[llvm] r179820 - Use an enum instead of magic constants to improve readability.
Bill Wendling
isanbard at gmail.com
Thu Apr 18 17:06:00 PDT 2013
Author: void
Date: Thu Apr 18 19:05:59 2013
New Revision: 179820
URL: http://llvm.org/viewvc/llvm-project?rev=179820&view=rev
Log:
Use an enum instead of magic constants to improve readability.
Modified:
llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
llvm/trunk/lib/Target/X86/X86FrameLowering.h
Modified: llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FrameLowering.cpp?rev=179820&r1=179819&r2=179820&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86FrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86FrameLowering.cpp Thu Apr 18 19:05:59 2013
@@ -528,11 +528,11 @@ uint32_t X86FrameLowering::getCompactUnw
if (!MI.getFlag(MachineInstr::FrameSetup)) break;
// We don't exect any more prolog instructions.
- if (ExpectEnd) return 0x04000000;
+ if (ExpectEnd) return CU::UNWIND_MODE_DWARF;
if (Opc == PushInstr) {
// If there are too many saved registers, we cannot use compact encoding.
- if (SavedRegIdx >= CU_NUM_SAVED_REGS) return 0x04000000;
+ if (SavedRegIdx >= CU_NUM_SAVED_REGS) return CU::UNWIND_MODE_DWARF;
SavedRegs[SavedRegIdx++] = MI.getOperand(0).getReg();
StackAdjust += OffsetSize;
@@ -542,7 +542,7 @@ uint32_t X86FrameLowering::getCompactUnw
unsigned DstReg = MI.getOperand(0).getReg();
if (DstReg != FramePtr || SrcReg != StackPtr)
- return 0x04000000;
+ return CU::UNWIND_MODE_DWARF;
StackAdjust = 0;
memset(SavedRegs, 0, sizeof(SavedRegs));
@@ -552,7 +552,7 @@ uint32_t X86FrameLowering::getCompactUnw
Opc == X86::SUB32ri || Opc == X86::SUB32ri8) {
if (StackSize)
// We already have a stack size.
- return 0x04000000;
+ return CU::UNWIND_MODE_DWARF;
if (!MI.getOperand(0).isReg() ||
MI.getOperand(0).getReg() != MI.getOperand(1).getReg() ||
@@ -560,7 +560,7 @@ uint32_t X86FrameLowering::getCompactUnw
// We need this to be a stack adjustment pointer. Something like:
//
// %RSP<def> = SUB64ri8 %RSP, 48
- return 0x04000000;
+ return CU::UNWIND_MODE_DWARF;
StackSize = MI.getOperand(2).getImm() / StackDivide;
SubtractInstrIdx += InstrOffset;
@@ -574,31 +574,31 @@ uint32_t X86FrameLowering::getCompactUnw
if (HasFP) {
if ((StackAdjust & 0xFF) != StackAdjust)
// Offset was too big for compact encoding.
- return 0x04000000;
+ return CU::UNWIND_MODE_DWARF;
// Get the encoding of the saved registers when we have a frame pointer.
uint32_t RegEnc = encodeCompactUnwindRegistersWithFrame(SavedRegs, Is64Bit);
- if (RegEnc == ~0U) return 0x04000000;
+ if (RegEnc == ~0U) return CU::UNWIND_MODE_DWARF;
- CompactUnwindEncoding |= 0x01000000;
+ CompactUnwindEncoding |= CU::UNWIND_MODE_BP_FRAME;
CompactUnwindEncoding |= (StackAdjust & 0xFF) << 16;
- CompactUnwindEncoding |= RegEnc & 0x7FFF;
+ CompactUnwindEncoding |= RegEnc & CU::UNWIND_BP_FRAME_REGISTERS;
} else {
++StackAdjust;
uint32_t TotalStackSize = StackAdjust + StackSize;
if ((TotalStackSize & 0xFF) == TotalStackSize) {
// Frameless stack with a small stack size.
- CompactUnwindEncoding |= 0x02000000;
+ CompactUnwindEncoding |= CU::UNWIND_MODE_STACK_IMMD;
// Encode the stack size.
CompactUnwindEncoding |= (TotalStackSize & 0xFF) << 16;
} else {
if ((StackAdjust & 0x7) != StackAdjust)
// The extra stack adjustments are too big for us to handle.
- return 0x04000000;
+ return CU::UNWIND_MODE_DWARF;
// Frameless stack with an offset too large for us to encode compactly.
- CompactUnwindEncoding |= 0x03000000;
+ CompactUnwindEncoding |= CU::UNWIND_MODE_STACK_IND;
// Encode the offset to the nnnnnn value in the 'subl $nnnnnn, ESP'
// instruction.
@@ -616,10 +616,11 @@ uint32_t X86FrameLowering::getCompactUnw
uint32_t RegEnc =
encodeCompactUnwindRegistersWithoutFrame(SavedRegs, SavedRegIdx,
Is64Bit);
- if (RegEnc == ~0U) return 0x04000000;
+ if (RegEnc == ~0U) return CU::UNWIND_MODE_DWARF;
// Encode the register encoding.
- CompactUnwindEncoding |= RegEnc & 0x3FF;
+ CompactUnwindEncoding |=
+ RegEnc & CU::UNWIND_FRAMELESS_STACK_REG_PERMUTATION;
}
return CompactUnwindEncoding;
Modified: llvm/trunk/lib/Target/X86/X86FrameLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FrameLowering.h?rev=179820&r1=179819&r2=179820&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86FrameLowering.h (original)
+++ llvm/trunk/lib/Target/X86/X86FrameLowering.h Thu Apr 18 19:05:59 2013
@@ -19,8 +19,35 @@
#include "llvm/Target/TargetFrameLowering.h"
namespace llvm {
- class MCSymbol;
- class X86TargetMachine;
+
+namespace CU {
+
+ /// Compact unwind encoding values.
+ enum CompactUnwindEncodings {
+ /// [RE]BP based frame where [RE]BP is pused on the stack immediately after
+ /// the return address, then [RE]SP is moved to [RE]BP.
+ UNWIND_MODE_BP_FRAME = 0x01000000,
+
+ /// A frameless function with a small constant stack size.
+ UNWIND_MODE_STACK_IMMD = 0x02000000,
+
+ /// A frameless function with a large constant stack size.
+ UNWIND_MODE_STACK_IND = 0x03000000,
+
+ /// No compact unwind encoding is available.
+ UNWIND_MODE_DWARF = 0x04000000,
+
+ /// Mask for encoding the frame registers.
+ UNWIND_BP_FRAME_REGISTERS = 0x00007FFF,
+
+ /// Mask for encoding the frameless registers.
+ UNWIND_FRAMELESS_STACK_REG_PERMUTATION = 0x000003FF
+ };
+
+} // end CU namespace
+
+class MCSymbol;
+class X86TargetMachine;
class X86FrameLowering : public TargetFrameLowering {
const X86TargetMachine &TM;
More information about the llvm-commits
mailing list