count += 1;
// Exclude class names so that a parameter can't shadow a class that the
// definition names.
UniqueIdentifierPopper unique_param_names(*this, state.inline_param_names(),
&state.class_name_set());
FunctionSig sig = {.name = name, .is_method = false};
sig.params.reserve(param_count);
sig.param_consumers.reserve(param_count);
for (auto _ : llvm::seq(param_count)) {
llvm::StringRef param = unique_param_names.Pop();
ClassGenState::TypeUse type = state.GetInlineParamType();
sig.params.push_back({.name = param, .type = type.name});
sig.param_consumers.push_back(type.consumer);
}
ClassGenState::TypeUse return_type = state.GetInlineReturnType();
sig.return_type = return_type.name;
sig.def_plan = state.inline_def_plans_start() + return_type.index;
os << indent << "// TODO: make better comment text\n";
os << indent << (IsCpp() ? "static auto " : "fn ") << name << "(";
EmitParams(/*is_method=*/false, sig.params, indent, os);
os << ") -> " << sig.return_type << " {\n";
GenerateFunctionDef(state, sig, indent, os);
os << indent << "}\n";
}
// Generates an inline method that returns `field`.
auto SourceGen::GenerateGetter(llvm::StringRef name, TypedName field,
llvm::raw_ostream& os) -> void {
os << " // TODO: make better comment text\n";
if (!IsCpp()) {
os << " fn " << name << "(self) -> " << field.type << " { return self."
<< field.name << "; }\n";
} else {
os << " auto " << name << "() const -> " << field.type << " { return "
<< field.name << "; }\n";
}
}
// Generates an inline method that returns the `predicate` template applied to
// `field`.
auto SourceGen::GeneratePredicate(llvm::StringRef name, TypedName field,
llvm::StringRef predicate,
llvm::raw_ostream& os) -> void {
os << " // TODO: make better comment text\n";
if (!IsCpp()) {
os << " fn " << name << "(self) -> bool { return ";
EmitTemplate(predicate, ("self." + field.name).str(), os);
} else {
os << " auto " << name << "() const -> bool { return ";
EmitTemplate(predicate, field.name, os);
}
os << "; }\n";
}
// Generates an inline method that passes its parameters on to `<name>Impl`, a
// private method with the same signature.
auto SourceGen::GenerateForwarder(llvm::StringRef name,
llvm::ArrayRef<TypedName> params,
llvm::StringRef return_type,
llvm::raw_ostream& os) -> void {
os << " // TODO: make better comment text\n";
os << " " << (IsCpp() ? "auto " : "fn ") << name << "(";
EmitParams(/*is_method=*/true, params, /*indent=*/" ", os);
os << ") -> " << return_type << " {\n";
os << " return " << (IsCpp() ? "" : "self.") << name << "Impl(";
llvm::ListSeparator sep;
for (const TypedName& param : params) {
os << sep << param.name;
}
os << ");\n }\n";
}
// Generates a class's `Make` function, which returns a value of the class with
// every field initialized. C++ classes idiomatically initialize with a
// constructor, so C++ gets a default constructor with the same initializers. A
// class-typed field calls an earlier class's `Make`, so these calls never
// recurse.
auto SourceGen::GenerateMakeFunction(ClassGenState& state,
llvm::StringRef class_name,
llvm::ArrayRef<TypedName> fields,
llvm::raw_ostream& os) -> void {
os << " // TODO: make better comment text\n";
if (IsCpp()) {
os << " " << class_name << "()\n";
os << " : tag(0)";
for (const TypedName& field : fields) {
os << ", " << field.name << "(";
state.ProduceValue(field.type, os);
os << ")";
}
os << " {}\n";
return;
}
os << " fn Make() -> " << class_name << " {\n";
os << " return {.tag = 0";
for (const TypedName& field : fields) {
os << ", ." << field.name << " = ";
state.ProduceValue(field.type, os);
}
os << "};\n }\n";
}
// Generates a class's `Checksum` method, which the class consumer templates
// call to read a value of the class. It reads only `tag`, so it is the same in
// every class without needing consumer expressions for the other fields.
auto SourceGen::GenerateChecksumFunction(llvm::raw_ostream& os) -> void {
os << " // TODO: make better comment text\n";
if (!IsCpp()) {
os << " fn Checksum(self) -> i32 {\n";
os << " return self.tag + 1;\n";
} else {
os << " auto Checksum() -> int {\n";
os << " return tag + 1;\n";
}
os << " }\n";
}
// Generate a class definition and write it to the provided stream.
