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- Emit DW_CFA_advance_loc and DW_CFA_def_cfa_offset codes

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This commit is contained in:
Magnus Norddahl 2018-11-29 02:37:58 +01:00 committed by drfrag
parent 4ac866aedc
commit e4ce93382b
1 changed files with 53 additions and 9 deletions
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62
src/scripting/vm/jit_runtime.cpp
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@ -330,10 +330,31 @@ static void WriteUInt8(TArray<uint8_t> &stream, uint8_t v)
static void WriteULEB128(TArray<uint8_t> &stream, uint32_t v)
{
while (true)
{
if (v < 128)
{
WriteUInt8(stream, v);
break;
}
else
{
WriteUInt8(stream, (v & 0x7f) | 0x80);
v >>= 7;
}
}
}
static void WriteSLEB128(TArray<uint8_t> &stream, int32_t v)
{
if (v >= 0)
{
WriteULEB128(stream, v);
}
else
{
// To do: sign extended version
}
}
struct FrameDesc
@ -394,6 +415,27 @@ static void WriteFDE(TArray<uint8_t> &stream, const TArray<uint8_t> &fdeInstruct
WriteLength(stream, lengthPos, length);
}
static void WriteAdvanceLoc(TArray<uint8_t> &fdeInstructions, uint64_t offset, uint64_t &lastOffset)
{
uint64_t delta = offset - lastOffset;
if (delta < (1 << 8))
{
WriteUInt8(fdeInstructions, 2); // DW_CFA_advance_loc1
WriteUInt8(fdeInstructions, delta);
}
else if (delta < (1 << 16))
{
WriteUInt8(fdeInstructions, 3); // DW_CFA_advance_loc2
WriteUInt16(fdeInstructions, delta);
}
else
{
WriteUInt8(fdeInstructions, 4); // DW_CFA_advance_loc3
WriteUInt32(fdeInstructions, delta);
}
lastOffset = offset;
}
static TArray<uint8_t> CreateUnwindInfoUnix(asmjit::CCFunc *func, unsigned int &functionStart)
{
using namespace asmjit;
@ -410,16 +452,18 @@ static TArray<uint8_t> CreateUnwindInfoUnix(asmjit::CCFunc *func, unsigned int &
X86Emitter *emitter = assembler.asEmitter();
// Build .eh_frame:
// To do: write CIE and FDE call frame instructions (see appendix D.6 "Call Frame Information Example" in the DWARF 5 spec)
// (see appendix D.6 "Call Frame Information Example" in the DWARF 5 spec)
TArray<uint8_t> cieInstructions;
TArray<uint8_t> fdeInstructions;
uint64_t lastOffset = 0;
int minInstAlignment = 4; // To do: is this correct?
int dataAlignmentFactor = -4; // To do: is this correct?
uint8_t returnAddressReg = 0; // To do: get this from asmjit
// To do: do we need to write register defaults into the CIE or does the defaults match the x64 calling convention?
// Note: this must match exactly what X86Internal::emitProlog does
X86Gp zsp = emitter->zsp(); // ESP|RSP register.
@ -436,9 +480,9 @@ static TArray<uint8_t> CreateUnwindInfoUnix(asmjit::CCFunc *func, unsigned int &
gpSaved &= ~Utils::mask(X86Gp::kIdBp);
emitter->push(zbp);
WriteAdvanceLoc(fdeInstructions, assembler.getOffset(), lastOffset);
// WriteXX(cieInstructions, UWOP_PUSH_NONVOL);
// WriteXX(cieInstructions, X86Gp::kIdBp);
// WriteXX(cieInstructions, (uint32_t)assembler.getOffset());
emitter->mov(zbp, zsp);
}
@ -452,9 +496,9 @@ static TArray<uint8_t> CreateUnwindInfoUnix(asmjit::CCFunc *func, unsigned int &
gpReg.setId(regId);
emitter->push(gpReg);
WriteAdvanceLoc(fdeInstructions, assembler.getOffset(), lastOffset);
// WriteXX(cieInstructions, UWOP_PUSH_NONVOL);
// WriteXX(cieInstructions, regId);
// WriteXX(cieInstructions, (uint32_t)assembler.getOffset());
}
}
@ -481,9 +525,9 @@ static TArray<uint8_t> CreateUnwindInfoUnix(asmjit::CCFunc *func, unsigned int &
emitter->sub(zsp, layout.getStackAdjustment());
uint32_t stackadjust = layout.getStackAdjustment();
// WriteXX(cieInstructions, UWOP_ALLOC);
// WriteXX(cieInstructions, stackadjust);
// WriteXX(cieInstructions, (uint32_t)assembler.getOffset());
WriteAdvanceLoc(fdeInstructions, assembler.getOffset(), lastOffset);
WriteUInt8(fdeInstructions, 0x0e); // DW_CFA_def_cfa_offset
WriteULEB128(fdeInstructions, stackadjust);
}
if (layout.hasDynamicAlignment() && layout.hasDsaSlotUsed())
@ -511,9 +555,9 @@ static TArray<uint8_t> CreateUnwindInfoUnix(asmjit::CCFunc *func, unsigned int &
emitter->emit(vecInst, vecBase, vecReg);
vecBase.addOffsetLo32(static_cast<int32_t>(vecSize));
WriteAdvanceLoc(fdeInstructions, assembler.getOffset(), lastOffset);
// WriteXX(cieInstructions, UWOP_SAVE_XMM128);
// WriteXX(cieInstructions, regId);
// WriteXX(cieInstructions, (uint32_t)assembler.getOffset());
}
}