wangtao
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

The saved registers weren't being processed in the correct order. This lead to 

the compact unwind claiming that one register was saved before another, which
isn't all that great in general. Process them in the natural order. Reverse the
list only when necessary for the algorithm.

llvm-svn: 146612
This commit is contained in:
Bill Wendling 2011-12-14 23:53:24 +00:00
parent 50952e9571
commit ae94fb4009
1 changed files with 14 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
llvm/lib/Target/X86/X86FrameLowering.cpp
View File

@ -351,8 +351,7 @@ void X86FrameLowering::emitCalleeSavedFrameMoves(MachineFunction &MF,
/// register. The number corresponds to the enum lists in /// register. The number corresponds to the enum lists in
/// compact_unwind_encoding.h. /// compact_unwind_encoding.h.
static int getCompactUnwindRegNum(const unsigned *CURegs, unsigned Reg) { static int getCompactUnwindRegNum(const unsigned *CURegs, unsigned Reg) {
int Idx = 1; for (int Idx = 1; *CURegs; ++CURegs, ++Idx)
for (; *CURegs; ++CURegs, ++Idx)
if (*CURegs == Reg) if (*CURegs == Reg)
return Idx; return Idx;
@ -388,12 +387,17 @@ encodeCompactUnwindRegistersWithoutFrame(unsigned SavedRegs[CU_NUM_SAVED_REGS],
}; };
const unsigned *CURegs = (Is64Bit ? CU64BitRegs : CU32BitRegs); const unsigned *CURegs = (Is64Bit ? CU64BitRegs : CU32BitRegs);
for (unsigned i = CU_NUM_SAVED_REGS - RegCount; i < CU_NUM_SAVED_REGS; ++i) { for (unsigned i = 0; i != CU_NUM_SAVED_REGS; ++i) {
int CUReg = getCompactUnwindRegNum(CURegs, SavedRegs[i]); int CUReg = getCompactUnwindRegNum(CURegs, SavedRegs[i]);
if (CUReg == -1) return ~0U; if (CUReg == -1) return ~0U;
SavedRegs[i] = CUReg; SavedRegs[i] = CUReg;
} }
// Reverse the list.
std::swap(SavedRegs[0], SavedRegs[5]);
std::swap(SavedRegs[1], SavedRegs[4]);
std::swap(SavedRegs[2], SavedRegs[3]);
uint32_t RenumRegs[CU_NUM_SAVED_REGS]; uint32_t RenumRegs[CU_NUM_SAVED_REGS];
for (unsigned i = CU_NUM_SAVED_REGS - RegCount; i < CU_NUM_SAVED_REGS; ++i) { for (unsigned i = CU_NUM_SAVED_REGS - RegCount; i < CU_NUM_SAVED_REGS; ++i) {
unsigned Countless = 0; unsigned Countless = 0;
@ -454,7 +458,7 @@ encodeCompactUnwindRegistersWithFrame(unsigned SavedRegs[CU_NUM_SAVED_REGS],
// Encode the registers in the order they were saved, 3-bits per register. The // Encode the registers in the order they were saved, 3-bits per register. The
// registers are numbered from 1 to 6. // registers are numbered from 1 to 6.
uint32_t RegEnc = 0; uint32_t RegEnc = 0;
for (int I = 5; I >= 0; --I) { for (int I = 0; I != 6; --I) {
unsigned Reg = SavedRegs[I]; unsigned Reg = SavedRegs[I];
if (Reg == 0) break; if (Reg == 0) break;
int CURegNum = getCompactUnwindRegNum(CURegs, Reg); int CURegNum = getCompactUnwindRegNum(CURegs, Reg);
@ -479,7 +483,7 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const {
bool HasFP = hasFP(MF); bool HasFP = hasFP(MF);
unsigned SavedRegs[CU_NUM_SAVED_REGS] = { 0, 0, 0, 0, 0, 0 }; unsigned SavedRegs[CU_NUM_SAVED_REGS] = { 0, 0, 0, 0, 0, 0 };
int SavedRegIdx = CU_NUM_SAVED_REGS; unsigned SavedRegIdx = 0;
unsigned OffsetSize = (Is64Bit ? 8 : 4); unsigned OffsetSize = (Is64Bit ? 8 : 4);
@ -509,9 +513,9 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const {
if (Opc == PushInstr) { if (Opc == PushInstr) {
// If there are too many saved registers, we cannot use compact encoding. // If there are too many saved registers, we cannot use compact encoding.
if (--SavedRegIdx < 0) return 0; if (SavedRegIdx >= CU_NUM_SAVED_REGS) return 0;
SavedRegs[SavedRegIdx] = MI.getOperand(0).getReg(); SavedRegs[SavedRegIdx++] = MI.getOperand(0).getReg();
StackAdjust += OffsetSize; StackAdjust += OffsetSize;
InstrOffset += PushInstrSize; InstrOffset += PushInstrSize;
} else if (Opc == MoveInstr) { } else if (Opc == MoveInstr) {
@ -523,7 +527,7 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const {
StackAdjust = 0; StackAdjust = 0;
memset(SavedRegs, 0, sizeof(SavedRegs)); memset(SavedRegs, 0, sizeof(SavedRegs));
SavedRegIdx = CU_NUM_SAVED_REGS; SavedRegIdx = 0;
InstrOffset += MoveInstrSize; InstrOffset += MoveInstrSize;
} else if (Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 || } else if (Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
Opc == X86::SUB32ri || Opc == X86::SUB32ri8) { Opc == X86::SUB32ri || Opc == X86::SUB32ri8) {
@ -586,13 +590,12 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const {
} }
// Encode the number of registers saved. // Encode the number of registers saved.
CompactUnwindEncoding |= ((CU_NUM_SAVED_REGS - SavedRegIdx) & 0x7) << 10; CompactUnwindEncoding |= (SavedRegIdx & 0x7) << 10;
// Get the encoding of the saved registers when we don't have a frame // Get the encoding of the saved registers when we don't have a frame
// pointer. // pointer.
uint32_t RegEnc = uint32_t RegEnc =
encodeCompactUnwindRegistersWithoutFrame(SavedRegs, encodeCompactUnwindRegistersWithoutFrame(SavedRegs, SavedRegIdx,
CU_NUM_SAVED_REGS - SavedRegIdx,
Is64Bit); Is64Bit);
if (RegEnc == ~0U) return 0; if (RegEnc == ~0U) return 0;