//
// The structure of the definition is guided by the `params` provided, and it
// consumes the provided state. With out-of-line definitions, it appends the
// declarations to define to `out_of_line_defs`.
auto SourceGen::GenerateClassDef(
const ClassParams& params, ClassGenState& state, llvm::raw_ostream& os,
llvm::SmallVectorImpl<OutOfLineDef>& out_of_line_defs) -> void {
llvm::StringRef name = state.class_names().pop_back_val();
os << "// TODO: make better comment text\n";
os << "class " << name << " {\n";
if (IsCpp()) {
os << " public:\n";
}
// Field types can't be the class we're currently declaring. We enforce this
// by collecting them before inserting that type into the valid set.
llvm::SmallVector<llvm::StringRef> field_type_names;
field_type_names.reserve(params.private_field_decls);
for (auto _ : llvm::seq(params.private_field_decls)) {
field_type_names.push_back(state.GetFieldType().name);
}
// Mark this class as now a valid type now that field type names have been
// collected. We can reference this class from functions and methods within
// the definition.
state.AddValidTypeName(name);
// Name the getter and predicate fields first, so that member names can avoid
// them.
UniqueIdentifierPopper unique_accessed_names(
*this, state.accessed_field_names(), &state.class_name_set());
llvm::SmallVector<TypedName> getter_fields;
getter_fields.reserve(params.inline_getters);
for (auto _ : llvm::seq(params.inline_getters)) {
getter_fields.push_back(
{.name = unique_accessed_names.Pop(),
.type = state.getter_field_types().pop_back_val()});
}
llvm::SmallVector<std::pair<TypedName, llvm::StringRef>> predicate_fields;
predicate_fields.reserve(params.inline_predicates);
for (auto _ : llvm::seq(params.inline_predicates)) {
ClassGenState::PredicateField field =
state.predicate_fields().pop_back_val();
predicate_fields.push_back(
{{.name = unique_accessed_names.Pop(), .type = field.type},
field.predicate});
}
// Definitions in this class can name any class, so exclude class names from
// member names. Inline function names are too short to be class names.
UniqueIdentifierPopper unique_member_names(*this, state.decl_names(),
&state.class_name_set());
unique_member_names.Reserve(unique_accessed_names.used());
UniqueIdentifierPopper unique_inline_names(*this,
state.inline_function_names());
// Capture each declaration's signature for its out-of-line definition.
bool define_out_of_line = state.define_decls_out_of_line();
auto capture_sig = [&]() -> FunctionSig* {
if (!define_out_of_line) {
return nullptr;
}
return &out_of_line_defs.emplace_back(OutOfLineDef{.class_name = name}).sig;
};
llvm::ListSeparator line_sep("\n");
for (auto _ : llvm::seq(params.public_function_decls)) {
os << line_sep;
GenerateFunctionDecl(state, unique_member_names.Pop(), /*is_private=*/false,
/*is_method=*/false,
state.public_function_param_counts().pop_back_val(),
/*indent=*/" ", os, capture_sig());
}
for (auto _ : llvm::seq(params.inline_function_defs)) {
os << line_sep;
GenerateInlineFunctionDef(
state, unique_inline_names.Pop(),
state.inline_function_param_counts().pop_back_val(), /*indent=*/" ",
os);
}
for (auto _ : llvm::seq(params.public_method_decls)) {
os << line_sep;
GenerateFunctionDecl(state, unique_member_names.Pop(), /*is_private=*/false,
/*is_method=*/true,
state.public_method_param_counts().pop_back_val(),
/*indent=*/" ", os, capture_sig());
}
for (TypedName field : getter_fields) {
os << line_sep;
GenerateGetter(unique_inline_names.Pop(), field, os);
}
for (auto [field, predicate] : predicate_fields) {
os << line_sep;
GeneratePredicate(unique_inline_names.Pop(), field, predicate, os);
}
// Forwarder names are as short as other inline function names, so exclude
// those.
