[llvm] r235354 - [WinEH] Fix problem with mapping shared empty handler blocks.
Andrew Kaylor
andrew.kaylor at intel.com
Mon Apr 20 15:04:09 PDT 2015
Author: akaylor
Date: Mon Apr 20 17:04:09 2015
New Revision: 235354
URL: http://llvm.org/viewvc/llvm-project?rev=235354&view=rev
Log:
[WinEH] Fix problem with mapping shared empty handler blocks.
Differential Revision: http://reviews.llvm.org/D9125
Added:
llvm/trunk/test/CodeGen/WinEH/cppeh-shared-empty-catch.ll
Modified:
llvm/trunk/lib/CodeGen/WinEHPrepare.cpp
Modified: llvm/trunk/lib/CodeGen/WinEHPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/WinEHPrepare.cpp?rev=235354&r1=235353&r2=235354&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/WinEHPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/WinEHPrepare.cpp Mon Apr 20 17:04:09 2015
@@ -770,6 +770,15 @@ static bool isSelectorDispatch(BasicBloc
return false;
}
+static bool isCatchBlock(BasicBlock *BB) {
+ for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
+ II != IE; ++II) {
+ if (match(cast<Value>(II), m_Intrinsic<Intrinsic::eh_begincatch>()))
+ return true;
+ }
+ return false;
+}
+
static BasicBlock *createStubLandingPad(Function *Handler,
Value *PersonalityFn) {
// FIXME: Finish this!
@@ -1447,11 +1456,11 @@ void WinEHPrepare::mapLandingPadBlocks(L
}
CatchHandler *CatchAction = findCatchHandler(BB, NextBB, VisitedBlocks);
+ assert(CatchAction);
+
// See if there is any interesting code executed before the dispatch.
findCleanupHandlers(Actions, BB, CatchAction->getStartBlock());
- assert(CatchAction);
-
// When the source program contains multiple nested try blocks the catch
// handlers can get strung together in such a way that we can encounter
// a dispatch for a selector that we've already had a handler for.
@@ -1463,6 +1472,21 @@ void WinEHPrepare::mapLandingPadBlocks(L
<< CatchAction->getStartBlock()->getName() << "\n");
Actions.insertCatchHandler(CatchAction);
} else {
+ // Under some circumstances optimized IR will flow unconditionally into a
+ // handler block without checking the selector. This can only happen if
+ // the landing pad has a catch-all handler and the handler for the
+ // preceeding catch clause is identical to the catch-call handler
+ // (typically an empty catch). In this case, the handler must be shared
+ // by all remaining clauses.
+ if (isa<ConstantPointerNull>(
+ CatchAction->getSelector()->stripPointerCasts())) {
+ DEBUG(dbgs() << " Applying early catch-all handler in block "
+ << CatchAction->getStartBlock()->getName()
+ << " to all remaining clauses.\n");
+ Actions.insertCatchHandler(CatchAction);
+ return;
+ }
+
DEBUG(dbgs() << " Found extra catch dispatch in block "
<< CatchAction->getStartBlock()->getName() << "\n");
}
@@ -1517,6 +1541,18 @@ CatchHandler *WinEHPrepare::findCatchHan
CatchHandlerMap[BB] = Action;
return Action;
}
+ // If we encounter a block containing an llvm.eh.begincatch before we
+ // find a selector dispatch block, the handler is assumed to be
+ // reached unconditionally. This happens for catch-all blocks, but
+ // it can also happen for other catch handlers that have been combined
+ // with the catch-all handler during optimization.
+ if (isCatchBlock(BB)) {
+ PointerType *Int8PtrTy = Type::getInt8PtrTy(BB->getContext());
+ Constant *NullSelector = ConstantPointerNull::get(Int8PtrTy);
+ CatchHandler *Action = new CatchHandler(BB, NullSelector, nullptr);
+ CatchHandlerMap[BB] = Action;
+ return Action;
+ }
}
// Visit each successor, looking for the dispatch.
