Assorted fixes for Win64 EH unwind info emission:
- Flip order of bitfields. This gets our output matching GAS.
- Handle case where the end of the prolog wasn't specified.
- If the resulting unwind info struct is less than 8 bytes, pad to 8 bytes.
Add a test for the latter two.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132188 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCWin64EH.cpp b/lib/MC/MCWin64EH.cpp
index c7141f7..018bb7c 100644
--- a/lib/MC/MCWin64EH.cpp
+++ b/lib/MC/MCWin64EH.cpp
@@ -63,17 +63,17 @@
MCWin64EHInstruction &inst) {
uint8_t b1, b2;
uint16_t w;
- b2 = (inst.getOperation() & 0x0F) << 4;
+ b2 = (inst.getOperation() & 0x0F);
switch (inst.getOperation()) {
case Win64EH::UOP_PushNonVol:
EmitAbsDifference(streamer, inst.getLabel(), begin);
- b2 |= inst.getRegister() & 0x0F;
+ b2 |= (inst.getRegister() & 0x0F) << 4;
streamer.EmitIntValue(b2, 1);
break;
case Win64EH::UOP_AllocLarge:
EmitAbsDifference(streamer, inst.getLabel(), begin);
if (inst.getSize() > 512*1024-8) {
- b2 |= 1;
+ b2 |= 0x10;
streamer.EmitIntValue(b2, 1);
w = inst.getSize() & 0xFFF8;
streamer.EmitIntValue(w, 2);
@@ -85,7 +85,7 @@
streamer.EmitIntValue(w, 2);
break;
case Win64EH::UOP_AllocSmall:
- b2 |= ((inst.getSize()-8) >> 3) & 0x0F;
+ b2 |= (((inst.getSize()-8) >> 3) & 0x0F) << 4;
EmitAbsDifference(streamer, inst.getLabel(), begin);
streamer.EmitIntValue(b2, 1);
break;
@@ -96,7 +96,7 @@
break;
case Win64EH::UOP_SaveNonVol:
case Win64EH::UOP_SaveXMM128:
- b2 |= inst.getRegister() & 0x0F;
+ b2 |= (inst.getRegister() & 0x0F) << 4;
EmitAbsDifference(streamer, inst.getLabel(), begin);
streamer.EmitIntValue(b2, 1);
w = inst.getOffset() >> 3;
@@ -106,7 +106,7 @@
break;
case Win64EH::UOP_SaveNonVolBig:
case Win64EH::UOP_SaveXMM128Big:
- b2 |= inst.getRegister() & 0x0F;
+ b2 |= (inst.getRegister() & 0x0F) << 4;
EmitAbsDifference(streamer, inst.getLabel(), begin);
streamer.EmitIntValue(b2, 1);
if (inst.getOperation() == Win64EH::UOP_SaveXMM128Big)
@@ -119,7 +119,7 @@
break;
case Win64EH::UOP_PushMachFrame:
if (inst.isPushCodeFrame())
- b2 |= 1;
+ b2 |= 0x10;
EmitAbsDifference(streamer, inst.getLabel(), begin);
streamer.EmitIntValue(b2, 1);
break;
@@ -143,21 +143,24 @@
MCContext &context = streamer.getContext();
streamer.EmitValueToAlignment(4);
// Upper 3 bits are the version number (currently 1).
- uint8_t flags = 0x20;
+ uint8_t flags = 0x01;
info->Symbol = context.CreateTempSymbol();
streamer.EmitLabel(info->Symbol);
if (info->ChainedParent)
- flags |= Win64EH::UNW_ChainInfo;
+ flags |= Win64EH::UNW_ChainInfo << 3;
else {
if (info->HandlesUnwind)
- flags |= Win64EH::UNW_TerminateHandler;
+ flags |= Win64EH::UNW_TerminateHandler << 3;
if (info->HandlesExceptions)
- flags |= Win64EH::UNW_ExceptionHandler;
+ flags |= Win64EH::UNW_ExceptionHandler << 3;
}
streamer.EmitIntValue(flags, 1);
- EmitAbsDifference(streamer, info->PrologEnd, info->Begin);
+ if (info->PrologEnd)
+ EmitAbsDifference(streamer, info->PrologEnd, info->Begin);
+ else
+ streamer.EmitIntValue(0, 1);
uint8_t numCodes = CountOfUnwindCodes(info->Instructions);
streamer.EmitIntValue(numCodes, 1);
@@ -166,8 +169,8 @@
if (info->LastFrameInst >= 0) {
MCWin64EHInstruction &frameInst = info->Instructions[info->LastFrameInst];
assert(frameInst.getOperation() == Win64EH::UOP_SetFPReg);
- frame = ((frameInst.getRegister() & 0x0F) << 4) |
- ((frameInst.getOffset() >> 4) & 0x0F);
+ frame = (frameInst.getRegister() & 0x0F) |
+ (frameInst.getOffset() & 0xF0);
}
streamer.EmitIntValue(frame, 1);
@@ -179,11 +182,21 @@
EmitUnwindCode(streamer, info->Begin, inst);
}
- if (flags & Win64EH::UNW_ChainInfo)
+ if (flags & (Win64EH::UNW_ChainInfo << 3))
EmitRuntimeFunction(streamer, info->ChainedParent);
- else if (flags &(Win64EH::UNW_TerminateHandler|Win64EH::UNW_ExceptionHandler))
+ else if (flags &
+ ((Win64EH::UNW_TerminateHandler|Win64EH::UNW_ExceptionHandler) << 3))
streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler, context),
4);
+ else if (numCodes < 2) {
+ // The minimum size of an UNWIND_INFO struct is 8 bytes. If we're not
+ // a chained unwind info, if there is no handler, and if there are fewer
+ // than 2 slots used in the unwind code array, we have to pad to 8 bytes.
+ if (numCodes == 1)
+ streamer.EmitIntValue(0, 2);
+ else
+ streamer.EmitIntValue(0, 4);
+ }
}
void MCWin64EHUnwindEmitter::EmitUnwindInfo(MCStreamer &streamer,