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llvm-project/clang/lib/CodeGen/CodeGenModule.cpp

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//===--- CodeGenModule.cpp - Emit LLVM Code from ASTs for a Module --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This coordinates the per-module state used while generating code.
//
//===----------------------------------------------------------------------===//
#include "CodeGenModule.h"
#include "CodeGenFunction.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/CallingConv.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Intrinsics.h"
#include <algorithm>
using namespace clang;
using namespace CodeGen;
CodeGenModule::CodeGenModule(ASTContext &C, const LangOptions &LO,
llvm::Module &M, const llvm::TargetData &TD,
Diagnostic &diags)
: Context(C), Features(LO), TheModule(M), TheTargetData(TD), Diags(diags),
Types(C, M, TD), MemCpyFn(0), MemSetFn(0), CFConstantStringClassRef(0) {
//TODO: Make this selectable at runtime
Runtime = CreateObjCRuntime(M);
}
CodeGenModule::~CodeGenModule() {
EmitGlobalCtors();
delete Runtime;
}
/// WarnUnsupported - Print out a warning that codegen doesn't support the
/// specified stmt yet.
void CodeGenModule::WarnUnsupported(const Stmt *S, const char *Type) {
unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Warning,
"cannot codegen this %0 yet");
SourceRange Range = S->getSourceRange();
std::string Msg = Type;
getDiags().Report(Context.getFullLoc(S->getLocStart()), DiagID,
&Msg, 1, &Range, 1);
}
/// WarnUnsupported - Print out a warning that codegen doesn't support the
/// specified decl yet.
void CodeGenModule::WarnUnsupported(const Decl *D, const char *Type) {
unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Warning,
"cannot codegen this %0 yet");
std::string Msg = Type;
getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID,
&Msg, 1);
}
/// AddGlobalCtor - Add a function to the list that will be called before
/// main() runs.
void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor) {
// TODO: Type coercion of void()* types.
GlobalCtors.push_back(Ctor);
}
void CodeGenModule::EmitGlobalCtors() {
// Get the type of @llvm.global_ctors
std::vector<const llvm::Type*> CtorFields;
CtorFields.push_back(llvm::IntegerType::get(32));
// Constructor function type
std::vector<const llvm::Type*> VoidArgs;
llvm::FunctionType* CtorFuncTy = llvm::FunctionType::get(
llvm::Type::VoidTy,
VoidArgs,
false);
// i32, function type pair
const llvm::Type *FPType = llvm::PointerType::getUnqual(CtorFuncTy);
llvm::StructType* CtorStructTy =
llvm::StructType::get(llvm::Type::Int32Ty, FPType, NULL);
// Array of fields
llvm::ArrayType* GlobalCtorsTy =
llvm::ArrayType::get(CtorStructTy, GlobalCtors.size());
// Define the global variable
llvm::GlobalVariable *GlobalCtorsVal =
new llvm::GlobalVariable(GlobalCtorsTy, false,
llvm::GlobalValue::AppendingLinkage,
(llvm::Constant*)0, "llvm.global_ctors",
&TheModule);
// Populate the array
std::vector<llvm::Constant*> CtorValues;
llvm::Constant *MagicNumber =
llvm::ConstantInt::get(llvm::Type::Int32Ty, 65535, false);
std::vector<llvm::Constant*> StructValues;
for (std::vector<llvm::Constant*>::iterator I = GlobalCtors.begin(),
E = GlobalCtors.end(); I != E; ++I) {
StructValues.clear();
StructValues.push_back(MagicNumber);
StructValues.push_back(*I);
CtorValues.push_back(llvm::ConstantStruct::get(CtorStructTy, StructValues));
}
GlobalCtorsVal->setInitializer(llvm::ConstantArray::get(GlobalCtorsTy,
CtorValues));
}
/// ReplaceMapValuesWith - This is a really slow and bad function that
/// searches for any entries in GlobalDeclMap that point to OldVal, changing
/// them to point to NewVal. This is badbadbad, FIXME!
void CodeGenModule::ReplaceMapValuesWith(llvm::Constant *OldVal,
llvm::Constant *NewVal) {
for (llvm::DenseMap<const Decl*, llvm::Constant*>::iterator
I = GlobalDeclMap.begin(), E = GlobalDeclMap.end(); I != E; ++I)
if (I->second == OldVal) I->second = NewVal;
}
llvm::Constant *CodeGenModule::GetAddrOfFunctionDecl(const FunctionDecl *D,
bool isDefinition) {
// See if it is already in the map. If so, just return it.
llvm::Constant *&Entry = GlobalDeclMap[D];
if (Entry) return Entry;
const llvm::Type *Ty = getTypes().ConvertType(D->getType());
// Check to see if the function already exists.
llvm::Function *F = getModule().getFunction(D->getName());
const llvm::FunctionType *FTy = cast<llvm::FunctionType>(Ty);
// If it doesn't already exist, just create and return an entry.
if (F == 0) {
// FIXME: param attributes for sext/zext etc.
