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-rw-r--r--lib/CodeGen/ELFWriter.cpp111
-rw-r--r--lib/CodeGen/ELFWriter.h4
2 files changed, 87 insertions, 28 deletions
diff --git a/lib/CodeGen/ELFWriter.cpp b/lib/CodeGen/ELFWriter.cpp
index ca79d9d..ff41338 100644
--- a/lib/CodeGen/ELFWriter.cpp
+++ b/lib/CodeGen/ELFWriter.cpp
@@ -497,32 +497,21 @@ void ELFWriter::EmitGlobalConstant(const Constant *CV, ELFSection &GblS) {
EmitGlobalConstant(CP->getOperand(I), GblS);
return;
} else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
- switch (CE->getOpcode()) {
- case Instruction::BitCast: {
- EmitGlobalConstant(CE->getOperand(0), GblS);
- return;
- }
- case Instruction::GetElementPtr: {
- const Constant *ptrVal = CE->getOperand(0);
- SmallVector<Value*, 8> idxVec(CE->op_begin()+1, CE->op_end());
- int64_t Offset = TD->getIndexedOffset(ptrVal->getType(), &idxVec[0],
- idxVec.size());
- EmitGlobalDataRelocation(cast<const GlobalValue>(ptrVal),
- TD->getTypeAllocSize(ptrVal->getType()),
- GblS, Offset);
- return;
- }
- case Instruction::IntToPtr: {
- Constant *Op = CE->getOperand(0);
- Op = ConstantExpr::getIntegerCast(Op, TD->getIntPtrType(), false/*ZExt*/);
+ // Resolve a constant expression which returns a (Constant, Offset)
+ // pair. If 'Res.first' is a GlobalValue, emit a relocation with
+ // the offset 'Res.second', otherwise emit a global constant like
+ // it is always done for not contant expression types.
+ CstExprResTy Res = ResolveConstantExpr(CE);
+ const Constant *Op = Res.first;
+
+ if (isa<GlobalValue>(Op))
+ EmitGlobalDataRelocation(cast<const GlobalValue>(Op),
+ TD->getTypeAllocSize(Op->getType()),
+ GblS, Res.second);
+ else
EmitGlobalConstant(Op, GblS);
- return;
- }
- }
- std::string msg(CE->getOpcodeName());
- raw_string_ostream ErrorMsg(msg);
- ErrorMsg << ": Unsupported ConstantExpr type";
- llvm_report_error(ErrorMsg.str());
+
+ return;
} else if (CV->getType()->getTypeID() == Type::PointerTyID) {
// Fill the data entry with zeros or emit a relocation entry
if (isa<ConstantPointerNull>(CV))
@@ -544,8 +533,77 @@ void ELFWriter::EmitGlobalConstant(const Constant *CV, ELFSection &GblS) {
llvm_report_error(ErrorMsg.str());
}
+// ResolveConstantExpr - Resolve the constant expression until it stop
+// yielding other constant expressions.
+CstExprResTy ELFWriter::ResolveConstantExpr(const Constant *CV) {
+ const TargetData *TD = TM.getTargetData();
+
+ // There ins't constant expression inside others anymore
+ if (!isa<ConstantExpr>(CV))
+ return std::make_pair(CV, 0);
+
+ const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
+ switch (CE->getOpcode()) {
+ case Instruction::BitCast:
+ return ResolveConstantExpr(CE->getOperand(0));
+
+ case Instruction::GetElementPtr: {
+ const Constant *ptrVal = CE->getOperand(0);
+ SmallVector<Value*, 8> idxVec(CE->op_begin()+1, CE->op_end());
+ int64_t Offset = TD->getIndexedOffset(ptrVal->getType(), &idxVec[0],
+ idxVec.size());
+ return std::make_pair(ptrVal, Offset);
+ }
+ case Instruction::IntToPtr: {
+ Constant *Op = CE->getOperand(0);
+ Op = ConstantExpr::getIntegerCast(Op, TD->getIntPtrType(), false/*ZExt*/);
+ return ResolveConstantExpr(Op);
+ }
+ case Instruction::PtrToInt: {
+ Constant *Op = CE->getOperand(0);
+ const Type *Ty = CE->getType();
+
+ // We can emit the pointer value into this slot if the slot is an
+ // integer slot greater or equal to the size of the pointer.
