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JIT: fix DWARF register numbers and encoding for APX eGPRs #133918

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JIT: fix DWARF register numbers and encoding for APX eGPRs #133918

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JIT: fix DWARF register numbers and encoding for APX eGPRs
DeepakRajendrakumaran Sep 4, 2026
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DeepakRajendrakumaran Sep 30, 2026
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DeepakRajendrakumaran Oct 1, 2026
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2 changes: 1 addition & 1 deletion src/coreclr/inc/cfi.h
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ struct CFI_CODE
{
unsigned char CodeOffset;// Offset from the start of code the frame covers.
unsigned char CfiOpCode;
short DwarfReg; // Dwarf register number. 0~32 for x64.
short DwarfReg; // Dwarf register number.
int Offset;
CFI_CODE(unsigned char codeOffset, unsigned char cfiOpcode,
short dwarfReg, int offset)
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31 changes: 27 additions & 4 deletions src/coreclr/jit/unwind.cpp
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Expand Up @@ -165,17 +165,40 @@ void Compiler::unwindPushPopCFI(regNumber reg)
}

//------------------------------------------------------------------------
// Compiler::unwindPush2Pop2CFI: Record push/save of 2 registers simultaneously.
// Compiler::unwindPush2Pop2CFI: Record push/save of 2 registers simultaneously.
//
// Arguments:
// reg1 - The first register being pushed/saved.
// reg2 - The second register being pushed/saved.
//
void Compiler::unwindPush2Pop2CFI(regNumber reg1, regNumber reg2)
{
// ToDo: This is a placeholder till OS has unwind support for push2/pop2.
unwindPushPopCFI(reg1);
unwindPushPopCFI(reg2);
assert(GetEmitter()->emitGeneratingPrologOrFuncletProlog());

FuncInfoDsc* func = funCurrentFunc();
UNATIVE_OFFSET cbProlog = unwindGetCurrentOffset(func);

regMaskTP relOffsetMask = RBM_CALLEE_SAVED
#if defined(UNIX_AMD64_ABI) && ETW_EBP_FRAMED
// In case of ETW_EBP_FRAMED defined the REG_FPBASE (RBP)
// is excluded from the callee-save register list.
// Make sure the register gets PUSH unwind info in this case,
// since it is pushed as a frame register.
| RBM_FPBASE
#endif
;

createCfiCode(func, cbProlog, CFI_ADJUST_CFA_OFFSET, DWARF_REG_ILLEGAL, 2 * REGSIZE_BYTES);

if (relOffsetMask & genRegMask(reg1))
{
createCfiCode(func, cbProlog, CFI_REL_OFFSET, mapRegNumToDwarfReg(reg1), REGSIZE_BYTES);
}

if (relOffsetMask & genRegMask(reg2))
{
createCfiCode(func, cbProlog, CFI_REL_OFFSET, mapRegNumToDwarfReg(reg2), 0);
}
}

typedef jitstd::vector<CFI_CODE> CFICodeVector;
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32 changes: 16 additions & 16 deletions src/coreclr/jit/unwindamd64.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -72,52 +72,52 @@ short Compiler::mapRegNumToDwarfReg(regNumber reg)
dwarfReg = 15;
break;
case REG_R16:
dwarfReg = 16;
dwarfReg = 130;
break;
case REG_R17:
dwarfReg = 17;
dwarfReg = 131;
break;
case REG_R18:
dwarfReg = 18;
dwarfReg = 132;
break;
case REG_R19:
dwarfReg = 19;
dwarfReg = 133;
break;
case REG_R20:
dwarfReg = 20;
dwarfReg = 134;
break;
case REG_R21:
dwarfReg = 21;
dwarfReg = 135;
break;
case REG_R22:
dwarfReg = 22;
dwarfReg = 136;
break;
case REG_R23:
dwarfReg = 23;
dwarfReg = 137;
break;
case REG_R24:
dwarfReg = 24;
dwarfReg = 138;
break;
case REG_R25:
dwarfReg = 25;
dwarfReg = 139;
break;
case REG_R26:
dwarfReg = 26;
dwarfReg = 140;
break;
case REG_R27:
dwarfReg = 27;
dwarfReg = 141;
break;
case REG_R28:
dwarfReg = 28;
dwarfReg = 142;
break;
case REG_R29:
dwarfReg = 29;
dwarfReg = 143;
break;
case REG_R30:
dwarfReg = 30;
dwarfReg = 144;
break;
case REG_R31:
dwarfReg = 31;
dwarfReg = 145;
break;
default:
noway_assert(!"unexpected REG_NUM");
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4 changes: 2 additions & 2 deletions src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfFde.cs
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Expand Up @@ -80,7 +80,7 @@ private static byte[] CfiCodeToInstructions(DwarfCie cie, byte[] blobData)
{
case CFI_OPCODE.CFI_DEF_CFA_REGISTER:
cfiCode[cfiCodeOffset++] = DW_CFA_def_cfa_register;
cfiCode[cfiCodeOffset++] = (byte)dwarfReg;
cfiCodeOffset += DwarfHelper.WriteULEB128(cfiCode.AsSpan(cfiCodeOffset), (uint)dwarfReg);
break;

case CFI_OPCODE.CFI_REL_OFFSET:
Expand Down Expand Up @@ -112,7 +112,7 @@ private static byte[] CfiCodeToInstructions(DwarfCie cie, byte[] blobData)

case CFI_OPCODE.CFI_DEF_CFA:
cfiCode[cfiCodeOffset++] = DW_CFA_def_cfa;
cfiCode[cfiCodeOffset++] = (byte)dwarfReg;
cfiCodeOffset += DwarfHelper.WriteULEB128(cfiCode.AsSpan(cfiCodeOffset), (uint)dwarfReg);
cfaOffset = cfiOffset;
cfiCodeOffset += DwarfHelper.WriteULEB128(cfiCode.AsSpan(cfiCodeOffset), (uint)cfaOffset);
break;
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