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[Carbon/C++ interop] Add support for int function params (#5197)

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Added support for `int` function parameters. Currently only
pass-by-value is supported.

```c++
// hello_int.h;

auto foo_int(int a, int b) -> int;
```

```c++
// hello_int.cpp

#include "hello_int.h"
#include <cstdio>

auto foo_int(int a, int b) -> int {
    printf("a = %i \n", a);
    printf("b = %i \n", b);
    return a + b;
}
```
```c++
// main.carbon

library "Main";

import Cpp library "hello_int.h";
import Core library "io";

fn Carbon_foo(b: i32) {
  Core.Print(b);
}

fn Run() -> i32 {
  Carbon_foo(Cpp.foo_int(2, 8));
  return 0;
}
```

```
$ clang -c hello_int.cpp
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link hello_int.o main.o --output=demo
$ ./demo
a = 2 
b = 8 
10
```

Part of  #5064
This commit is contained in:
Ivana Ivanovska
2025-04-09 11:38:39 +00:00
committed by GitHub
parent 1a4d6ca255
commit 7580df8b8a
3 changed files with 985 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files
toolchain/check/import_cpp.cpp
+90 -37
View File
@@ -16,6 +16,7 @@
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/raw_ostream.h"
#include "toolchain/check/context.h"
#include "toolchain/check/convert.h"
#include "toolchain/check/diagnostic_helpers.h"
#include "toolchain/check/import.h"
#include "toolchain/check/inst.h"
@@ -26,6 +27,7 @@
#include "toolchain/parse/node_ids.h"
#include "toolchain/sem_ir/ids.h"
#include "toolchain/sem_ir/name_scope.h"
#include "toolchain/sem_ir/typed_insts.h"
namespace Carbon::Check {
@@ -254,6 +256,74 @@ static auto ClangLookup(Context& context, SemIR::LocId loc_id,
return lookup;
}
// Creates an integer type of the given size.
static auto MakeIntType(Context& context, IntId size_id) -> TypeExpr {
// TODO: Fill in a location for the type once available.
auto type_inst_id = MakeIntTypeLiteral(context, Parse::NodeId::None,
SemIR::IntKind::Signed, size_id);
return ExprAsType(context, Parse::NodeId::None, type_inst_id);
}
// Maps a C++ type to a Carbon type. Currently only 32-bit `int` is supported.
// TODO: Support more types.
static auto MapType(Context& context, clang::QualType type) -> TypeExpr {
const auto* builtin_type = dyn_cast<clang::BuiltinType>(type);
if (builtin_type && builtin_type->getKind() == clang::BuiltinType::Int &&
context.ast_context().getTypeSize(type) == 32) {
return MakeIntType(context, context.ints().Add(32));
}
return {.inst_id = SemIR::ErrorInst::SingletonInstId,
.type_id = SemIR::ErrorInst::SingletonTypeId};
}
// Returns a block id for the explicit parameters of the given function
// declaration. If the function declaration has no parameters, it returns
// `SemIR::InstBlockId::Empty`. In the case of an unsupported parameter type, it
// returns `SemIR::InstBlockId::None`.
static auto MakeParamPatternsBlockId(Context& context, SemIR::LocId loc_id,
const clang::FunctionDecl& clang_decl)
-> SemIR::InstBlockId {
if (clang_decl.parameters().empty()) {
return SemIR::InstBlockId::Empty;
}
SemIR::CallParamIndex next_index(0);
llvm::SmallVector<SemIR::InstId> params;
params.reserve(clang_decl.parameters().size());
for (const clang::ParmVarDecl* param : clang_decl.parameters()) {
clang::QualType param_type = param->getType().getCanonicalType();
SemIR::TypeId type_id = MapType(context, param_type).type_id;
if (type_id == SemIR::ErrorInst::SingletonTypeId) {
context.TODO(loc_id, llvm::formatv("Unsupported: parameter type: {0}",
param_type.getAsString()));
return SemIR::InstBlockId::None;
}
llvm::StringRef param_name = param->getName();
SemIR::EntityNameId entity_name_id = context.entity_names().Add(
{.name_id =
(param_name.empty())
// Translate an unnamed parameter to an underscore to
// match Carbon's naming of unnamed/unused function params.
? SemIR::NameId::Underscore
: SemIR::NameId::ForIdentifier(
context.sem_ir().identifiers().Add(param_name)),
.parent_scope_id = SemIR::NameScopeId::None});
SemIR::InstId binding_pattern_id = AddInstInNoBlock(
// TODO: Fill in a location once available.
context, SemIR::LocIdAndInst::NoLoc(SemIR::BindingPattern(
{.type_id = type_id, .entity_name_id = entity_name_id})));
SemIR::InstId var_pattern_id = AddInstInNoBlock(
context,
// TODO: Fill in a location once available.
