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Remove FEATURE_EH_WINDOWS_X86 and all non-funclet EH code from JIT #122872

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Merged
jkotas merged 2 commits into from
Jan 5, 2026
Merged

Remove FEATURE_EH_WINDOWS_X86 and all non-funclet EH code from JIT #122872

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ddf68b8
Remove FEATURE_EH_WINDOWS_X86 and all non-funclet EH code from JIT
filipnavara Jan 5, 2026
a5005a1
Formatting fixes
filipnavara Jan 5, 2026
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8 changes: 0 additions & 8 deletions src/coreclr/jit/async.cpp
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Expand Up @@ -481,14 +481,6 @@ bool AsyncLiveness::IsLocalCaptureUnnecessary(unsigned lclNum)
return true;
}

#ifdef FEATURE_EH_WINDOWS_X86
if (lclNum == m_comp->lvaShadowSPslotsVar)
{
// Only expected to be live in handlers
return true;
}
#endif

if (lclNum == m_comp->lvaRetAddrVar)
{
return true;
Expand Down
3 changes: 0 additions & 3 deletions src/coreclr/jit/codegen.h
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Expand Up @@ -1260,9 +1260,6 @@ class CodeGen final : public CodeGenInterface
#endif // TARGET_ARM64

void genEHCatchRet(BasicBlock* block);
#if defined(FEATURE_EH_WINDOWS_X86)
void genEHFinallyOrFilterRet(BasicBlock* block);
#endif // FEATURE_EH_WINDOWS_X86

void genMultiRegStoreToSIMDLocal(GenTreeLclVar* lclNode);
void genMultiRegStoreToLocal(GenTreeLclVar* lclNode);
Expand Down
61 changes: 8 additions & 53 deletions src/coreclr/jit/codegencommon.cpp
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Expand Up @@ -501,7 +501,6 @@ void CodeGen::genMarkLabelsForCodegen()
case BBJ_CALLFINALLY:
// The finally target itself will get marked by walking the EH table, below, and marking
// all handler begins.
if (compiler->UsesCallFinallyThunks())
{
// For callfinally thunks, we need to mark the block following the callfinally/callfinallyret pair,
// as that's needed for identifying the range of the "duplicate finally" region in EH data.
Expand Down Expand Up @@ -1626,7 +1625,7 @@ void CodeGen::genJumpToThrowHlpBlk(emitJumpKind jumpKind, SpecialCodeKind codeKi
{
bool useThrowHlpBlk = compiler->fgUseThrowHelperBlocks();
#if defined(UNIX_X86_ABI)
// TODO: Is this really UNIX_X86_ABI specific? Should we guard with compiler->UsesFunclets() instead?
// TODO: Is this really UNIX_X86_ABI specific?
// Inline exception-throwing code in funclet to make it possible to unwind funclet frames.
useThrowHlpBlk = useThrowHlpBlk && (compiler->funCurrentFunc()->funKind == FUNC_ROOT);
#endif // UNIX_X86_ABI
Expand Down Expand Up @@ -4493,7 +4492,6 @@ void CodeGen::genReserveEpilog(BasicBlock* block)

void CodeGen::genReserveFuncletProlog(BasicBlock* block)
{
assert(compiler->UsesFunclets());
assert(block != nullptr);

/* Currently, no registers are live on entry to the prolog, except maybe
Expand Down Expand Up @@ -4524,7 +4522,6 @@ void CodeGen::genReserveFuncletProlog(BasicBlock* block)

void CodeGen::genReserveFuncletEpilog(BasicBlock* block)
{
assert(compiler->UsesFunclets());
assert(block != nullptr);

JITDUMP("Reserving funclet epilog IG for block " FMT_BB "\n", block->bbNum);
Expand Down Expand Up @@ -5379,31 +5376,6 @@ void CodeGen::genFnProlog()

genZeroInitFrame(untrLclHi, untrLclLo, initReg, &initRegZeroed);

#if defined(FEATURE_EH_WINDOWS_X86)
if (!compiler->UsesFunclets())
{
// when compInitMem is true the genZeroInitFrame will zero out the shadow SP slots
if (compiler->ehNeedsShadowSPslots() && !compiler->info.compInitMem)
{
// The last slot is reserved for ICodeManager::FixContext(ppEndRegion)
unsigned filterEndOffsetSlotOffs =
compiler->lvaLclStackHomeSize(compiler->lvaShadowSPslotsVar) - TARGET_POINTER_SIZE;

// Zero out the slot for nesting level 0
unsigned firstSlotOffs = filterEndOffsetSlotOffs - TARGET_POINTER_SIZE;

if (!initRegZeroed)
{
instGen_Set_Reg_To_Zero(EA_PTRSIZE, initReg);
initRegZeroed = true;
}