F = new llvm::Function(FTy, llvm::Function::ExternalLinkage, D->getName(),
&getModule());
// Set the appropriate calling convention for the Function.
if (D->getAttr<FastCallAttr>())
F->setCallingConv(llvm::CallingConv::Fast);
return Entry = F;
}
// If the pointer type matches, just return it.
llvm::Type *PFTy = llvm::PointerType::getUnqual(Ty);
if (PFTy == F->getType()) return Entry = F;
// If this isn't a definition, just return it casted to the right type.
if (!isDefinition)
return Entry = llvm::ConstantExpr::getBitCast(F, PFTy);
// Otherwise, we have a definition after a prototype with the wrong type.
// F is the Function* for the one with the wrong type, we must make a new
// Function* and update everything that used F (a declaration) with the new
// Function* (which will be a definition).
//
// This happens if there is a prototype for a function (e.g. "int f()") and
// then a definition of a different type (e.g. "int f(int x)"). Start by
// making a new function of the correct type, RAUW, then steal the name.
llvm::Function *NewFn = new llvm::Function(FTy,
llvm::Function::ExternalLinkage,
"", &getModule());
NewFn->takeName(F);
// Replace uses of F with the Function we will endow with a body.
llvm::Constant *NewPtrForOldDecl =
llvm::ConstantExpr::getBitCast(NewFn, F->getType());
F->replaceAllUsesWith(NewPtrForOldDecl);
// FIXME: Update the globaldeclmap for the previous decl of this name. We
// really want a way to walk all of these, but we don't have it yet. This
// is incredibly slow!
ReplaceMapValuesWith(F, NewPtrForOldDecl);
// Ok, delete the old function now, which is dead.
assert(F->isDeclaration() && "Shouldn't replace non-declaration");
F->eraseFromParent();
// Return the new function which has the right type.
return Entry = NewFn;
}
static bool IsZeroElementArray(const llvm::Type *Ty) {
if (const llvm::ArrayType *ATy = dyn_cast<llvm::ArrayType>(Ty))
return ATy->getNumElements() == 0;
return false;
}
llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D,
bool isDefinition) {
assert(D->hasGlobalStorage() && "Not a global variable");
// See if it is already in the map.
llvm::Constant *&Entry = GlobalDeclMap[D];
if (Entry) return Entry;
QualType ASTTy = D->getType();
const llvm::Type *Ty = getTypes().ConvertTypeForMem(ASTTy);
// Check to see if the global already exists.
llvm::GlobalVariable *GV = getModule().getGlobalVariable(D->getName(), true);
// If it doesn't already exist, just create and return an entry.
if (GV == 0) {
return Entry = new llvm::GlobalVariable(Ty, false,
llvm::GlobalValue::ExternalLinkage,
0, D->getName(), &getModule(), 0,
ASTTy.getAddressSpace());
}
// If the pointer type matches, just return it.
llvm::Type *PTy = llvm::PointerType::getUnqual(Ty);
if (PTy == GV->getType()) return Entry = GV;
// If this isn't a definition, just return it casted to the right type.
if (!isDefinition)
return Entry = llvm::ConstantExpr::getBitCast(GV, PTy);
// Otherwise, we have a definition after a prototype with the wrong type.
// GV is the GlobalVariable* for the one with the wrong type, we must make a
/// new GlobalVariable* and update everything that used GV (a declaration)
// with the new GlobalVariable* (which will be a definition).
//
// This happens if there is a prototype for a global (e.g. "extern int x[];")
// and then a definition of a different type (e.g. "int x[10];"). Start by
// making a new global of the correct type, RAUW, then steal the name.
llvm::GlobalVariable *NewGV =
new llvm::GlobalVariable(Ty, false, llvm::GlobalValue::ExternalLinkage,
0, D->getName(), &getModule(), 0,
ASTTy.getAddressSpace());
NewGV->takeName(GV);
// Replace uses of GV with the globalvalue we will endow with a body.
llvm::Constant *NewPtrForOldDecl =
llvm::ConstantExpr::getBitCast(NewGV, GV->getType());
GV->replaceAllUsesWith(NewPtrForOldDecl);
// FIXME: Update the globaldeclmap for the previous decl of this name. We
// really want a way to walk all of these, but we don't have it yet. This
// is incredibly slow!
