Files
carbon-lang/toolchain/lower/mangler.cpp
T
Richard Smith 4e5dccdbf7 When making a direct call to a thunk, inline the call in SemIR. (#5642)
This preserves the constant values of the arguments to the thunk, which
is important if the thunk requires conversion of an `IntLiteral` to some
other type. This should become unnecessary once we have form support,
but avoiding the indirection through a thunk function seems valuable
even once that support is in place.

To support this, track whether a function is a thunk on the Function
object, and if so, what the callee of the thunk is. This information is
also included in formatted SemIR when dumping the thunk.
2025-06-11 21:34:01 +00:00

238 lines
8.6 KiB
C++

// 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/lower/mangler.h"
#include <string>
#include "common/raw_string_ostream.h"
#include "toolchain/base/kind_switch.h"
#include "toolchain/sem_ir/entry_point.h"
#include "toolchain/sem_ir/ids.h"
#include "toolchain/sem_ir/pattern.h"
namespace Carbon::Lower {
auto Mangler::MangleNameId(llvm::raw_ostream& os, SemIR::NameId name_id)
-> void {
CARBON_CHECK(name_id.AsIdentifierId().has_value(),
"Mangling non-identifier name {0}", name_id);
os << names().GetAsStringIfIdentifier(name_id);
}
auto Mangler::MangleInverseQualifiedNameScope(llvm::raw_ostream& os,
SemIR::NameScopeId name_scope_id)
-> void {
// Maintain a stack of names for delayed rendering of interface impls.
struct NameEntry {
SemIR::NameScopeId name_scope_id;
// The prefix emitted before this name component. If '\0', no prefix will be
// emitted.
// - Namespace components are separated by '.'.
// - The two components of an interface are separated by ':'.
char prefix;
};
llvm::SmallVector<NameEntry> names_to_render;
names_to_render.push_back({.name_scope_id = name_scope_id, .prefix = '.'});
while (!names_to_render.empty()) {
auto [name_scope_id, prefix] = names_to_render.pop_back_val();
if (prefix) {
os << prefix;
}
if (name_scope_id == SemIR::NameScopeId::Package) {
auto package_id = sem_ir().package_id();
if (auto ident_id = package_id.AsIdentifierId(); ident_id.has_value()) {
os << sem_ir().identifiers().Get(ident_id);
} else {
// TODO: Handle name conflicts between special package names and raw
// identifier package names. Note that any change here will also require
// a change to namespace mangling for imported packages.
os << package_id.AsSpecialName();
}
continue;
}
const auto& name_scope = sem_ir().name_scopes().Get(name_scope_id);
CARBON_KIND_SWITCH(sem_ir().insts().Get(name_scope.inst_id())) {
case CARBON_KIND(SemIR::ImplDecl impl_decl): {
const auto& impl = sem_ir().impls().Get(impl_decl.impl_id);
auto facet_type = insts().GetAs<SemIR::FacetType>(
constant_values().GetConstantInstId(impl.constraint_id));
const auto& facet_type_info =
sem_ir().facet_types().Get(facet_type.facet_type_id);
CARBON_CHECK(facet_type_info.extend_constraints.size() == 1,
"Mangling of an impl of something other than a single "
"interface is not yet supported.");
auto interface_type = facet_type_info.extend_constraints.front();
const auto& interface =
sem_ir().interfaces().Get(interface_type.interface_id);
names_to_render.push_back(
{.name_scope_id = interface.scope_id, .prefix = ':'});
auto self_const_inst_id =
constant_values().GetConstantInstId(impl.self_id);
auto self_inst = insts().Get(self_const_inst_id);
CARBON_KIND_SWITCH(self_inst) {
case CARBON_KIND(SemIR::ClassType class_type): {
auto next_name_scope_id =
sem_ir().classes().Get(class_type.class_id).scope_id;
names_to_render.push_back(
{.name_scope_id = next_name_scope_id, .prefix = '\0'});
break;
}
case SemIR::AutoType::Kind:
case SemIR::BoolType::Kind:
case SemIR::BoundMethodType::Kind:
case SemIR::IntLiteralType::Kind:
case SemIR::LegacyFloatType::Kind:
case SemIR::NamespaceType::Kind:
case SemIR::SpecificFunctionType::Kind:
case SemIR::StringType::Kind:
case SemIR::TypeType::Kind:
case SemIR::VtableType::Kind:
case SemIR::WitnessType::Kind: {
os << self_inst.kind().ir_name();