UniqueIdentifierPopper unique_forwarder_names(*this, state.forwarder_names());
unique_forwarder_names.Reserve(unique_inline_names.used());
struct Forwarder {
llvm::StringRef name;
llvm::SmallVector<TypedName> params;
llvm::StringRef return_type;
};
llvm::SmallVector<Forwarder> forwarders;
forwarders.reserve(params.inline_forwarders);
for (auto _ : llvm::seq(params.inline_forwarders)) {
Forwarder& forwarder = forwarders.emplace_back();
forwarder.name = unique_forwarder_names.Pop();
// Exclude class names so that a parameter can't shadow a class in the
// signature.
UniqueIdentifierPopper unique_param_names(
*this, state.forwarder_param_names(), &state.class_name_set());
for (auto _ : llvm::seq(state.forwarder_param_counts().pop_back_val())) {
forwarder.params.push_back({.name = unique_param_names.Pop(),
.type = state.GetForwardType().name});
}
forwarder.return_type = state.GetForwardType().name;
os << line_sep;
GenerateForwarder(forwarder.name, forwarder.params, forwarder.return_type,
os);
}
if (IsCpp()) {
os << "\n private:\n";
// Reset the separator.
line_sep = llvm::ListSeparator("\n");
}
for (auto _ : llvm::seq(params.private_function_decls)) {
os << line_sep;
GenerateFunctionDecl(state, unique_member_names.Pop(), /*is_private=*/true,
/*is_method=*/false,
state.private_function_param_counts().pop_back_val(),
/*indent=*/" ", os, capture_sig());
}
for (auto _ : llvm::seq(params.private_method_decls)) {
os << line_sep;
GenerateFunctionDecl(state, unique_member_names.Pop(), /*is_private=*/true,
/*is_method=*/true,
state.private_method_param_counts().pop_back_val(),
/*indent=*/" ", os, capture_sig());
}
for (const Forwarder& forwarder : forwarders) {
os << line_sep;
EmitFunctionDecl((forwarder.name + "Impl").str(), /*is_private=*/true,
/*is_method=*/true, forwarder.params,
forwarder.return_type, /*indent=*/" ", os);
}
// Field names can't repeat this class's function, method, or field names, or
// be a class name.
UniqueIdentifierPopper unique_field_names(*this, state.field_names(),
&state.class_name_set());
unique_field_names.Reserve(unique_member_names.used());
llvm::SmallVector<TypedName> fields;
fields.reserve(field_type_names.size() + getter_fields.size() +
predicate_fields.size());
for (llvm::StringRef type_name : field_type_names) {
fields.push_back({.name = unique_field_names.Pop(), .type = type_name});
}
llvm::append_range(fields, getter_fields);
for (auto [field, _] : predicate_fields) {
fields.push_back(field);
}
// With definitions, C++ puts `Make` and `Checksum` in a second public
// section, followed by a private section for the fields.
bool has_defs = state.has_defs();
if (IsCpp() && has_defs) {
os << "\n public:\n";
line_sep = llvm::ListSeparator("\n");
}
// Only definitions call `Make` and `Checksum`.
if (has_defs) {
os << line_sep;
GenerateMakeFunction(state, name, fields, os);
os << line_sep;
GenerateChecksumFunction(os);
if (IsCpp()) {
os << "\n private:\n";
line_sep = llvm::ListSeparator("\n");
}
}
os << line_sep;
// `tag` comes first, matching its position in `Make`.
if (has_defs) {
os << (IsCpp() ? " int tag;\n" : " private var tag: i32;\n");
}
for (const TypedName& field : fields) {
if (!IsCpp()) {
os << " private var " << field.name << ": " << field.type << ";\n";
} else {
os << " " << field.type << " " << field.name << ";\n";
}
}
os << "}" << (IsCpp() ? ";" : "") << "\n";
}
} // namespace Carbon::Testing
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