Debug Info: Simplify Frame Index handling in DBG_VALUE Machine Instructions
Rather than using the full power of target-specific addressing modes in
DBG_VALUEs with Frame Indicies, simply use Frame Index + Offset. This
reduces the complexity of debug info handling down to two
representations of values (reg+offset and frame index+offset) rather
than three or four.
Ideally we could ensure that frame indicies had been eliminated by the
time we reached an assembly or dwarf generation, but I haven't spent the
time to figure out where the FIs are leaking through into that & whether
there's a good place to convert them. Some FI+offset=>reg+offset
conversion is done (see PrologEpilogInserter, for example) which is
necessary for some SelectionDAG assumptions about registers, I believe,
but it might be possible to make this a more thorough conversion &
ensure there are no remaining FIs no matter how instruction selection
is performed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184066 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index c3b6c10..9e8f9aa 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -1525,43 +1525,23 @@
// Check if variable is described by a DBG_VALUE instruction.
if (const MachineInstr *DVInsn = DV->getMInsn()) {
bool updated = false;
- if (DVInsn->getNumOperands() == 3) {
- if (DVInsn->getOperand(0).isReg()) {
- const MachineOperand RegOp = DVInsn->getOperand(0);
- const TargetRegisterInfo *TRI = Asm->TM.getRegisterInfo();
- if (DVInsn->getOperand(1).isImm() &&
- TRI->getFrameRegister(*Asm->MF) == RegOp.getReg()) {
- unsigned FrameReg = 0;
- const TargetFrameLowering *TFI = Asm->TM.getFrameLowering();
- int Offset =
- TFI->getFrameIndexReference(*Asm->MF,
- DVInsn->getOperand(1).getImm(),
- FrameReg);
- MachineLocation Location(FrameReg, Offset);
- addVariableAddress(DV, VariableDie, Location);
-
- } else if (RegOp.getReg())
- addVariableAddress(DV, VariableDie,
- MachineLocation(RegOp.getReg()));
- updated = true;
- }
- else if (DVInsn->getOperand(0).isImm())
- updated =
- addConstantValue(VariableDie, DVInsn->getOperand(0),
- DV->getType());
- else if (DVInsn->getOperand(0).isFPImm())
- updated =
- addConstantFPValue(VariableDie, DVInsn->getOperand(0));
- else if (DVInsn->getOperand(0).isCImm())
- updated =
- addConstantValue(VariableDie,
- DVInsn->getOperand(0).getCImm(),
- DV->getType().isUnsignedDIType());
- } else {
- addVariableAddress(DV, VariableDie,
- Asm->getDebugValueLocation(DVInsn));
+ assert(DVInsn->getNumOperands() == 3);
+ if (DVInsn->getOperand(0).isReg()) {
+ const MachineOperand RegOp = DVInsn->getOperand(0);
+ if (int64_t Offset = DVInsn->getOperand(1).getImm()) {
+ MachineLocation Location(RegOp.getReg(), Offset);
+ addVariableAddress(DV, VariableDie, Location);
+ } else if (RegOp.getReg())
+ addVariableAddress(DV, VariableDie, MachineLocation(RegOp.getReg()));
updated = true;
- }
+ } else if (DVInsn->getOperand(0).isImm())
+ updated =
+ addConstantValue(VariableDie, DVInsn->getOperand(0), DV->getType());
+ else if (DVInsn->getOperand(0).isFPImm())
+ updated = addConstantFPValue(VariableDie, DVInsn->getOperand(0));
+ else if (DVInsn->getOperand(0).isCImm())
+ updated = addConstantValue(VariableDie, DVInsn->getOperand(0).getCImm(),
+ DV->getType().isUnsignedDIType());
if (!updated) {
// If variableDie is not updated then DBG_VALUE instruction does not
// have valid variable info.