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Add CARBON_KIND_SWITCH to better handle typed inst switches. (#3820)

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Converts a switch in formatter.cpp as an example of resulting syntax.
This commit is contained in:
Jon Ross-Perkins
2024-03-27 22:09:41 +00:00
committed by GitHub
parent c236ef400c
commit 2a6c5255fb
4 changed files with 141 additions and 45 deletions
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toolchain/base/BUILD
+8
View File
@@ -15,6 +15,14 @@ cc_library(
],
)
cc_library(
name = "kind_switch",
hdrs = ["kind_switch.h"],
deps = [
"@llvm-project//llvm:Support",
],
)
cc_library(
name = "pretty_stack_trace_function",
hdrs = ["pretty_stack_trace_function.h"],
toolchain/base/kind_switch.h
+93
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@@ -0,0 +1,93 @@
// 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_BASE_KIND_SWITCH_H_
#define CARBON_TOOLCHAIN_BASE_KIND_SWITCH_H_
#include "llvm/ADT/STLExtras.h"
// This library provides switch-like behaviors for Carbon's kind-based types.
//
// An expected use case is to mix regular switch `case` statements and
// `CARBON_KIND`. However, the `switch` must be defined using
// `CARBON_KIND_SWITCH`. For example:
//
// CARBON_KIND_SWITCH(untyped_inst) {
// case CARBON_KIND(SomeInstType inst): {
// return inst.typed_field;
// }
// case OtherType1::Kind:
// case OtherType2::Kind:
// return value;
// default:
// return default_value;
// }
//
// For compatibility, this requires:
//
// - The type passed to `CARBON_KIND_SWITCH` has `.kind()` to switch on, and
// `.As<CaseT>` for `CARBON_KIND` to cast to.
// - Each type passed to `CARBON_KIND` (`CaseT` above) provides
// `CaseT::Kind`, which is passed to the `case` keyword.
// `CaseT::Kind::RawEnumType` is the type returned by `.kind()`.
//
// Note, this is currently used primarily for Inst in toolchain. When more
// use-cases are added, it would be worth considering whether the API
// requirements should change.
namespace Carbon::Internal::Kind {
// Given `CARBON_KIND_SWITCH(value)` this handles calling `value.kind()`.
template <typename T>
auto SwitchOn(T&& switch_value) -> auto {
return switch_value.kind();
}
// Given `CARBON_KIND(CaseT name)` this generates `CaseT::Kind`. It explicitly
// returns `KindT` because that may differ from `CaseT::Kind`, and may not be
// copyable.
template <typename FnT>
consteval auto ForCase() -> auto {
using ArgT = llvm::function_traits<FnT>::template arg_t<0>;
return static_cast<decltype(ArgT::Kind)::RawEnumType>(ArgT::Kind);
}
// Given `CARBON_KIND_SWITCH(value)` and `CARBON_KIND(CaseT name)` this
// generates `value.As<CaseT>()`.
template <typename FnT, typename ValueT>
auto Cast(ValueT&& kind_switch_value) -> auto {
using CaseT = llvm::function_traits<FnT>::template arg_t<0>;
return kind_switch_value.template As<CaseT>();
}
#define CARBON_INTERNAL_KIND_MERGE(Prefix, Line) Prefix##Line
#define CARBON_INTERNAL_KIND_LABEL(Line) \
CARBON_INTERNAL_KIND_MERGE(carbon_internal_kind_case_, Line)
} // namespace Carbon::Internal::Kind
// Produces a switch statement on value.kind().
#define CARBON_KIND_SWITCH(value) \
switch ( \
const auto& carbon_internal_kind_switch_value = value; \
::Carbon::Internal::Kind::SwitchOn(carbon_internal_kind_switch_value))
// Produces a case-compatible block of code that also instantiates a local typed
// variable. typed_variable_declaration looks like `int i`, with a space.
//
// This uses `if` to scope the variable, and provides a dangling `else` in order
// to prevent accidental `else` use. The label allows `:` to follow the macro
// name, making it look more like a typical `case`.
//
// NOLINTBEGIN(bugprone-macro-parentheses)
#define CARBON_KIND(typed_variable_declaration) \
::Carbon::Internal::Kind::ForCase< \
decltype([]([[maybe_unused]] typed_variable_declaration) {})>() \
: if (typed_variable_declaration = ::Carbon::Internal::Kind::Cast< \
decltype([]([[maybe_unused]] typed_variable_declaration) {})>( \
carbon_internal_kind_switch_value); \
false) {} \
else [[maybe_unused]] CARBON_INTERNAL_KIND_LABEL(__LINE__)
// NOLINTEND(bugprone-macro-parentheses)
#endif // CARBON_TOOLCHAIN_BASE_KIND_SWITCH_H_
toolchain/sem_ir/BUILD
+1
View File
@@ -127,6 +127,7 @@ cc_library(
":ids",
":inst_kind",
"//common:ostream",
"//toolchain/base:kind_switch",
"//toolchain/base:value_store",
"//toolchain/lex:tokenized_buffer",
"//toolchain/parse:tree",
toolchain/sem_ir/formatter.cpp
+39 -45
View File
@@ -9,6 +9,7 @@
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/SaveAndRestore.h"
#include "toolchain/base/kind_switch.h"
#include "toolchain/base/value_store.h"
#include "toolchain/lex/tokenized_buffer.h"
#include "toolchain/parse/tree.h"
@@ -446,7 +447,7 @@ class InstNamer {
continue;
}
auto inst = sem_ir_.insts().Get(inst_id);
auto untyped_inst = sem_ir_.insts().Get(inst_id);
auto add_inst_name = [&](std::string name) {
insts[inst_id.index] = {
scope_id, scope.insts.AllocateName(
@@ -457,59 +458,55 @@ class InstNamer {
(sem_ir_.names().GetIRBaseName(name_id).str() + suffix).str());
};
if (auto branch = inst.TryAs<AnyBranch>()) {
if (auto branch = untyped_inst.TryAs<AnyBranch>()) {
AddBlockLabel(scope_id, sem_ir_.insts().GetNodeId(inst_id), *branch);
}
switch (inst.kind()) {
case AddrPattern::Kind: {
CARBON_KIND_SWITCH(untyped_inst) {
case CARBON_KIND(AddrPattern inst): {
// TODO: We need to assign names to parameters that appear in
// function declarations, which may be nested within a pattern. For
// now, just look through `addr`, but we should find a better way to
// visit parameters.
