Files
carbon-lang/toolchain/check/node_stack.h
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2023-12-08 23:35:47 +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
#ifndef CARBON_TOOLCHAIN_CHECK_NODE_STACK_H_
#define CARBON_TOOLCHAIN_CHECK_NODE_STACK_H_
#include <type_traits>
#include "common/vlog.h"
#include "llvm/ADT/SmallVector.h"
#include "toolchain/parse/node_kind.h"
#include "toolchain/parse/tree.h"
#include "toolchain/sem_ir/inst.h"
namespace Carbon::Check {
// Wraps the stack of parse nodes for Context. Each parse node can have an
// associated id of some kind (instruction, instruction block, function, class,
// ...).
//
// All pushes and pops will be vlogged.
//
// Pop APIs will run basic verification:
//
// - If receiving a pop_parse_kind, verify that the parse_node being popped is
// of pop_parse_kind.
// - Validates presence of inst_id based on whether it's a solo
// parse_node.
//
// These should be assumed API constraints unless otherwise mentioned on a
// method. The main exception is PopAndIgnore, which doesn't do verification.
class NodeStack {
public:
explicit NodeStack(const Parse::Tree& parse_tree,
llvm::raw_ostream* vlog_stream)
: parse_tree_(&parse_tree), vlog_stream_(vlog_stream) {}
// Pushes a solo parse tree node onto the stack. Used when there is no
// IR generated by the node.
auto Push(Parse::NodeId parse_node) -> void {
CARBON_CHECK(ParseNodeIdKind(parse_node) == IdKind::SoloParseNode)
<< "Parse kind expects an Id: " << parse_tree_->node_kind(parse_node);
CARBON_VLOG() << "Node Push " << stack_.size() << ": "
<< parse_tree_->node_kind(parse_node) << " -> <none>\n";
CARBON_CHECK(stack_.size() < (1 << 20))
<< "Excessive stack size: likely infinite loop";
stack_.push_back(Entry(parse_node, SemIR::InstId::Invalid));
}
// Pushes a parse tree node onto the stack with an ID.
template <typename IdT>
auto Push(Parse::NodeId parse_node, IdT id) -> void {
CARBON_CHECK(ParseNodeIdKind(parse_node) == IdTypeToIdKind<IdT>())
<< "Parse kind expected a different IdT: "
<< parse_tree_->node_kind(parse_node) << " -> " << id << "\n";
CARBON_CHECK(id.is_valid()) << "Push called with invalid id: "
<< parse_tree_->node_kind(parse_node);
CARBON_VLOG() << "Node Push " << stack_.size() << ": "
<< parse_tree_->node_kind(parse_node) << " -> " << id << "\n";
CARBON_CHECK(stack_.size() < (1 << 20))
<< "Excessive stack size: likely infinite loop";
stack_.push_back(Entry(parse_node, id));
}
// Returns whether the node on the top of the stack is the specified kind.
template <Parse::NodeKind::RawEnumType RequiredParseKind>
auto PeekIs() const -> bool {
return !stack_.empty() &&
parse_tree_->node_kind(PeekParseNode()) == RequiredParseKind;
}
// Returns whether the node on the top of the stack is a name.
auto PeekIsName() const -> bool {
return !stack_.empty() &&
ParseNodeIdKind(PeekParseNode()) == IdKind::NameId;
}
// Pops the top of the stack without any verification.
auto PopAndIgnore() -> void { PopEntry<SemIR::InstId>(); }
// Pops the top of the stack and returns the parse_node.
template <Parse::NodeKind::RawEnumType RequiredParseKind>
auto PopForSoloParseNode() -> Parse::NodeId {
Entry back = PopEntry<SemIR::InstId>();
RequireIdKind(Parse::NodeKind::Create(RequiredParseKind),
IdKind::SoloParseNode);
RequireParseKind<RequiredParseKind>(back.parse_node);
return back.parse_node;
}
// Pops the top of the stack if it is the given kind, and returns the
// parse_node. Otherwise, returns std::nullopt.
