[llvm] 99c6342 - [win] Fix EH Cont Guard targets when SEH personality is used (#129612)
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Fri Mar 7 09:07:51 PST 2025
Author: Daniel Paoliello
Date: 2025-03-07T09:07:47-08:00
New Revision: 99c6342b5e71098197f12066fd628865793e6300
URL: https://github.com/llvm/llvm-project/commit/99c6342b5e71098197f12066fd628865793e6300
DIFF: https://github.com/llvm/llvm-project/commit/99c6342b5e71098197f12066fd628865793e6300.diff
LOG: [win] Fix EH Cont Guard targets when SEH personality is used (#129612)
There were two issues when `/guard:ehcont` is enabled with the SEH
personality on Windows:
1. As @namazso correctly identified, we bail out of
`WinException::endFunction` early for `MSVC_TableSEH` with funclets,
expecting the exception data to be emitted in `endFunclet`, but
`endFunclet` didn't copy the EHCont metadata from the function to the
module.
2. The SEH personality requires that the basic block containing the
`catchpad` is the target, not the `catchret`.
Fixes #64585
Added:
Modified:
llvm/lib/CodeGen/AsmPrinter/WinException.cpp
llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
llvm/test/CodeGen/AArch64/arm64ec-eh.ll
llvm/test/CodeGen/AArch64/landingpad-ifcvt.ll
llvm/test/CodeGen/X86/seh-except-restore.ll
llvm/test/CodeGen/X86/win32-seh-catchpad.ll
Removed:
################################################################################
diff --git a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
index d51ac2ac89f35..062283975851a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
@@ -290,6 +290,12 @@ void WinException::endFuncletImpl() {
// functions that need it in the end anyway.
}
+ if (!MF->getEHContTargets().empty()) {
+ // Copy the function's EH Continuation targets to a module-level list.
+ EHContTargets.insert(EHContTargets.end(), MF->getEHContTargets().begin(),
+ MF->getEHContTargets().end());
+ }
+
// Switch back to the funclet start .text section now that we are done
// writing to .xdata, and emit an .seh_endproc directive to mark the end of
// the function.
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index d2df323fce638..1618f25f3908e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1970,7 +1970,11 @@ void SelectionDAGBuilder::visitCatchPad(const CatchPadInst &I) {
bool IsCoreCLR = Pers == EHPersonality::CoreCLR;
bool IsSEH = isAsynchronousEHPersonality(Pers);
MachineBasicBlock *CatchPadMBB = FuncInfo.MBB;
- if (!IsSEH)
+ if (IsSEH) {
+ // For SEH, EHCont Guard needs to know that this catchpad is a target.
+ CatchPadMBB->setIsEHContTarget(true);
+ DAG.getMachineFunction().setHasEHContTarget(true);
+ } else
CatchPadMBB->setIsEHScopeEntry();
// In MSVC C++ and CoreCLR, catchblocks are funclets and need prologues.
if (IsMSVCCXX || IsCoreCLR)
@@ -1981,8 +1985,6 @@ void SelectionDAGBuilder::visitCatchRet(const CatchReturnInst &I) {
// Update machine-CFG edge.
MachineBasicBlock *TargetMBB = FuncInfo.getMBB(I.getSuccessor());
FuncInfo.MBB->addSuccessor(TargetMBB);
- TargetMBB->setIsEHContTarget(true);
- DAG.getMachineFunction().setHasEHContTarget(true);
auto Pers = classifyEHPersonality(FuncInfo.Fn->getPersonalityFn());
bool IsSEH = isAsynchronousEHPersonality(Pers);
@@ -1996,6 +1998,10 @@ void SelectionDAGBuilder::visitCatchRet(const CatchReturnInst &I) {
return;
}
+ // For non-SEH, EHCont Guard needs to know that this catchret is a target.
+ TargetMBB->setIsEHContTarget(true);
+ DAG.getMachineFunction().setHasEHContTarget(true);
+
// Figure out the funclet membership for the catchret's successor.
// This will be used by the FuncletLayout pass to determine how to order the
// BB's.
diff --git a/llvm/test/CodeGen/AArch64/arm64ec-eh.ll b/llvm/test/CodeGen/AArch64/arm64ec-eh.ll
index 4b6bbb01c6c2d..64c4a871647f1 100644
--- a/llvm/test/CodeGen/AArch64/arm64ec-eh.ll
+++ b/llvm/test/CodeGen/AArch64/arm64ec-eh.ll
@@ -22,7 +22,6 @@ define dso_local i32 @test() #0 personality ptr @__C_specific_handler {
; CHECK-NEXT: bl "#ext"
; CHECK-NEXT: .Ltmp1:
; CHECK-NEXT: .LBB0_1:
-; CHECK-NEXT: $ehgcr_0_1:
; CHECK-NEXT: stur w0, [x29, #-4]
; CHECK-NEXT: .seh_startepilogue
; CHECK-NEXT: ldp x29, x30, [sp, #16] // 16-byte Folded Reload
@@ -32,6 +31,7 @@ define dso_local i32 @test() #0 personality ptr @__C_specific_handler {
; CHECK-NEXT: .seh_endepilogue
; CHECK-NEXT: ret
; CHECK-NEXT: .LBB0_2:
+; CHECK-NEXT: $ehgcr_0_2:
; CHECK-NEXT: mov w0, wzr
; CHECK-NEXT: b .LBB0_1
%1 = alloca i32, align 4
diff --git a/llvm/test/CodeGen/AArch64/landingpad-ifcvt.ll b/llvm/test/CodeGen/AArch64/landingpad-ifcvt.ll
index 367b4975e7558..c6dd152d7ff54 100644
--- a/llvm/test/CodeGen/AArch64/landingpad-ifcvt.ll
+++ b/llvm/test/CodeGen/AArch64/landingpad-ifcvt.ll
@@ -2,6 +2,7 @@
; Make sure this doesn't crash (and the output is sane).
; CHECK: // %__except.ret
+; CHECK-NEXT: $ehgcr_0_2:
; CHECK-NEXT: mov x0, xzr
target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"
diff --git a/llvm/test/CodeGen/X86/seh-except-restore.ll b/llvm/test/CodeGen/X86/seh-except-restore.ll
index e362f01791d06..f428a83cc2aef 100644
--- a/llvm/test/CodeGen/X86/seh-except-restore.ll
+++ b/llvm/test/CodeGen/X86/seh-except-restore.ll
@@ -48,6 +48,7 @@ return: ; preds = %entry, %__except
; CHECK: LBB0_2: # %return
; CHECK: LBB0_1: # %__except.ret
+; CHECK-NEXT: $ehgcr_0_1:
; CHECK-NEXT: movl -24(%ebp), %esp
; CHECK-NEXT: addl $12, %ebp
diff --git a/llvm/test/CodeGen/X86/win32-seh-catchpad.ll b/llvm/test/CodeGen/X86/win32-seh-catchpad.ll
index fa7335cb7bf64..832ddcab5227b 100644
--- a/llvm/test/CodeGen/X86/win32-seh-catchpad.ll
+++ b/llvm/test/CodeGen/X86/win32-seh-catchpad.ll
@@ -196,6 +196,7 @@ __except:
; CHECK-LABEL: _code_in_catchpad:
; CHECK: # %__except.ret
+; CHECK-NEXT: $ehgcr_4_1:
; CHECK-NEXT: movl -24(%ebp), %esp
; CHECK-NEXT: addl $12, %ebp
; CHECK-NEXT: movl $-1, -16(%ebp)
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