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// The only file that talks to clang. Keep it that way: clang::CodeGen clashes
// with cps::CodeGen, clang is built without RTTI (so never subclass its
// classes here), and the CodeGenerator must be destroyed before the ASTContext.
#include "cps/CABI.h"
#include "cps/TypeSystem.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/DiagnosticOptions.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/CodeGen/CGFunctionInfo.h"
#include "clang/CodeGen/CodeGenABITypes.h"
#include "clang/CodeGen/ModuleBuilder.h"
#include "clang/Driver/CreateInvocationFromArgs.h"
#include "clang/Frontend/CompilerInvocation.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/VirtualFileSystem.h"
#include "llvm/TargetParser/Host.h"
#include <map>
using namespace cps;
using clang::CodeGen::ABIArgInfo;
// Members are destroyed in reverse order, so Gen goes before AST.
struct ClangABI::State {
const TypeSystem *Types = nullptr;
clang::DiagnosticOptions DiagOpts;
llvm::IntrusiveRefCntPtr<clang::DiagnosticsEngine> Diags;
std::shared_ptr<clang::CompilerInvocation> Invocation;
llvm::IntrusiveRefCntPtr<clang::FileManager> Files;
std::unique_ptr<clang::SourceManager> Sources;
llvm::IntrusiveRefCntPtr<clang::TargetInfo> Target;
std::unique_ptr<clang::IdentifierTable> Idents;
clang::SelectorTable Selectors;
clang::Builtin::Context Builtins;
std::unique_ptr<clang::ASTContext> AST;
std::unique_ptr<clang::CodeGenerator> Gen;
std::map<const TypeInfo *, clang::CanQualType> Records;
// Target and language options come from a driver invocation for the host
// triple, as the C compiler would use them (e.g. Apple's darwinpcs and the
// signedness of char).
bool init(llvm::LLVMContext &Context, std::string &Err) {
Diags = llvm::makeIntrusiveRefCnt<clang::DiagnosticsEngine>(
clang::DiagnosticIDs::create(), DiagOpts, new clang::IgnoringDiagConsumer());
std::string Triple = llvm::sys::getProcessTriple();
std::string TargetArg = "--target=" + Triple;
const char *Args[] = {"clang", TargetArg.c_str(), "-fsyntax-only", "-x", "c", "cps-abi.c"};
clang::CreateInvocationOptions Opts;
Opts.Diags = Diags;
Invocation = clang::createInvocation(Args, Opts);
if (Invocation) Target = clang::TargetInfo::CreateTargetInfo(*Diags, Invocation->getTargetOpts());
if (!Target) {
Err = "cannot create a clang C ABI context for " + Triple;
return false;
}
clang::LangOptions &Lang = Invocation->getLangOpts();
Target->adjust(*Diags, Lang, nullptr);
auto VFS = llvm::vfs::getRealFileSystem();
Files = llvm::makeIntrusiveRefCnt<clang::FileManager>(clang::FileSystemOptions(), VFS);
Sources = std::make_unique<clang::SourceManager>(*Diags, *Files);
Idents = std::make_unique<clang::IdentifierTable>(Lang);
AST = std::make_unique<clang::ASTContext>(Lang, *Sources, *Idents, Selectors, Builtins,
clang::TU_Complete);
AST->InitBuiltinTypes(*Target);
Gen = clang::CreateLLVMCodeGen(*Diags, "cps-abi", VFS, Invocation->getHeaderSearchOpts(),
Invocation->getPreprocessorOpts(),
Invocation->getCodeGenOpts(), Context);
Gen->Initialize(*AST);
return true;
}
// C scalars map by name and every pointer to void *; records are built
// once and checked against cpsc's layout.
bool map(const TypeInfo *Info, clang::CanQualType &Out, std::string &Err) {
using Member = clang::CanQualType clang::ASTContext::*;
static const std::map<std::string, Member> Scalars = {
{"_Bool", &clang::ASTContext::BoolTy},
{"char", &clang::ASTContext::CharTy},
{"signed char", &clang::ASTContext::SignedCharTy},
{"unsigned char", &clang::ASTContext::UnsignedCharTy},
{"short", &clang::ASTContext::ShortTy},
{"unsigned short", &clang::ASTContext::UnsignedShortTy},
{"int", &clang::ASTContext::IntTy},
{"unsigned int", &clang::ASTContext::UnsignedIntTy},
{"long", &clang::ASTContext::LongTy},
{"unsigned long", &clang::ASTContext::UnsignedLongTy},
{"long long", &clang::ASTContext::LongLongTy},
{"unsigned long long", &clang::ASTContext::UnsignedLongLongTy},
{"float", &clang::ASTContext::FloatTy},
{"double", &clang::ASTContext::DoubleTy},
{"long double", &clang::ASTContext::LongDoubleTy},
};
if (Info && (Info->Kind == TypeKind::CPointer || Info->Kind == TypeKind::Pointer)) {
Out = AST->VoidPtrTy;
return true;
}
if (Info && Info->Kind == TypeKind::CScalar) {
auto It = Scalars.find(Info->CIdentity);
if (It != Scalars.end()) {