CollectNamesInBlock(scope_id, inst.As<AddrPattern>().inner_id);
CollectNamesInBlock(scope_id, inst.inner_id);
break;
}
case AssociatedConstantDecl::Kind: {
add_inst_name_id(inst.As<AssociatedConstantDecl>().name_id);
case CARBON_KIND(AssociatedConstantDecl inst): {
add_inst_name_id(inst.name_id);
continue;
}
case BindAlias::Kind:
case BindName::Kind:
case BindSymbolicName::Kind: {
add_inst_name_id(sem_ir_.bind_names()
.Get(inst.As<AnyBindName>().bind_name_id)
.name_id);
auto inst = untyped_inst.As<AnyBindName>();
add_inst_name_id(sem_ir_.bind_names().Get(inst.bind_name_id).name_id);
continue;
}
case ClassDecl::Kind: {
add_inst_name_id(
sem_ir_.classes().Get(inst.As<ClassDecl>().class_id).name_id,
".decl");
CollectNamesInBlock(scope_id, inst.As<ClassDecl>().decl_block_id);
case CARBON_KIND(ClassDecl inst): {
add_inst_name_id(sem_ir_.classes().Get(inst.class_id).name_id,
".decl");
CollectNamesInBlock(scope_id, inst.decl_block_id);
continue;
}
case ClassType::Kind: {
add_inst_name_id(
sem_ir_.classes().Get(inst.As<ClassType>().class_id).name_id);
case CARBON_KIND(ClassType inst): {
add_inst_name_id(sem_ir_.classes().Get(inst.class_id).name_id);
continue;
}
case FunctionDecl::Kind: {
add_inst_name_id(sem_ir_.functions()
.Get(inst.As<FunctionDecl>().function_id)
.name_id);
CollectNamesInBlock(scope_id, inst.As<FunctionDecl>().decl_block_id);
case CARBON_KIND(FunctionDecl inst): {
add_inst_name_id(sem_ir_.functions().Get(inst.function_id).name_id);
CollectNamesInBlock(scope_id, inst.decl_block_id);
continue;
}
case ImplDecl::Kind: {
CollectNamesInBlock(scope_id, inst.As<ImplDecl>().decl_block_id);
case CARBON_KIND(ImplDecl inst): {
CollectNamesInBlock(scope_id, inst.decl_block_id);
break;
}
case ImportRefUnused::Kind:
case ImportRefUsed::Kind: {
add_inst_name("import_ref");
// When building import refs, we frequently add instructions without a
// block. Constants that refer to them need to be separately named.
// When building import refs, we frequently add instructions without
// a block. Constants that refer to them need to be separately
// named.
auto const_id = sem_ir_.constant_values().Get(inst_id);
if (const_id.is_valid() && const_id.is_template() &&
!insts[const_id.inst_id().index].second) {
@@ -517,35 +514,32 @@ class InstNamer {
}
continue;
}
case InterfaceDecl::Kind: {
add_inst_name_id(sem_ir_.interfaces()
.Get(inst.As<InterfaceDecl>().interface_id)
.name_id,
case CARBON_KIND(InterfaceDecl inst): {
add_inst_name_id(sem_ir_.interfaces().Get(inst.interface_id).name_id,
".decl");
CollectNamesInBlock(scope_id, inst.As<InterfaceDecl>().decl_block_id);
CollectNamesInBlock(scope_id, inst.decl_block_id);
continue;
}
case NameRef::Kind: {
add_inst_name_id(inst.As<NameRef>().name_id, ".ref");
case CARBON_KIND(NameRef inst): {
add_inst_name_id(inst.name_id, ".ref");
continue;
}
// The namespace is specified here due to the name conflict.
case SemIR::Namespace::Kind: {
add_inst_name_id(sem_ir_.name_scopes()
.Get(inst.As<SemIR::Namespace>().name_scope_id)
.name_id);
case CARBON_KIND(SemIR::Namespace inst): {
add_inst_name_id(
sem_ir_.name_scopes().Get(inst.name_scope_id).name_id);
continue;
}
case Param::Kind: {
add_inst_name_id(inst.As<Param>().name_id);
case CARBON_KIND(Param inst): {
add_inst_name_id(inst.name_id);
continue;
}
case SpliceBlock::Kind: {
CollectNamesInBlock(scope_id, inst.As<SpliceBlock>().block_id);
case CARBON_KIND(SpliceBlock inst): {
CollectNamesInBlock(scope_id, inst.block_id);
break;
}
case VarStorage::Kind: {
add_inst_name_id(inst.As<VarStorage>().name_id, ".var");
case CARBON_KIND(VarStorage inst): {
add_inst_name_id(inst.name_id, ".var");
continue;
}
default: {
@@ -554,7 +548,7 @@ class InstNamer {
}
// Sequentially number all remaining values.
if (inst.kind().value_kind() != InstValueKind::None) {
if (untyped_inst.kind().value_kind() != InstValueKind::None) {
add_inst_name("");
}
}