ReplaceMapValuesWith(GV, NewPtrForOldDecl);
// Verify that GV was a declaration or something like x[] which turns into
// [0 x type].
assert((GV->isDeclaration() ||
IsZeroElementArray(GV->getType()->getElementType())) &&
"Shouldn't replace non-declaration");
// Ok, delete the old global now, which is dead.
GV->eraseFromParent();
// Return the new global which has the right type.
return Entry = NewGV;
}
void CodeGenModule::EmitFunction(const FunctionDecl *FD) {
// If this is not a prototype, emit the body.
if (FD->getBody())
CodeGenFunction(*this).GenerateCode(FD);
}
llvm::Constant *CodeGenModule::EmitGlobalInit(const Expr *Expr) {
return EmitConstantExpr(Expr);
}
void CodeGenModule::EmitGlobalVar(const FileVarDecl *D) {
// If this is just a forward declaration of the variable, don't emit it now,
// allow it to be emitted lazily on its first use.
if (D->getStorageClass() == VarDecl::Extern && D->getInit() == 0)
return;
// Get the global, forcing it to be a direct reference.
llvm::GlobalVariable *GV =
cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, true));
// Convert the initializer, or use zero if appropriate.
llvm::Constant *Init = 0;
if (D->getInit() == 0) {
Init = llvm::Constant::getNullValue(GV->getType()->getElementType());
} else if (D->getType()->isIntegerType()) {
llvm::APSInt Value(static_cast<uint32_t>(
getContext().getTypeSize(D->getInit()->getType())));
if (D->getInit()->isIntegerConstantExpr(Value, Context))
Init = llvm::ConstantInt::get(Value);
}
if (!Init)
Init = EmitGlobalInit(D->getInit());
assert(GV->getType()->getElementType() == Init->getType() &&
"Initializer codegen type mismatch!");
GV->setInitializer(Init);
if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>())
GV->setVisibility(attr->getVisibility());
// FIXME: else handle -fvisibility
// Set the llvm linkage type as appropriate.
if (D->getAttr<DLLImportAttr>())
GV->setLinkage(llvm::Function::DLLImportLinkage);
else if (D->getAttr<DLLExportAttr>())
GV->setLinkage(llvm::Function::DLLExportLinkage);
else if (D->getAttr<WeakAttr>()) {
GV->setLinkage(llvm::GlobalVariable::WeakLinkage);
} else {
// FIXME: This isn't right. This should handle common linkage and other
// stuff.
switch (D->getStorageClass()) {
case VarDecl::Auto:
case VarDecl::Register:
assert(0 && "Can't have auto or register globals");
case VarDecl::None:
if (!D->getInit())
GV->setLinkage(llvm::GlobalVariable::WeakLinkage);
break;
case VarDecl::Extern:
case VarDecl::PrivateExtern:
// todo: common
break;
case VarDecl::Static:
GV->setLinkage(llvm::GlobalVariable::InternalLinkage);
break;
}
}
}
/// EmitGlobalVarDeclarator - Emit all the global vars attached to the specified
/// declarator chain.
void CodeGenModule::EmitGlobalVarDeclarator(const FileVarDecl *D) {
for (; D; D = cast_or_null<FileVarDecl>(D->getNextDeclarator()))
EmitGlobalVar(D);
}
void CodeGenModule::UpdateCompletedType(const TagDecl *TD) {
// Make sure that this type is translated.
Types.UpdateCompletedType(TD);
}
/// getBuiltinLibFunction
llvm::Function *CodeGenModule::getBuiltinLibFunction(unsigned BuiltinID) {
if (BuiltinID > BuiltinFunctions.size())
BuiltinFunctions.resize(BuiltinID);
// Cache looked up functions. Since builtin id #0 is invalid we don't reserve
// a slot for it.
assert(BuiltinID && "Invalid Builtin ID");
llvm::Function *&FunctionSlot = BuiltinFunctions[BuiltinID-1];
if (FunctionSlot)
return FunctionSlot;
assert(Context.BuiltinInfo.isLibFunction(BuiltinID) && "isn't a lib fn");
// Get the name, skip over the __builtin_ prefix.
const char *Name = Context.BuiltinInfo.GetName(BuiltinID)+10;
// Get the type for the builtin.
