mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 22:02:23 +01:00
Richard SmithandJon Ross-Perkins
1e7b7e53ae
The general strategy here is to force use of a thunk when we want to use default arguments, and have Clang generate uses of the default arguments on its side of the thunk. To support this, change the key type used in `clang_decls` from being just a `Decl*` to being a pair of `Decl*` and number of parameters in the case of function decls. Import distinct `SemIR::Function`s for each number of parameters that's used, and corresponding distinct thunks. --------- Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
251 lines
9.2 KiB
C++
251 lines
9.2 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include "toolchain/lower/mangler.h"
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#include <string>
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#include "common/raw_string_ostream.h"
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#include "toolchain/base/kind_switch.h"
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#include "toolchain/lower/clang_global_decl.h"
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#include "toolchain/sem_ir/entry_point.h"
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#include "toolchain/sem_ir/ids.h"
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#include "toolchain/sem_ir/pattern.h"
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namespace Carbon::Lower {
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auto Mangler::MangleNameId(llvm::raw_ostream& os, SemIR::NameId name_id)
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-> void {
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CARBON_CHECK(name_id.AsIdentifierId().has_value(),
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"Mangling non-identifier name {0}", name_id);
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os << names().GetAsStringIfIdentifier(name_id);
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}
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auto Mangler::MangleInverseQualifiedNameScope(llvm::raw_ostream& os,
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SemIR::NameScopeId name_scope_id)
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-> void {
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// Maintain a stack of names for delayed rendering of interface impls.
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struct NameEntry {
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SemIR::NameScopeId name_scope_id;
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// The prefix emitted before this name component. If '\0', no prefix will be
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// emitted.
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// - Namespace components are separated by '.'.
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// - The two components of an interface are separated by ':'.
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char prefix;
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};
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llvm::SmallVector<NameEntry> names_to_render;
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names_to_render.push_back({.name_scope_id = name_scope_id, .prefix = '.'});
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while (!names_to_render.empty()) {
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auto [name_scope_id, prefix] = names_to_render.pop_back_val();
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if (prefix) {
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os << prefix;
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}
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if (name_scope_id == SemIR::NameScopeId::Package) {
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auto package_id = sem_ir().package_id();
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if (auto ident_id = package_id.AsIdentifierId(); ident_id.has_value()) {
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os << sem_ir().identifiers().Get(ident_id);
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} else {
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// TODO: Handle name conflicts between special package names and raw
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// identifier package names. Note that any change here will also require
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// a change to namespace mangling for imported packages.
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os << package_id.AsSpecialName();
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}
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continue;
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}
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const auto& name_scope = sem_ir().name_scopes().Get(name_scope_id);
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CARBON_KIND_SWITCH(sem_ir().insts().Get(name_scope.inst_id())) {
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case CARBON_KIND(SemIR::ImplDecl impl_decl): {
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const auto& impl = sem_ir().impls().Get(impl_decl.impl_id);
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auto facet_type = insts().GetAs<SemIR::FacetType>(
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constant_values().GetConstantInstId(impl.constraint_id));
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const auto& facet_type_info =
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sem_ir().facet_types().Get(facet_type.facet_type_id);
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CARBON_CHECK(facet_type_info.extend_constraints.size() == 1,
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"Mangling of an impl of something other than a single "
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"interface is not yet supported.");
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auto interface_type = facet_type_info.extend_constraints.front();
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const auto& interface =
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sem_ir().interfaces().Get(interface_type.interface_id);
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names_to_render.push_back(
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{.name_scope_id = interface.scope_id, .prefix = ':'});
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auto self_const_inst_id =
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constant_values().GetConstantInstId(impl.self_id);
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auto self_inst = insts().Get(self_const_inst_id);
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CARBON_KIND_SWITCH(self_inst) {
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case CARBON_KIND(SemIR::ClassType class_type): {
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auto next_name_scope_id =
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sem_ir().classes().Get(class_type.class_id).scope_id;
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names_to_render.push_back(
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{.name_scope_id = next_name_scope_id, .prefix = '\0'});
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break;
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}
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case SemIR::AutoType::Kind:
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case SemIR::BoolType::Kind:
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case SemIR::BoundMethodType::Kind:
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case SemIR::FloatLiteralType::Kind:
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case SemIR::IntLiteralType::Kind:
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case SemIR::NamespaceType::Kind:
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case SemIR::SpecificFunctionType::Kind:
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case SemIR::TypeType::Kind:
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case SemIR::VtableType::Kind:
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case SemIR::WitnessType::Kind: {
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os << self_inst.kind().ir_name();
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break;
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}
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case CARBON_KIND(SemIR::IntType int_type): {
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os << (int_type.int_kind == SemIR::IntKind::Signed ? "i" : "u")
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<< sem_ir().ints().Get(
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sem_ir()
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.insts()
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.GetAs<SemIR::IntValue>(int_type.bit_width_id)
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.int_id);
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break;
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}
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default: {
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// Fall back to including a fingerprint.