Out = (*AST).*(It->second);
return true;
}
}
if (!Info || !Info->isRecord()) {
Err = "no C type for " + (Info ? Info->Name : std::string("an unknown type"));
return false;
}
auto Cached = Records.find(Info);
if (Cached != Records.end()) {
Out = Cached->second;
return true;
}
clang::TranslationUnitDecl *Unit = AST->getTranslationUnitDecl();
auto *Record = clang::RecordDecl::Create(*AST, clang::TagTypeKind::Struct, Unit, {}, {},
&AST->Idents.get(Info->Name));
Record->startDefinition();
for (const auto &[Name, Field] : Info->Record.Fields) {
clang::CanQualType FieldType;
if (!map(Types->resolve(Field.TypeName), FieldType, Err)) return false;
auto *Decl = clang::FieldDecl::Create(*AST, Record, {}, {}, &AST->Idents.get(Name),
FieldType, nullptr, nullptr, false,
clang::ICIS_NoInit);
Decl->setAccess(clang::AS_public);
Record->addDecl(Decl);
}
Record->completeDefinition();
Unit->addDecl(Record);
Out = AST->getCanonicalTagType(Record);
uint64_t CSize = AST->getTypeSizeInChars(Out).getQuantity();
uint64_t Size = Gen->GetModule()->getDataLayout().getTypeAllocSize(Info->LLVMType);
if (CSize != Size) {
Err = "record " + Info->Name + " has " + std::to_string(Size) + " bytes in cpsc but " +
std::to_string(CSize) + " in C";
return false;
}
Records.emplace(Info, Out);
return true;
}
};
namespace {
bool translate(const ABIArgInfo &I, llvm::Type *ValueType, const std::string &What, CABIArg &Out,
std::string &Err) {
Out.ValueType = ValueType;
const char *Unsupported = nullptr;
switch (I.getKind()) {
case ABIArgInfo::Direct:
case ABIArgInfo::Extend:
Out.K = I.isDirect() ? CABIArg::Kind::Direct : CABIArg::Kind::Extend;
Out.CoerceType = I.getCoerceToType();
Out.Offset = I.getDirectOffset();
Out.DirectAlign = I.getDirectAlign();
Out.Flatten = I.isDirect() && I.getCanBeFlattened() && llvm::isa<llvm::StructType>(Out.CoerceType);
if (I.isExtend())
Out.Extension = I.isSignExt() ? llvm::Attribute::SExt
: I.isZeroExt() ? llvm::Attribute::ZExt : llvm::Attribute::NoExt;
Out.InReg = I.getInReg();
break;
case ABIArgInfo::Indirect:
Out.K = CABIArg::Kind::Indirect;
Out.ByVal = I.getIndirectByVal();
Out.Align = I.getIndirectAlign().getQuantity();
Out.InReg = I.getInReg();
break;
case ABIArgInfo::Ignore:
Out.K = CABIArg::Kind::Ignore;
break;
case ABIArgInfo::IndirectAliased: Unsupported = "IndirectAliased"; break;
case ABIArgInfo::Expand: Unsupported = "Expand"; break;
case ABIArgInfo::CoerceAndExpand: Unsupported = "CoerceAndExpand"; break;
case ABIArgInfo::InAlloca: Unsupported = "InAlloca"; break;
case ABIArgInfo::TargetSpecific: Unsupported = "TargetSpecific"; break;
}
if (!Unsupported && I.getPaddingType()) Unsupported = "with a padding type";
if (Unsupported) {
Err = "unsupported C ABI kind " + std::string(Unsupported) + " for " + What;
return false;
}
return true;
}
} // namespace
ClangABI::ClangABI(llvm::LLVMContext &Context, const TypeSystem &Types)
: Context(Context), Types(Types) {}
ClangABI::~ClangABI() = default;
bool ClangABI::arrange(const TypeInfo *Ret, const std::vector<const TypeInfo *> &Args, size_t Fixed,
bool Variadic, CABISignature &Sig, std::string &Err) {
if (!S) {
auto Fresh = std::make_unique<State>();
Fresh->Types = &Types;
if (!Fresh->init(Context, Err)) return false;
S = std::move(Fresh);
}
clang::CanQualType RetType = S->AST->VoidTy;
if (Ret && !S->map(Ret, RetType, Err)) return false;
std::vector<clang::CanQualType> ArgTypes(Args.size());
for (size_t I = 0; I < Args.size(); ++I)
if (!S->map(Args[I], ArgTypes[I], Err)) return false;
clang::CodeGen::RequiredArgs Required = Variadic
? clang::CodeGen::RequiredArgs(Fixed) : clang::CodeGen::RequiredArgs::All;
const clang::CodeGen::CGFunctionInfo &Info = clang::CodeGen::arrangeFreeFunctionCall(
S->Gen->CGM(), RetType, ArgTypes, clang::FunctionType::ExtInfo(), Required);
Sig = CABISignature();
Sig.Fixed = Fixed;
Sig.Variadic = Variadic;
Sig.CallingConv = Info.getEffectiveCallingConvention();
if (!translate(Info.getReturnInfo(), Ret ? Ret->LLVMType : llvm::Type::getVoidTy(Context),
"the result", Sig.Ret, Err))
return false;
Sig.Args.resize(Args.size());
for (size_t I = 0; I < Args.size(); ++I)
if (!translate(Info.arguments()[I].info, Args[I]->LLVMType,
(I < Fixed ? "parameter " : "variadic argument ") + std::to_string(I + 1),
Sig.Args[I], Err))
return false;
return true;
}
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