break;
}
case CARBON_KIND(SemIR::IntType int_type): {
os << (int_type.int_kind == SemIR::IntKind::Signed ? "i" : "u")
<< sem_ir().ints().Get(
sem_ir()
.insts()
.GetAs<SemIR::IntValue>(int_type.bit_width_id)
.int_id);
break;
}
default: {
// Fall back to including a fingerprint.
llvm::write_hex(
os, fingerprinter_.GetOrCompute(&sem_ir(), self_const_inst_id),
llvm::HexPrintStyle::Lower, 16);
break;
}
}
// Skip the tail of the loop that adds the parent name scope to the
// stack - the scope in which the impl was defined is not part of the
// mangling, the constraint and interface alone uniquelify identify an
// impl.
continue;
}
case CARBON_KIND(SemIR::ClassDecl class_decl): {
MangleNameId(os, sem_ir().classes().Get(class_decl.class_id).name_id);
break;
}
case CARBON_KIND(SemIR::InterfaceDecl interface_decl): {
MangleNameId(
os, sem_ir().interfaces().Get(interface_decl.interface_id).name_id);
break;
}
case SemIR::Namespace::Kind: {
os << names().GetIRBaseName(name_scope.name_id());
break;
}
default:
CARBON_FATAL("Attempting to mangle unsupported SemIR.");
break;
}
if (!name_scope.is_imported_package()) {
names_to_render.push_back(
{.name_scope_id = name_scope.parent_scope_id(), .prefix = '.'});
}
}
}
auto Mangler::Mangle(SemIR::FunctionId function_id,
SemIR::SpecificId specific_id) -> std::string {
const auto& function = sem_ir().functions().Get(function_id);
if (SemIR::IsEntryPoint(sem_ir(), function_id)) {
CARBON_CHECK(!specific_id.has_value(), "entry point should not be generic");
return "main";
}
if (function.clang_decl_id.has_value()) {
return MangleCppClang(llvm::dyn_cast<clang::NamedDecl>(
sem_ir().clang_decls().Get(function.clang_decl_id)));
}
RawStringOstream os;
os << "_C";
MangleNameId(os, function.name_id);
// For a special function, add a marker to disambiguate.
switch (function.special_function_kind) {
case SemIR::Function::SpecialFunctionKind::None:
break;
case SemIR::Function::SpecialFunctionKind::Builtin:
CARBON_FATAL("Attempting to mangle declaration of builtin function {0}",
function.builtin_function_kind());
case SemIR::Function::SpecialFunctionKind::Thunk:
os << ":thunk";
break;
}
// TODO: If the function is private, also include the library name as part of
// the mangling.
MangleInverseQualifiedNameScope(os, function.parent_scope_id);
// TODO: Add proper support for mangling generic entities. For now we use a
// fingerprint of the specific arguments, which should be stable across files,
// but isn't necessarily stable across toolchain changes.
if (specific_id.has_value()) {
os << ".";
llvm::write_hex(
os,
fingerprinter_.GetOrCompute(
&sem_ir(), sem_ir().specifics().Get(specific_id).args_id),
llvm::HexPrintStyle::Lower, 16);
}
return os.TakeStr();
}
auto Mangler::MangleGlobalVariable(SemIR::InstId pattern_id) -> std::string {
// Use the name of the first binding in the variable as its mangled name.
auto var_name_id =
SemIR::GetFirstBindingNameFromPatternId(sem_ir(), pattern_id);
if (!var_name_id.has_value()) {
return std::string();
}
RawStringOstream os;
os << "_C";
auto var_name = sem_ir().entity_names().Get(var_name_id);
MangleNameId(os, var_name.name_id);
// TODO: If the variable is private, also include the library name as part of
// the mangling.
MangleInverseQualifiedNameScope(os, var_name.parent_scope_id);
return os.TakeStr();
}
auto Mangler::MangleCppClang(const clang::NamedDecl* decl) -> std::string {
CARBON_CHECK(
cpp_mangle_context_,
"Mangling of a C++ imported declaration without a Clang `MangleContext`");
RawStringOstream cpp_mangled_name;
cpp_mangle_context_->mangleName(decl, cpp_mangled_name);
return cpp_mangled_name.TakeStr();
}
auto Mangler::MangleVTable(const SemIR::Class& class_info) -> std::string {
RawStringOstream os;
os << "_C";
MangleNameId(os, class_info.name_id);
// TODO: If the class is private, also include the library name as part of the
// mangling.
MangleInverseQualifiedNameScope(os, class_info.parent_scope_id);
os << ".$vtable";
return os.TakeStr();
}
} // namespace Carbon::Lower