template <Parse::NodeKind::RawEnumType RequiredParseKind>
auto PopForSoloParseNodeIf() -> std::optional<Parse::NodeId> {
if (PeekIs<RequiredParseKind>()) {
return PopForSoloParseNode<RequiredParseKind>();
}
return std::nullopt;
}
// Pops the top of the stack.
template <Parse::NodeKind::RawEnumType RequiredParseKind>
auto PopAndDiscardSoloParseNode() -> void {
PopForSoloParseNode<RequiredParseKind>();
}
// Pops the top of the stack if it is the given kind. Returns `true` if a node
// was popped.
template <Parse::NodeKind::RawEnumType RequiredParseKind>
auto PopAndDiscardSoloParseNodeIf() -> bool {
if (!PeekIs<RequiredParseKind>()) {
return false;
}
PopForSoloParseNode<RequiredParseKind>();
return true;
}
// Pops an expression from the top of the stack and returns the parse_node and
// the ID.
auto PopExprWithParseNode() -> std::pair<Parse::NodeId, SemIR::InstId> {
return PopWithParseNode<SemIR::InstId>();
}
// Pops a name from the top of the stack and returns the parse_node and
// the ID.
auto PopNameWithParseNode() -> std::pair<Parse::NodeId, SemIR::NameId> {
return PopWithParseNode<SemIR::NameId>();
}
// Pops the top of the stack and returns the parse_node and the ID.
template <Parse::NodeKind::RawEnumType RequiredParseKind>
auto PopWithParseNode() -> auto {
constexpr IdKind RequiredIdKind =
ParseNodeKindToIdKind(Parse::NodeKind::Create(RequiredParseKind));
if constexpr (RequiredIdKind == IdKind::InstId) {
auto back = PopWithParseNode<SemIR::InstId>();
RequireParseKind<RequiredParseKind>(back.first);
return back;
}
if constexpr (RequiredIdKind == IdKind::InstBlockId) {
auto back = PopWithParseNode<SemIR::InstBlockId>();
RequireParseKind<RequiredParseKind>(back.first);
return back;
}
if constexpr (RequiredIdKind == IdKind::FunctionId) {
auto back = PopWithParseNode<SemIR::FunctionId>();
RequireParseKind<RequiredParseKind>(back.first);
return back;
}
if constexpr (RequiredIdKind == IdKind::ClassId) {
auto back = PopWithParseNode<SemIR::ClassId>();
RequireParseKind<RequiredParseKind>(back.first);
return back;
}
if constexpr (RequiredIdKind == IdKind::InterfaceId) {
auto back = PopWithParseNode<SemIR::InterfaceId>();
RequireParseKind<RequiredParseKind>(back.first);
return back;
}
if constexpr (RequiredIdKind == IdKind::NameId) {
auto back = PopWithParseNode<SemIR::NameId>();
RequireParseKind<RequiredParseKind>(back.first);
return back;
}
if constexpr (RequiredIdKind == IdKind::TypeId) {
auto back = PopWithParseNode<SemIR::TypeId>();
RequireParseKind<RequiredParseKind>(back.first);
return back;
}
CARBON_FATAL() << "Unpoppable IdKind for parse kind: "
<< Parse::NodeKind::Create(RequiredParseKind)
<< "; see value in ParseNodeKindToIdKind";
}
// Pops an expression from the top of the stack and returns the ID.
// Expressions map multiple Parse::NodeKinds to SemIR::InstId always.
auto PopExpr() -> SemIR::InstId { return PopExprWithParseNode().second; }
// Pops a name from the top of the stack and returns the ID.
auto PopName() -> SemIR::NameId { return PopNameWithParseNode().second; }
// Pops the top of the stack and returns the ID.
template <Parse::NodeKind::RawEnumType RequiredParseKind>
auto Pop() -> auto {
return PopWithParseNode<RequiredParseKind>().second;
}
// Pops the top of the stack if it has the given kind, and returns the ID.