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llvm::write_hex(
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os, fingerprinter_.GetOrCompute(&sem_ir(), self_const_inst_id),
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llvm::HexPrintStyle::Lower, 16);
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break;
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}
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}
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// Skip the tail of the loop that adds the parent name scope to the
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// stack - the scope in which the impl was defined is not part of the
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// mangling, the constraint and interface alone uniquelify identify an
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// impl.
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continue;
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}
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case CARBON_KIND(SemIR::ClassDecl class_decl): {
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MangleNameId(os, sem_ir().classes().Get(class_decl.class_id).name_id);
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break;
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}
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case CARBON_KIND(SemIR::InterfaceDecl interface_decl): {
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MangleNameId(
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os, sem_ir().interfaces().Get(interface_decl.interface_id).name_id);
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break;
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}
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case SemIR::Namespace::Kind: {
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os << names().GetIRBaseName(name_scope.name_id());
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break;
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}
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default:
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CARBON_FATAL("Attempting to mangle unsupported SemIR.");
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break;
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}
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if (!name_scope.is_imported_package()) {
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names_to_render.push_back(
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{.name_scope_id = name_scope.parent_scope_id(), .prefix = '.'});
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}
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}
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}
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auto Mangler::Mangle(SemIR::FunctionId function_id,
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SemIR::SpecificId specific_id) -> std::string {
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const auto& function = sem_ir().functions().Get(function_id);
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if (SemIR::IsEntryPoint(sem_ir(), function_id)) {
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CARBON_CHECK(!specific_id.has_value(), "entry point should not be generic");
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return "main";
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}
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if (function.clang_decl_id.has_value()) {
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CARBON_CHECK(function.special_function_kind !=
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SemIR::Function::SpecialFunctionKind::HasCppThunk,
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"Shouldn't mangle C++ function that uses a thunk");
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const auto& clang_decl = sem_ir().clang_decls().Get(function.clang_decl_id);
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return MangleCppClang(cast<clang::NamedDecl>(clang_decl.key.decl));
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}
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RawStringOstream os;
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os << "_C";
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MangleNameId(os, function.name_id);
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// For a special function, add a marker to disambiguate.
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switch (function.special_function_kind) {
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case SemIR::Function::SpecialFunctionKind::None:
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break;
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case SemIR::Function::SpecialFunctionKind::Builtin:
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CARBON_FATAL("Attempting to mangle declaration of builtin function {0}",
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function.builtin_function_kind());
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case SemIR::Function::SpecialFunctionKind::Thunk:
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os << ":thunk";
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break;
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case SemIR::Function::SpecialFunctionKind::HasCppThunk:
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CARBON_FATAL("C++ functions should have been handled earlier");
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}
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// TODO: If the function is private, also include the library name as part of
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// the mangling.
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MangleInverseQualifiedNameScope(os, function.parent_scope_id);
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MangleSpecificId(os, specific_id);
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return os.TakeStr();
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}
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auto Mangler::MangleSpecificId(llvm::raw_ostream& os,
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SemIR::SpecificId specific_id) -> void {
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// TODO: Add proper support for mangling generic entities. For now we use a
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// fingerprint of the specific arguments, which should be stable across files,
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// but isn't necessarily stable across toolchain changes.
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if (specific_id.has_value()) {
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os << ".";
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llvm::write_hex(
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os,
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fingerprinter_.GetOrCompute(
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&sem_ir(), sem_ir().specifics().Get(specific_id).args_id),
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llvm::HexPrintStyle::Lower, 16);
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}
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}
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auto Mangler::MangleGlobalVariable(SemIR::InstId pattern_id) -> std::string {
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// Use the name of the first binding in the variable as its mangled name.
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auto var_name_id =
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SemIR::GetFirstBindingNameFromPatternId(sem_ir(), pattern_id);
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if (!var_name_id.has_value()) {
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return std::string();
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}
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auto var_name = sem_ir().entity_names().Get(var_name_id);
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if (var_name.clang_decl_id.has_value()) {
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return MangleCppClang(cast<clang::NamedDecl>(
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sem_ir().clang_decls().Get(var_name.clang_decl_id).key.decl));
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}
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RawStringOstream os;
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os << "_C";
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MangleNameId(os, var_name.name_id);
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// TODO: If the variable is private, also include the library name as part of
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// the mangling.
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MangleInverseQualifiedNameScope(os, var_name.parent_scope_id);
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return os.TakeStr();
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}
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auto Mangler::MangleCppClang(const clang::NamedDecl* decl) -> std::string {
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return file_context_.cpp_code_generator()
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.GetMangledName(CreateGlobalDecl(decl))
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.str();
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}
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auto Mangler::MangleVTable(const SemIR::Class& class_info,
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SemIR::SpecificId specific_id) -> std::string {
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RawStringOstream os;
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os << "_C";
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MangleNameId(os, class_info.name_id);
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// TODO: If the class is private, also include the library name as part of the
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// mangling.
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MangleInverseQualifiedNameScope(os, class_info.parent_scope_id);
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os << ".$vtable";
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MangleSpecificId(os, specific_id);
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return os.TakeStr();
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}
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} // namespace Carbon::Lower
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