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Handle global variable definitions which change the type of a definition, such as:

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extern int x[];
void foo() { x[0] = 1; }
int x[10];
void bar() { x[0] = 1; }

llvm-svn: 44509
This commit is contained in:
Chris Lattner
2007-12-02 07:09:19 +00:00
parent c48023bd5b
commit 5bcdf24a50
5 changed files with 134 additions and 75 deletions
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140
clang/CodeGen/CodeGenModule.cpp
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@@ -43,41 +43,123 @@ void CodeGenModule::ReplaceMapValuesWith(llvm::Constant *OldVal,
}
llvm::Constant *CodeGenModule::GetAddrOfGlobalDecl(const ValueDecl *D) {
// See if it is already in the map.
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;
QualType ASTTy = cast<ValueDecl>(D)->getType();
const llvm::Type *Ty = getTypes().ConvertType(ASTTy);
if (isa<FunctionDecl>(D)) {
// Check to see if the function already exists.
if (llvm::Function *F = getModule().getFunction(D->getName())) {
// If so, make sure it is the correct type.
return Entry = llvm::ConstantExpr::getBitCast(F,
llvm::PointerType::get(Ty));
}
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.
const llvm::FunctionType *FTy = cast<llvm::FunctionType>(Ty);
return Entry = new llvm::Function(FTy, llvm::Function::ExternalLinkage,
D->getName(), &getModule());
}
assert(isa<FileVarDecl>(D) && "Unknown global decl!");
if (llvm::GlobalVariable *GV = getModule().getGlobalVariable(D->getName())) {
// If so, make sure it is the correct type.
return Entry = llvm::ConstantExpr::getBitCast(GV,
llvm::PointerType::get(Ty));
// If the pointer type matches, just return it.
llvm::Type *PFTy = llvm::PointerType::get(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;
}
llvm::Constant *CodeGenModule::GetAddrOfFileVarDecl(const FileVarDecl *D,
bool isDefinition) {
// See if it is already in the map.
llvm::Constant *&Entry = GlobalDeclMap[D];
if (Entry) return Entry;
const llvm::Type *Ty = getTypes().ConvertType(D->getType());
// Check to see if the global already exists.
llvm::GlobalVariable *GV = getModule().getGlobalVariable(D->getName());
// 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());
}
return Entry = new llvm::GlobalVariable(Ty, false,
llvm::GlobalValue::ExternalLinkage,
0, D->getName(), &getModule());
// If the pointer type matches, just return it.
llvm::Type *PTy = llvm::PointerType::get(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());
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);
// Ok, delete the old global now, which is dead.
assert(GV->isDeclaration() && "Shouldn't replace non-declaration");
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())
@@ -307,14 +389,16 @@ llvm::Constant *CodeGenModule::EmitGlobalInit(const Expr *Expression) {
}
void CodeGenModule::EmitGlobalVar(const FileVarDecl *D) {
llvm::GlobalVariable *GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalDecl(D));
// If the storage class is external and there is no initializer, just leave it
// as a declaration.
// 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;
// Otherwise, convert the initializer, or use zero if appropriate.
// Get the global, forcing it to be a direct reference.
llvm::GlobalVariable *GV =
cast<llvm::GlobalVariable>(GetAddrOfFileVarDecl(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());