// Otherwise returns std::nullopt.
template <Parse::NodeKind::RawEnumType RequiredParseKind>
auto PopIf() -> std::optional<decltype(Pop<RequiredParseKind>())> {
if (PeekIs<RequiredParseKind>()) {
return Pop<RequiredParseKind>();
}
return std::nullopt;
}
// Peeks at the parse node of the top of the name stack.
auto PeekParseNode() const -> Parse::NodeId {
return stack_.back().parse_node;
}
// Peeks at the ID associated with the top of the name stack.
template <Parse::NodeKind::RawEnumType RequiredParseKind>
auto Peek() const -> auto {
Entry back = stack_.back();
RequireParseKind<RequiredParseKind>(back.parse_node);
constexpr IdKind RequiredIdKind =
ParseNodeKindToIdKind(Parse::NodeKind::Create(RequiredParseKind));
if constexpr (RequiredIdKind == IdKind::InstId) {
return back.id<SemIR::InstId>();
}
if constexpr (RequiredIdKind == IdKind::InstBlockId) {
return back.id<SemIR::InstBlockId>();
}
if constexpr (RequiredIdKind == IdKind::FunctionId) {
return back.id<SemIR::FunctionId>();
}
if constexpr (RequiredIdKind == IdKind::ClassId) {
return back.id<SemIR::ClassId>();
}
if constexpr (RequiredIdKind == IdKind::InterfaceId) {
return back.id<SemIR::InterfaceId>();
}
if constexpr (RequiredIdKind == IdKind::NameId) {
return back.id<SemIR::NameId>();
}
if constexpr (RequiredIdKind == IdKind::TypeId) {
return back.id<SemIR::TypeId>();
}
CARBON_FATAL() << "Unpeekable IdKind for parse kind: "
<< Parse::NodeKind::Create(RequiredParseKind)
<< "; see value in ParseNodeKindToIdKind";
}
// Prints the stack for a stack dump.
auto PrintForStackDump(llvm::raw_ostream& output) const -> void;
auto empty() const -> bool { return stack_.empty(); }
auto size() const -> size_t { return stack_.size(); }
private:
// Possible associated ID types.
enum class IdKind : int8_t {
InstId,
InstBlockId,
FunctionId,
ClassId,
InterfaceId,
NameId,
TypeId,
// No associated ID type.
SoloParseNode,
// Not expected in the node stack.
Unused,
};
// An entry in stack_.
struct Entry {
explicit Entry(Parse::NodeId parse_node, SemIR::InstId inst_id)
: parse_node(parse_node), inst_id(inst_id) {}
explicit Entry(Parse::NodeId parse_node, SemIR::InstBlockId inst_block_id)
: parse_node(parse_node), inst_block_id(inst_block_id) {}
explicit Entry(Parse::NodeId parse_node, SemIR::FunctionId function_id)
: parse_node(parse_node), function_id(function_id) {}
explicit Entry(Parse::NodeId parse_node, SemIR::ClassId class_id)
: parse_node(parse_node), class_id(class_id) {}
explicit Entry(Parse::NodeId parse_node, SemIR::InterfaceId interface_id)
: parse_node(parse_node), interface_id(interface_id) {}
explicit Entry(Parse::NodeId parse_node, SemIR::NameId name_id)
: parse_node(parse_node), name_id(name_id) {}
explicit Entry(Parse::NodeId parse_node, SemIR::TypeId type_id)
: parse_node(parse_node), type_id(type_id) {}
// Returns the appropriate ID basaed on type.
template <typename T>
auto id() -> T& {
if constexpr (std::is_same<T, SemIR::InstId>()) {
return inst_id;
}
if constexpr (std::is_same<T, SemIR::InstBlockId>()) {
return inst_block_id;
}
if constexpr (std::is_same<T, SemIR::FunctionId>()) {
return function_id;
}
if constexpr (std::is_same<T, SemIR::ClassId>()) {
return class_id;
}
if constexpr (std::is_same<T, SemIR::InterfaceId>()) {
return interface_id;
}
if constexpr (std::is_same<T, SemIR::NameId>()) {
return name_id;
}
if constexpr (std::is_same<T, SemIR::TypeId>()) {
return type_id;
}
}
// The parse node associated with the stack entry.