+ if (TD->getTypeAllocSize(Ty) == TD->getTypeAllocSize(Op->getType()))
+ return ResolveConstantExpr(Op);
+
+ llvm_unreachable("Integer size less then pointer size");
+ }
+ case Instruction::Add:
+ case Instruction::Sub: {
+ // Only handle cases where there's a constant expression with GlobalValue
+ // as first operand and ConstantInt as second, which are the cases we can
+ // solve direclty using a relocation entry. GlobalValue=Op0, CstInt=Op1
+ // 1) Instruction::Add => (global) + CstInt
+ // 2) Instruction::Sub => (global) + -CstInt
+ const Constant *Op0 = CE->getOperand(0);
+ const Constant *Op1 = CE->getOperand(1);
+ assert(isa<ConstantInt>(Op1) && "Op1 must be a ConstantInt");
+
+ CstExprResTy Res = ResolveConstantExpr(Op0);
+ assert(isa<GlobalValue>(Res.first) && "Op0 must be a GlobalValue");
+
+ const APInt &RHS = cast<ConstantInt>(Op1)->getValue();
+ switch (CE->getOpcode()) {
+ case Instruction::Add:
+ return std::make_pair(Res.first, RHS.getSExtValue());
+ case Instruction::Sub:
+ return std::make_pair(Res.first, (-RHS).getSExtValue());
+ }
+ }
+ }
+
+ std::string msg(CE->getOpcodeName());
+ raw_string_ostream ErrorMsg(msg);
+ ErrorMsg << ": Unsupported ConstantExpr type";
+ llvm_report_error(ErrorMsg.str());
+
+ return std::make_pair(CV, 0); // silence warning
+}
+
void ELFWriter::EmitGlobalDataRelocation(const GlobalValue *GV, unsigned Size,
- ELFSection &GblS, uint64_t Offset) {
+ ELFSection &GblS, int64_t Offset) {
// Create the relocation entry for the global value
MachineRelocation MR =
MachineRelocation::getGV(GblS.getCurrentPCOffset(),
@@ -868,7 +926,6 @@ void ELFWriter::EmitStringTable(const std::string &ModuleName) {
std::string Name;
if (Sym.isGlobalValue())
- // Use the name mangler to uniquify the LLVM symbol.
Name.append(Mang->getMangledName(Sym.getGlobalValue()));
else if (Sym.isExternalSym())
Name.append(Sym.getExternalSymbol());
diff --git a/lib/CodeGen/ELFWriter.h b/lib/CodeGen/ELFWriter.h
index 362c278..ae14313 100644
--- a/lib/CodeGen/ELFWriter.h
+++ b/lib/CodeGen/ELFWriter.h
@@ -43,6 +43,7 @@ namespace llvm {
typedef std::vector<ELFSection*>::iterator ELFSectionIter;
typedef SetVector<const GlobalValue*>::const_iterator PendingGblsIter;
typedef SetVector<const char *>::const_iterator PendingExtsIter;
+ typedef std::pair<const Constant *, int64_t> CstExprResTy;
/// ELFWriter - This class implements the common target-independent code for
/// writing ELF files. Targets should derive a class from this to
@@ -251,7 +252,7 @@ namespace llvm {
ELFSection &GblS);
void EmitGlobalConstantLargeInt(const ConstantInt *CI, ELFSection &S);
void EmitGlobalDataRelocation(const GlobalValue *GV, unsigned Size,
- ELFSection &GblS, uint64_t Offset = 0);
+ ELFSection &GblS, int64_t Offset = 0);
bool EmitSpecialLLVMGlobal(const GlobalVariable *GV);
void EmitXXStructorList(Constant *List, ELFSection &Xtor);
void EmitRelocations();
@@ -265,6 +266,7 @@ namespace llvm {
void RelocateField(BinaryObject &BO, uint32_t Offset, int64_t Value,
unsigned Size);
unsigned SortSymbols();
+ CstExprResTy ResolveConstantExpr(const Constant *CV);
};
}
generated by cgit v1.1 at 2025-03-19 05:40:02 +0000