QualType Type = Context.BuiltinInfo.GetBuiltinType(BuiltinID, Context);
const llvm::FunctionType *Ty =
cast<llvm::FunctionType>(getTypes().ConvertType(Type));
// FIXME: This has a serious problem with code like this:
// void abs() {}
// ... __builtin_abs(x);
// The two versions of abs will collide. The fix is for the builtin to win,
// and for the existing one to be turned into a constantexpr cast of the
// builtin. In the case where the existing one is a static function, it
// should just be renamed.
if (llvm::Function *Existing = getModule().getFunction(Name)) {
if (Existing->getFunctionType() == Ty && Existing->hasExternalLinkage())
return FunctionSlot = Existing;
assert(Existing == 0 && "FIXME: Name collision");
}
// FIXME: param attributes for sext/zext etc.
return FunctionSlot = new llvm::Function(Ty, llvm::Function::ExternalLinkage,
Name, &getModule());
}
llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys,
unsigned NumTys) {
return llvm::Intrinsic::getDeclaration(&getModule(),
(llvm::Intrinsic::ID)IID, Tys, NumTys);
}
llvm::Function *CodeGenModule::getMemCpyFn() {
if (MemCpyFn) return MemCpyFn;
llvm::Intrinsic::ID IID;
switch (Context.Target.getPointerWidth(0)) {
default: assert(0 && "Unknown ptr width");
case 32: IID = llvm::Intrinsic::memcpy_i32; break;
case 64: IID = llvm::Intrinsic::memcpy_i64; break;
}
return MemCpyFn = getIntrinsic(IID);
}
llvm::Function *CodeGenModule::getMemSetFn() {
if (MemSetFn) return MemSetFn;
llvm::Intrinsic::ID IID;
switch (Context.Target.getPointerWidth(0)) {
default: assert(0 && "Unknown ptr width");
case 32: IID = llvm::Intrinsic::memset_i32; break;
case 64: IID = llvm::Intrinsic::memset_i64; break;
}
return MemSetFn = getIntrinsic(IID);
}
llvm::Constant *CodeGenModule::
GetAddrOfConstantCFString(const std::string &str) {
llvm::StringMapEntry<llvm::Constant *> &Entry =
CFConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]);
if (Entry.getValue())
return Entry.getValue();
std::vector<llvm::Constant*> Fields;
if (!CFConstantStringClassRef) {
const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy);
Ty = llvm::ArrayType::get(Ty, 0);
CFConstantStringClassRef =
new llvm::GlobalVariable(Ty, false,
llvm::GlobalVariable::ExternalLinkage, 0,
"__CFConstantStringClassReference",
&getModule());
}
// Class pointer.
llvm::Constant *Zero = llvm::Constant::getNullValue(llvm::Type::Int32Ty);
llvm::Constant *Zeros[] = { Zero, Zero };
llvm::Constant *C =
llvm::ConstantExpr::getGetElementPtr(CFConstantStringClassRef, Zeros, 2);
Fields.push_back(C);
// Flags.
const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy);
Fields.push_back(llvm::ConstantInt::get(Ty, 1992));
// String pointer.
C = llvm::ConstantArray::get(str);
C = new llvm::GlobalVariable(C->getType(), true,
llvm::GlobalValue::InternalLinkage,
C, ".str", &getModule());
C = llvm::ConstantExpr::getGetElementPtr(C, Zeros, 2);
Fields.push_back(C);
// String length.
Ty = getTypes().ConvertType(getContext().LongTy);
Fields.push_back(llvm::ConstantInt::get(Ty, str.length()));
// The struct.
Ty = getTypes().ConvertType(getContext().getCFConstantStringType());
C = llvm::ConstantStruct::get(cast<llvm::StructType>(Ty), Fields);
llvm::GlobalVariable *GV =
new llvm::GlobalVariable(C->getType(), true,
llvm::GlobalVariable::InternalLinkage,
C, "", &getModule());
GV->setSection("__DATA,__cfstring");
Entry.setValue(GV);
return GV;
}
/// GenerateWritableString -- Creates storage for a string literal.
static llvm::Constant *GenerateStringLiteral(const std::string &str,
bool constant,
CodeGenModule &CGM) {
// Create Constant for this string literal
llvm::Constant *C=llvm::ConstantArray::get(str);
// Create a global variable for this string
C = new llvm::GlobalVariable(C->getType(), constant,
llvm::GlobalValue::InternalLinkage,
C, ".str", &CGM.getModule());
return C;
}
/// CodeGenModule::GetAddrOfConstantString -- returns a pointer to the character
/// array containing the literal. The result is pointer to array type.
llvm::Constant *CodeGenModule::GetAddrOfConstantString(const std::string &str) {
// Don't share any string literals if writable-strings is turned on.
if (Features.WritableStrings)
return GenerateStringLiteral(str, false, *this);
llvm::StringMapEntry<llvm::Constant *> &Entry =
ConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]);
if (Entry.getValue())
return Entry.getValue();
// Create a global variable for this.
llvm::Constant *C = GenerateStringLiteral(str, true, *this);
Entry.setValue(C);
return C;
}
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