Parse::NodeId parse_node;
// The entries will evaluate as invalid if and only if they're a solo
// parse_node. Invalid is used instead of optional to save space.
//
// A discriminator isn't needed because the caller can determine which field
// is used based on the Parse::NodeKind.
union {
SemIR::InstId inst_id;
SemIR::InstBlockId inst_block_id;
SemIR::FunctionId function_id;
SemIR::ClassId class_id;
SemIR::InterfaceId interface_id;
SemIR::NameId name_id;
SemIR::TypeId type_id;
};
};
static_assert(sizeof(Entry) == 8, "Unexpected Entry size");
// Translate a parse node kind to the enum ID kind it should always provide.
static constexpr auto ParseNodeKindToIdKind(Parse::NodeKind kind) -> IdKind {
switch (kind) {
case Parse::NodeKind::ArrayExpr:
case Parse::NodeKind::BindingPattern:
case Parse::NodeKind::CallExpr:
case Parse::NodeKind::CallExprStart:
case Parse::NodeKind::IdentifierNameExpr:
case Parse::NodeKind::IfExprThen:
case Parse::NodeKind::IfExprElse:
case Parse::NodeKind::IndexExpr:
case Parse::NodeKind::InfixOperator:
case Parse::NodeKind::MemberAccessExpr:
case Parse::NodeKind::PackageExpr:
case Parse::NodeKind::ParenExpr:
case Parse::NodeKind::PostfixOperator:
case Parse::NodeKind::PrefixOperator:
case Parse::NodeKind::ReturnType:
case Parse::NodeKind::SelfTypeNameExpr:
case Parse::NodeKind::SelfValueNameExpr:
case Parse::NodeKind::ShortCircuitOperand:
case Parse::NodeKind::StructFieldValue:
case Parse::NodeKind::StructLiteral:
case Parse::NodeKind::StructFieldType:
case Parse::NodeKind::StructTypeLiteral:
case Parse::NodeKind::TupleLiteral:
return IdKind::InstId;
case Parse::NodeKind::IfCondition:
case Parse::NodeKind::IfExprIf:
case Parse::NodeKind::ImplicitParamList:
case Parse::NodeKind::TuplePattern:
case Parse::NodeKind::WhileCondition:
case Parse::NodeKind::WhileConditionStart:
return IdKind::InstBlockId;
case Parse::NodeKind::FunctionDefinitionStart:
return IdKind::FunctionId;
case Parse::NodeKind::ClassDefinitionStart:
return IdKind::ClassId;
case Parse::NodeKind::InterfaceDefinitionStart:
return IdKind::InterfaceId;
case Parse::NodeKind::BaseName:
case Parse::NodeKind::IdentifierName:
return IdKind::NameId;
case Parse::NodeKind::ArrayExprSemi:
case Parse::NodeKind::ClassIntroducer:
case Parse::NodeKind::CodeBlockStart:
case Parse::NodeKind::ExprOpenParen:
case Parse::NodeKind::FunctionIntroducer:
case Parse::NodeKind::IfStatementElse:
case Parse::NodeKind::ImplicitParamListStart:
case Parse::NodeKind::InterfaceIntroducer:
case Parse::NodeKind::LetIntroducer:
case Parse::NodeKind::QualifiedDecl:
case Parse::NodeKind::ReturnedModifier:
case Parse::NodeKind::ReturnStatementStart:
case Parse::NodeKind::ReturnVarModifier:
case Parse::NodeKind::SelfValueName:
case Parse::NodeKind::StructLiteralOrStructTypeLiteralStart:
case Parse::NodeKind::TuplePatternStart:
case Parse::NodeKind::VariableInitializer:
case Parse::NodeKind::VariableIntroducer:
return IdKind::SoloParseNode;
// Use x-macros to handle token cases.