GetEmitter()->emitIns_S_R(ins_Store(TYP_I_IMPL), EA_PTRSIZE, initReg, compiler->lvaShadowSPslotsVar,
firstSlotOffs);
}
}
#endif // FEATURE_EH_WINDOWS_X86

genReportGenericContextArg(initReg, &initRegZeroed);

#ifdef JIT32_GCENCODER
Expand Down Expand Up @@ -5890,14 +5862,11 @@ void CodeGen::genGeneratePrologsAndEpilogs()

// Generate all the prologs and epilogs.

if (compiler->UsesFunclets())
{
// Capture the data we're going to use in the funclet prolog and epilog generation. This is
// information computed during codegen, or during function prolog generation, like
// frame offsets. It must run after main function prolog generation.
// Capture the data we're going to use in the funclet prolog and epilog generation. This is
// information computed during codegen, or during function prolog generation, like
// frame offsets. It must run after main function prolog generation.

genCaptureFuncletPrologEpilogInfo();
}
genCaptureFuncletPrologEpilogInfo();

// Walk the list of prologs and epilogs and generate them.
// We maintain a list of prolog and epilog basic blocks in
Expand Down Expand Up @@ -7101,24 +7070,10 @@ void CodeGen::genReturn(GenTree* treeNode)
#if defined(DEBUG) && defined(TARGET_XARCH)
bool doStackPointerCheck = compiler->opts.compStackCheckOnRet;

if (compiler->UsesFunclets())
// Don't do stack pointer check at the return from a funclet; only for the main function.
if (compiler->funCurrentFunc()->funKind != FUNC_ROOT)
{
// Don't do stack pointer check at the return from a funclet; only for the main function.
if (compiler->funCurrentFunc()->funKind != FUNC_ROOT)
{
doStackPointerCheck = false;
}
}
else
{
#if defined(FEATURE_EH_WINDOWS_X86)
// Don't generate stack checks for x86 finally/filter EH returns: these are not invoked
// with the same SP as the main function. See also CodeGen::genEHFinallyOrFilterRet().
if (compiler->compCurBB->KindIs(BBJ_EHFINALLYRET, BBJ_EHFAULTRET, BBJ_EHFILTERRET))
{
doStackPointerCheck = false;
}
#endif // FEATURE_EH_WINDOWS_X86
doStackPointerCheck = false;
}

genStackPointerCheck(doStackPointerCheck, compiler->lvaReturnSpCheck);
Expand Down
32 changes: 1 addition & 31 deletions src/coreclr/jit/codegenlinear.cpp
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Expand Up @@ -658,26 +658,6 @@ void CodeGen::genCodeForBBlist()
#endif // DEBUG
} //------------------ END-FOR each block of the method -------------------

#if defined(FEATURE_EH_WINDOWS_X86)
// If this is a synchronized method on x86, and we generated all the code without
// generating the "exit monitor" call, then we must have deleted the single return block
// with that call because it was dead code. We still need to report the monitor range
// to the VM in the GC info, so create a label at the very end so we have a marker for
// the monitor end range.
//
// Do this before cleaning the GC refs below; we don't want to create an IG that clears
// the `this` pointer for lvaKeepAliveAndReportThis.

if (!compiler->UsesFunclets() && (compiler->info.compFlags & CORINFO_FLG_SYNCH) &&
(compiler->syncEndEmitCookie == nullptr))
{
JITDUMP("Synchronized method with missing exit monitor call; adding final label\n");
compiler->syncEndEmitCookie =
GetEmitter()->emitAddLabel(gcInfo.gcVarPtrSetCur, gcInfo.gcRegGCrefSetCur, gcInfo.gcRegByrefSetCur);
noway_assert(compiler->syncEndEmitCookie != nullptr);
}
#endif

// There could be variables alive at this point. For example see lvaKeepAliveAndReportThis.
// This call is for cleaning the GC refs
genUpdateLife(VarSetOps::MakeEmpty(compiler));
Expand Down Expand Up @@ -848,23 +828,13 @@ BasicBlock* CodeGen::genEmitEndBlock(BasicBlock* block)
break;

case BBJ_EHCATCHRET:
assert(compiler->UsesFunclets());
genEHCatchRet(block);
FALLTHROUGH;

case BBJ_EHFINALLYRET:
case BBJ_EHFAULTRET:
case BBJ_EHFILTERRET:
if (compiler->UsesFunclets())
{
genReserveFuncletEpilog(block);
}
#if defined(FEATURE_EH_WINDOWS_X86)
else
{
genEHFinallyOrFilterRet(block);
}
#endif // FEATURE_EH_WINDOWS_X86
genReserveFuncletEpilog(block);
break;

case BBJ_SWITCH:
Expand Down
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