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/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 9b39264..842381b 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -42,6 +42,7 @@
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Timer.h"
#include "llvm/Target/Mangler.h"
+#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
@@ -591,8 +592,17 @@
} else if (MI->getOperand(0).isCImm()) {
MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
} else {
- assert(MI->getOperand(0).isReg() && "Unknown operand type");
- unsigned Reg = MI->getOperand(0).getReg();
+ unsigned Reg;
+ if (MI->getOperand(0).isReg()) {
+ Reg = MI->getOperand(0).getReg();
+ Deref = Offset != 0; // FIXME: use a better sentinel value so that deref
+ // of a reg with a zero offset is valid
+ } else {
+ assert(MI->getOperand(0).isFI() && "Unknown operand type");
+ const TargetFrameLowering *TFI = AP.TM.getFrameLowering();
+ Offset += TFI->getFrameIndexReference(*AP.MF, MI->getOperand(0).getIndex(), Reg);
+ Deref = true;
+ }
if (Reg == 0) {
// Suppress offset, it is not meaningful here.
OS << "undef";
@@ -600,8 +610,6 @@
AP.OutStreamer.EmitRawText(OS.str());
return true;
}
- Deref = Offset != 0; // FIXME: use a better sentinel value so that deref of
- // a reg with a zero offset is valid
if (Deref)
OS << '[';
OS << AP.TM.getRegisterInfo()->getName(Reg);
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.
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 7915e2f..23eb569 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1170,10 +1170,7 @@
const MachineInstr *MI) {
const MDNode *Var = MI->getOperand(MI->getNumOperands() - 1).getMetadata();
- if (MI->getNumOperands() != 3) {
- MachineLocation MLoc = Asm->getDebugValueLocation(MI);
- return DotDebugLocEntry(FLabel, SLabel, MLoc, Var);
- }
+ assert(MI->getNumOperands() == 3);
if (MI->getOperand(0).isReg() && MI->getOperand(1).isImm()) {
MachineLocation MLoc;
// TODO: Currently an offset of 0 in a DBG_VALUE means