#define CARBON_PARSE_NODE_KIND(...)
#define CARBON_PARSE_NODE_KIND_TOKEN_LITERAL(Name, ...) \
case Parse::NodeKind::Name: \
return IdKind::InstId;
#define CARBON_PARSE_NODE_KIND_TOKEN_MODIFIER(Name, ...) \
case Parse::NodeKind::Name##Modifier: \
return IdKind::SoloParseNode;
#include "toolchain/parse/node_kind.def"
default:
return IdKind::Unused;
}
}
auto ParseNodeIdKind(Parse::NodeId node) const -> IdKind {
return ParseNodeKindToIdKind(parse_tree_->node_kind(node));
}
// Translates an ID type to the enum ID kind for comparison with
// ParseNodeKindToIdKind.
template <typename IdT>
static constexpr auto IdTypeToIdKind() -> IdKind {
if constexpr (std::is_same_v<IdT, SemIR::InstId>) {
return IdKind::InstId;
}
if constexpr (std::is_same_v<IdT, SemIR::InstBlockId>) {
return IdKind::InstBlockId;
}
if constexpr (std::is_same_v<IdT, SemIR::FunctionId>) {
return IdKind::FunctionId;
}
if constexpr (std::is_same_v<IdT, SemIR::ClassId>) {
return IdKind::ClassId;
}
if constexpr (std::is_same_v<IdT, SemIR::InterfaceId>) {
return IdKind::InterfaceId;
}
if constexpr (std::is_same_v<IdT, SemIR::NameId>) {
return IdKind::NameId;
}
if constexpr (std::is_same_v<IdT, SemIR::TypeId>) {
return IdKind::TypeId;
}
}
// Pops an entry.
template <typename IdT>
auto PopEntry() -> Entry {
Entry back = stack_.pop_back_val();
CARBON_VLOG() << "Node Pop " << stack_.size() << ": "
<< parse_tree_->node_kind(back.parse_node) << " -> "
<< back.id<IdT>() << "\n";
return back;
}
// Pops the top of the stack and returns the parse_node and the ID.
template <typename IdT>
auto PopWithParseNode() -> std::pair<Parse::NodeId, IdT> {
Entry back = PopEntry<IdT>();
RequireIdKind(parse_tree_->node_kind(back.parse_node),
IdTypeToIdKind<IdT>());
return {back.parse_node, back.id<IdT>()};
}
// Require a Parse::NodeKind be mapped to a particular IdKind.
auto RequireIdKind(Parse::NodeKind parse_kind, IdKind id_kind) const -> void {
CARBON_CHECK(ParseNodeKindToIdKind(parse_kind) == id_kind)
<< "Unexpected IdKind mapping for " << parse_kind;
}
// Require an entry to have the given Parse::NodeKind.
template <Parse::NodeKind::RawEnumType RequiredParseKind>
auto RequireParseKind(Parse::NodeId parse_node) const -> void {
auto actual_kind = parse_tree_->node_kind(parse_node);
CARBON_CHECK(RequiredParseKind == actual_kind)
<< "Expected " << Parse::NodeKind::Create(RequiredParseKind)
<< ", found " << actual_kind;
}
// The file's parse tree.
const Parse::Tree* parse_tree_;
// Whether to print verbose output.
llvm::raw_ostream* vlog_stream_;
// The actual stack.
// PushEntry and PopEntry control modification in order to centralize
// vlogging.
llvm::SmallVector<Entry> stack_;
};
} // namespace Carbon::Check
#endif // CARBON_TOOLCHAIN_CHECK_NODE_STACK_H_