Allow for the possibility that __cxa_end_catch might throw for a catch-all block
or a catch of a record type by value or reference. Also convert this to a
lazy cleanup.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@108287 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGException.cpp b/lib/CodeGen/CGException.cpp
index d3949ba..5e91adc 100644
--- a/lib/CodeGen/CGException.cpp
+++ b/lib/CodeGen/CGException.cpp
@@ -1020,18 +1020,45 @@
return LP;
}
+namespace {
+ /// A cleanup to call __cxa_end_catch. In many cases, the caught
+ /// exception type lets us state definitively that the thrown exception
+ /// type does not have a destructor. In particular:
+ /// - Catch-alls tell us nothing, so we have to conservatively
+ /// assume that the thrown exception might have a destructor.
+ /// - Catches by reference behave according to their base types.
+ /// - Catches of non-record types will only trigger for exceptions
+ /// of non-record types, which never have destructors.
+ /// - Catches of record types can trigger for arbitrary subclasses
+ /// of the caught type, so we have to assume the actual thrown
+ /// exception type might have a throwing destructor, even if the
+ /// caught type's destructor is trivial or nothrow.
+ struct CallEndCatch : EHScopeStack::LazyCleanup {
+ CallEndCatch(bool MightThrow) : MightThrow(MightThrow) {}
+ bool MightThrow;
+
+ void Emit(CodeGenFunction &CGF, bool IsForEH) {
+ if (!MightThrow) {
+ CGF.Builder.CreateCall(getEndCatchFn(CGF))->setDoesNotThrow();
+ return;
+ }
+
+ CGF.EmitCallOrInvoke(getEndCatchFn(CGF), 0, 0);
+ }
+ };
+}
+
/// Emits a call to __cxa_begin_catch and enters a cleanup to call
/// __cxa_end_catch.
-static llvm::Value *CallBeginCatch(CodeGenFunction &CGF, llvm::Value *Exn) {
+///
+/// \param EndMightThrow - true if __cxa_end_catch might throw
+static llvm::Value *CallBeginCatch(CodeGenFunction &CGF,
+ llvm::Value *Exn,
+ bool EndMightThrow) {
llvm::CallInst *Call = CGF.Builder.CreateCall(getBeginCatchFn(CGF), Exn);
Call->setDoesNotThrow();
- {
- CodeGenFunction::CleanupBlock EndCatchCleanup(CGF, NormalAndEHCleanup);
-
- // __cxa_end_catch never throws, so this can just be a call.
- CGF.Builder.CreateCall(getEndCatchFn(CGF))->setDoesNotThrow();
- }
+ CGF.EHStack.pushLazyCleanup<CallEndCatch>(NormalAndEHCleanup, EndMightThrow);
return Call;
}
@@ -1051,8 +1078,11 @@
// If we're catching by reference, we can just cast the object
// pointer to the appropriate pointer.
if (isa<ReferenceType>(CatchType)) {
+ bool EndCatchMightThrow = cast<ReferenceType>(CatchType)->getPointeeType()
+ ->isRecordType();
+
// __cxa_begin_catch returns the adjusted object pointer.
- llvm::Value *AdjustedExn = CallBeginCatch(CGF, Exn);
+ llvm::Value *AdjustedExn = CallBeginCatch(CGF, Exn, EndCatchMightThrow);
llvm::Value *ExnCast =
CGF.Builder.CreateBitCast(AdjustedExn, LLVMCatchTy, "exn.byref");
CGF.Builder.CreateStore(ExnCast, ParamAddr);
@@ -1063,7 +1093,7 @@
bool IsComplex = false;
if (!CGF.hasAggregateLLVMType(CatchType) ||
(IsComplex = CatchType->isAnyComplexType())) {
- llvm::Value *AdjustedExn = CallBeginCatch(CGF, Exn);
+ llvm::Value *AdjustedExn = CallBeginCatch(CGF, Exn, false);
// If the catch type is a pointer type, __cxa_begin_catch returns
// the pointer by value.