Added: llvm/trunk/test/CodeGen/WinEH/cppeh-shared-empty-catch.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WinEH/cppeh-shared-empty-catch.ll?rev=235354&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/WinEH/cppeh-shared-empty-catch.ll (added)
+++ llvm/trunk/test/CodeGen/WinEH/cppeh-shared-empty-catch.ll Mon Apr 20 17:04:09 2015
@@ -0,0 +1,110 @@
+; RUN: opt -mtriple=x86_64-pc-windows-msvc -winehprepare -S -o - < %s | FileCheck %s
+
+; This test is based on the following source, built with -O2
+;
+; void f() {
+; try {
+; g();
+; try {
+; throw;
+; } catch (int) {
+; }
+; } catch (...) {
+; }
+; }
+;
+
+; ModuleID = '<stdin>'
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc"
+
+%rtti.TypeDescriptor2 = type { i8**, i8*, [3 x i8] }
+%eh.CatchHandlerType = type { i32, i8* }
+%eh.ThrowInfo = type { i32, i32, i32, i32 }
+
+$"\01??_R0H at 8" = comdat any
+
+@"\01??_7type_info@@6B@" = external constant i8*
+@"\01??_R0H at 8" = linkonce_odr global %rtti.TypeDescriptor2 { i8** @"\01??_7type_info@@6B@", i8* null, [3 x i8] c".H\00" }, comdat
+ at llvm.eh.handlertype.H.0 = private unnamed_addr constant %eh.CatchHandlerType { i32 0, i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0H at 8" to i8*) }, section "llvm.metadata"
+
+; CHECK-LABEL: define void @"\01?f@@YAXXZ"()
+; CHECK: entry:
+; CHECK: call void (...) @llvm.frameescape()
+; CHECK: invoke void @"\01?g@@YAXXZ"()
+
+; Function Attrs: nounwind
+define void @"\01?f@@YAXXZ"() #0 {
+entry:
+ invoke void @"\01?g@@YAXXZ"()
+ to label %invoke.cont unwind label %lpad
+
+; CHECK-LABEL: invoke.cont:
+; CHECK: invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null)
+; CHECK: to label %unreachable unwind label %[[LPAD1_LABEL:lpad[0-9]+]]
+
+invoke.cont: ; preds = %entry
+ invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) #4
+ to label %unreachable unwind label %lpad1
+
+lpad: ; preds = %entry
+ %0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
+ catch i8* null
+ %1 = extractvalue { i8*, i32 } %0, 0
+ br label %catch2
+
+; Note: Even though this landing pad has two catch clauses, it only has one action because both
+; handlers do the same thing.
+; CHECK: [[LPAD1_LABEL]]:
+; CHECK: landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
+; CHECK-NEXT: catch %eh.CatchHandlerType* @llvm.eh.handlertype.H.0
+; CHECK-NEXT: catch i8* null
+; CHECK-NEXT: [[RECOVER:\%.+]] = call i8* (...) @llvm.eh.actions(i32 1, i8* null, i32 -1, i8* (i8*, i8*)* @"\01?f@@YAXXZ.catch1")
+; CHECK-NEXT: indirectbr i8* [[RECOVER]], [label %try.cont4]
+
+lpad1: ; preds = %invoke.cont
+ %2 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
+ catch %eh.CatchHandlerType* @llvm.eh.handlertype.H.0
+ catch i8* null
+ %3 = extractvalue { i8*, i32 } %2, 0
+ br label %catch2
+
+catch2: ; preds = %lpad1, %lpad
+ %exn.slot.0 = phi i8* [ %3, %lpad1 ], [ %1, %lpad ]
+ tail call void @llvm.eh.begincatch(i8* %exn.slot.0, i8* null) #3
+ tail call void @llvm.eh.endcatch() #3
+ br label %try.cont4
+
+try.cont4: ; preds = %catch, %catch2
+ ret void
+
+unreachable: ; preds = %invoke.cont
+ unreachable
+
+; CHECK: }
+}
+
+declare void @"\01?g@@YAXXZ"() #1
+
+declare i32 @__CxxFrameHandler3(...)
+
+declare void @_CxxThrowException(i8*, %eh.ThrowInfo*)
+
+; Function Attrs: nounwind readnone
+declare i32 @llvm.eh.typeid.for(i8*) #2
+
+; Function Attrs: nounwind
+declare void @llvm.eh.begincatch(i8* nocapture, i8* nocapture) #3
+
+; Function Attrs: nounwind
+declare void @llvm.eh.endcatch() #3
+
+attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #2 = { nounwind readnone }
+attributes #3 = { nounwind }
+attributes #4 = { noreturn }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 3.7.0 (trunk 235112) (llvm/trunk 235121)"}
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