SemIR::LocIdAndInst::NoLoc(SemIR::ValueParamPattern(
{.type_id = context.insts().Get(binding_pattern_id).type_id(),
.subpattern_id = binding_pattern_id,
.index = next_index})));
++next_index.index;
params.push_back(var_pattern_id);
}
return context.inst_blocks().Add(params);
}
// Returns the return type of the given function declaration.
// Currently only void and 32-bit int are supported.
// TODO: Support more return types.
@@ -264,40 +334,23 @@ static auto GetReturnType(Context& context, SemIRLoc loc_id,
if (ret_type->isVoidType()) {
return SemIR::InstId::None;
}
if (const auto* builtin_type = dyn_cast<clang::BuiltinType>(ret_type);
builtin_type && builtin_type->getKind() == clang::BuiltinType::Int) {
constexpr int SupportedIntWidth = 32;
uint64_t int_size = context.ast_context().getTypeSize(ret_type);
if (int_size != SupportedIntWidth) {
// TODO: Add tests for this case.
context.TODO(loc_id,
llvm::formatv("Unsupported: return type: {0}, size: {1}",
ret_type.getAsString(), int_size));
return SemIR::ErrorInst::SingletonInstId;
}
IntId size_id = context.ints().Add(int_size);
// TODO: Fill in a location for the type once available.
SemIR::TypeId type_id = MakeIntType(context, Parse::NodeId::None,
SemIR::IntKind::Signed, size_id);
// TODO: Fill in a location for the type once available.
SemIR::InstId type_inst_id = MakeIntTypeLiteral(
context, Parse::NodeId::None, SemIR::IntKind::Signed, size_id);
SemIR::InstId return_slot_pattern_id = AddInstInNoBlock(
// TODO: Fill in a location for the return type once available.
context, SemIR::LocIdAndInst::NoLoc(SemIR::ReturnSlotPattern(
{.type_id = type_id, .type_inst_id = type_inst_id})));
SemIR::InstId param_pattern_id = AddInstInNoBlock(
// TODO: Fill in a location for the return type once available.
context, SemIR::LocIdAndInst::NoLoc(SemIR::OutParamPattern(
{.type_id = type_id,
.subpattern_id = return_slot_pattern_id,
.index = SemIR::CallParamIndex::None})));
return param_pattern_id;
auto [type_inst_id, type_id] = MapType(context, ret_type);
if (type_id == SemIR::ErrorInst::SingletonTypeId) {
context.TODO(loc_id, llvm::formatv("Unsupported: return type: {0}",
ret_type.getAsString()));
return SemIR::ErrorInst::SingletonInstId;
}
context.TODO(loc_id, llvm::formatv("Unsupported: return type: {0}",
ret_type.getAsString()));
return SemIR::ErrorInst::SingletonInstId;
SemIR::InstId return_slot_pattern_id = AddInstInNoBlock(
// TODO: Fill in a location for the return type once available.
context, SemIR::LocIdAndInst::NoLoc(SemIR::ReturnSlotPattern(
{.type_id = type_id, .type_inst_id = type_inst_id})));
SemIR::InstId param_pattern_id = AddInstInNoBlock(
// TODO: Fill in a location for the return type once available.
context, SemIR::LocIdAndInst::NoLoc(SemIR::OutParamPattern(
{.type_id = type_id,
.subpattern_id = return_slot_pattern_id,
.index = SemIR::CallParamIndex::None})));
return param_pattern_id;
}
// Imports a function declaration from Clang to Carbon. If successful, returns
@@ -319,11 +372,11 @@ static auto ImportFunctionDecl(Context& context, SemIR::LocId loc_id,
context.TODO(loc_id, "Unsupported: Template function");
return SemIR::ErrorInst::SingletonInstId;
}
if (!clang_decl->param_empty()) {
context.TODO(loc_id, "Unsupported: Function with parameters");
auto param_patterns_id =
MakeParamPatternsBlockId(context, loc_id, *clang_decl);
if (!param_patterns_id.has_value()) {
return SemIR::ErrorInst::SingletonInstId;
}
auto return_slot_pattern_id = GetReturnType(context, loc_id, clang_decl);
if (SemIR::ErrorInst::SingletonInstId == return_slot_pattern_id) {
return SemIR::ErrorInst::SingletonInstId;
@@ -342,7 +395,7 @@ static auto ImportFunctionDecl(Context& context, SemIR::LocId loc_id,
.last_param_node_id = Parse::NodeId::None,
.pattern_block_id = SemIR::InstBlockId::Empty,
.implicit_param_patterns_id = SemIR::InstBlockId::Empty,
.param_patterns_id = SemIR::InstBlockId::Empty,
.param_patterns_id = param_patterns_id,
.is_extern = false,
.extern_library_id = SemIR::LibraryNameId::None,
.non_owning_decl_id = SemIR::InstId::None,