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Debug info: Refactor AsmPrinter::EmitDwarfRegOp to make the control flow 

more obvious.

llvm-svn: 202313
This commit is contained in:
Adrian Prantl 2014-02-26 23:03:37 +00:00
parent 530dde4386
commit 918b9a77ce
1 changed files with 91 additions and 61 deletions
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152
llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
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@ -871,79 +871,109 @@ void AsmPrinter::EmitFunctionBody() {
OutStreamer.AddBlankLine();
}
/// Emit a dwarf register operation.
static void emitDwarfRegOp(const AsmPrinter &AP, int Reg) {
assert(Reg >= 0);
if (Reg < 32) {
AP.OutStreamer.AddComment(dwarf::
OperationEncodingString(dwarf::DW_OP_reg0 + Reg));
AP.EmitInt8(dwarf::DW_OP_reg0 + Reg);
} else {
AP.OutStreamer.AddComment("DW_OP_regx");
AP.EmitInt8(dwarf::DW_OP_regx);
AP.OutStreamer.AddComment(Twine(Reg));
AP.EmitULEB128(Reg);
}
}
/// Emit an (double-)indirect dwarf register operation.
static void emitDwarfRegOpIndirect(const AsmPrinter &AP,
int Reg, unsigned Offset, bool Deref) {
assert(Reg >= 0);
if (Reg < 32) {
AP.OutStreamer.AddComment(dwarf::
OperationEncodingString(dwarf::DW_OP_breg0 + Reg));
AP.EmitInt8(dwarf::DW_OP_breg0 + Reg);
} else {
AP.OutStreamer.AddComment("DW_OP_bregx");
AP.EmitInt8(dwarf::DW_OP_bregx);
AP.OutStreamer.AddComment(Twine(Reg));
AP.EmitULEB128(Reg);
}
AP.EmitSLEB128(Offset);
if (Deref)
AP.EmitInt8(dwarf::DW_OP_deref);
}
/// Emit a dwarf register operation for describing
/// - a small value occupying only part of a register or
/// - a small register representing only part of a value.
static void emitDwarfRegOpPiece(const AsmPrinter &AP,
int Reg, unsigned Size, unsigned Offset) {
assert(Reg >= 0);
assert(Size > 0);
emitDwarfRegOp(AP, Reg);
// Emit Mask
if (Offset > 0) {
AP.OutStreamer.AddComment("DW_OP_bit_piece");
AP.EmitInt8(dwarf::DW_OP_bit_piece);
AP.OutStreamer.AddComment(Twine(Size));
AP.EmitULEB128(Size);
AP.OutStreamer.AddComment(Twine(Offset));
AP.EmitULEB128(Offset);
} else {
AP.OutStreamer.AddComment("DW_OP_piece");
AP.EmitInt8(dwarf::DW_OP_piece);
unsigned ByteSize = Size / 8; // Assuming 8 bits per byte.
AP.OutStreamer.AddComment(Twine(ByteSize));
AP.EmitULEB128(ByteSize);
}
}
/// EmitDwarfRegOp - Emit dwarf register operation.
void AsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc,
bool Indirect) const {
const TargetRegisterInfo *TRI = TM.getRegisterInfo();
int Reg = TRI->getDwarfRegNum(MLoc.getReg(), false);
bool isSubRegister = Reg < 0;
unsigned Idx = 0;
for (MCSuperRegIterator SR(MLoc.getReg(), TRI); SR.isValid() && Reg < 0;
++SR) {
Reg = TRI->getDwarfRegNum(*SR, false);
if (Reg >= 0)
Idx = TRI->getSubRegIndex(*SR, MLoc.getReg());
}
// FIXME: Handle cases like a super register being encoded as
// DW_OP_reg 32 DW_OP_piece 4 DW_OP_reg 33
// FIXME: We have no reasonable way of handling errors in here. The
// caller might be in the middle of an dwarf expression. We should
// probably assert that Reg >= 0 once debug info generation is more mature.
if (Reg < 0) {
// Walk up the super-register chain until we find a valid number.
for (MCSuperRegIterator SR(MLoc.getReg(), TRI); SR.isValid(); ++SR) {
Reg = TRI->getDwarfRegNum(*SR, false);
if (Reg >= 0) {
unsigned Idx = TRI->getSubRegIndex(*SR, MLoc.getReg());
unsigned Size = TRI->getSubRegIdxSize(Idx);
unsigned Offset = TRI->getSubRegIdxOffset(Idx);
emitDwarfRegOpPiece(*this, Reg, Size, Offset);
if (MLoc.isIndirect())
EmitInt8(dwarf::DW_OP_deref);
if (Indirect)
EmitInt8(dwarf::DW_OP_deref);
return;
}
// FIXME: Handle cases like a super register being encoded as
// DW_OP_reg 32 DW_OP_piece 4 DW_OP_reg 33
}
// FIXME: We have no reasonable way of handling errors in here. The
// caller might be in the middle of an dwarf expression. We should
// probably assert that Reg >= 0 once debug info generation is more mature.
OutStreamer.AddComment("nop (invalid dwarf register number)");
EmitInt8(dwarf::DW_OP_nop);
return;
}
if (MLoc.isIndirect() || Indirect) {
if (Reg < 32) {
OutStreamer.AddComment(
dwarf::OperationEncodingString(dwarf::DW_OP_breg0 + Reg));
EmitInt8(dwarf::DW_OP_breg0 + Reg);
} else {
OutStreamer.AddComment("DW_OP_bregx");
EmitInt8(dwarf::DW_OP_bregx);
OutStreamer.AddComment(Twine(Reg));
EmitULEB128(Reg);
}
EmitSLEB128(!MLoc.isIndirect() ? 0 : MLoc.getOffset());
if (MLoc.isIndirect() && Indirect)
EmitInt8(dwarf::DW_OP_deref);
} else {
if (Reg < 32) {
OutStreamer.AddComment(
dwarf::OperationEncodingString(dwarf::DW_OP_reg0 + Reg));
EmitInt8(dwarf::DW_OP_reg0 + Reg);
} else {
OutStreamer.AddComment("DW_OP_regx");
EmitInt8(dwarf::DW_OP_regx);
OutStreamer.AddComment(Twine(Reg));
EmitULEB128(Reg);
}
}
// Emit Mask
if (isSubRegister) {
unsigned Size = TRI->getSubRegIdxSize(Idx);
unsigned Offset = TRI->getSubRegIdxOffset(Idx);
if (Offset > 0) {
OutStreamer.AddComment("DW_OP_bit_piece");
EmitInt8(dwarf::DW_OP_bit_piece);
OutStreamer.AddComment(Twine(Size));
EmitULEB128(Size);
OutStreamer.AddComment(Twine(Offset));
EmitULEB128(Offset);
} else {
OutStreamer.AddComment("DW_OP_piece");
EmitInt8(dwarf::DW_OP_piece);
unsigned ByteSize = Size / 8; // Assuming 8 bits per byte.
OutStreamer.AddComment(Twine(ByteSize));
EmitULEB128(ByteSize);
}
}
if (MLoc.isIndirect())
emitDwarfRegOpIndirect(*this, Reg, MLoc.getOffset(), Indirect);
else if (Indirect)
emitDwarfRegOpIndirect(*this, Reg, 0, false);
else
emitDwarfRegOp(*this, Reg);
}
bool AsmPrinter::doFinalization(Module &M) {