@@ -1098,7 +1128,7 @@
const llvm::Type *PtrTy = LLVMCatchTy->getPointerTo(0); // addrspace 0 ok
if (RD->hasTrivialCopyConstructor()) {
- llvm::Value *AdjustedExn = CallBeginCatch(CGF, Exn);
+ llvm::Value *AdjustedExn = CallBeginCatch(CGF, Exn, true);
llvm::Value *Cast = CGF.Builder.CreateBitCast(AdjustedExn, PtrTy);
CGF.EmitAggregateCopy(ParamAddr, Cast, CatchType);
return;
@@ -1131,7 +1161,7 @@
CGF.EHStack.popTerminate();
// Finally we can call __cxa_begin_catch.
- CallBeginCatch(CGF, Exn);
+ CallBeginCatch(CGF, Exn, true);
}
/// Begins a catch statement by initializing the catch variable and
@@ -1164,7 +1194,7 @@
VarDecl *CatchParam = S->getExceptionDecl();
if (!CatchParam) {
llvm::Value *Exn = CGF.Builder.CreateLoad(CGF.getExceptionSlot(), "exn");
- CallBeginCatch(CGF, Exn);
+ CallBeginCatch(CGF, Exn, true);
return;
}
@@ -1298,7 +1328,7 @@
Builder.CreateLoad(ForEHVar, "finally.endcatch");
Builder.CreateCondBr(ShouldEndCatch, EndCatchBB, CleanupContBB);
EmitBlock(EndCatchBB);
- Builder.CreateCall(EndCatchFn)->setDoesNotThrow();
+ EmitCallOrInvoke(EndCatchFn, 0, 0); // catch-all, so might throw
EmitBlock(CleanupContBB);
}
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 7293537..2992867 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -32,6 +32,7 @@
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Support/CallSite.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetData.h"
#include <cstdio>
@@ -5712,6 +5713,22 @@
llvm::BasicBlock *Block;
llvm::Value *TypeInfo;
};
+
+ struct CallObjCEndCatch : EHScopeStack::LazyCleanup {
+ CallObjCEndCatch(bool MightThrow, llvm::Value *Fn) :
+ MightThrow(MightThrow), Fn(Fn) {}
+ bool MightThrow;
+ llvm::Value *Fn;
+
+ void Emit(CodeGenFunction &CGF, bool IsForEH) {
+ if (!MightThrow) {
+ CGF.Builder.CreateCall(Fn)->setDoesNotThrow();
+ return;
+ }
+
+ CGF.EmitCallOrInvoke(Fn, 0, 0);
+ }
+ };
}
void CGObjCNonFragileABIMac::EmitTryStmt(CodeGen::CodeGenFunction &CGF,
@@ -5801,13 +5818,10 @@
Exn->setDoesNotThrow();
// Add a cleanup to leave the catch.
- {
- CodeGenFunction::CleanupBlock EndCatchBlock(CGF, NormalAndEHCleanup);
-
- // __objc_end_catch never throws.
- CGF.Builder.CreateCall(ObjCTypes.getObjCEndCatchFn())
- ->setDoesNotThrow();
- }
+ bool EndCatchMightThrow = (Handler.Variable == 0);
+ CGF.EHStack.pushLazyCleanup<CallObjCEndCatch>(NormalAndEHCleanup,
+ EndCatchMightThrow,
+ ObjCTypes.getObjCEndCatchFn());
// Bind the catch parameter if it exists.
if (const VarDecl *CatchParam = Handler.Variable) {
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index ce3453a..90a5421 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -207,6 +207,22 @@
// Variadic templates would make this not terrible.
/// Push a lazily-created cleanup on the stack.
+ template <class T>
+ void pushLazyCleanup(CleanupKind Kind) {
+ void *Buffer = pushLazyCleanup(Kind, sizeof(T));
+ LazyCleanup *Obj = new(Buffer) T();
+ (void) Obj;
+ }
+
+ /// Push a lazily-created cleanup on the stack.
+ template <class T, class A0>
+ void pushLazyCleanup(CleanupKind Kind, A0 a0) {
+ void *Buffer = pushLazyCleanup(Kind, sizeof(T));
+ LazyCleanup *Obj = new(Buffer) T(a0);
+ (void) Obj;
+ }
+
+ /// Push a lazily-created cleanup on the stack.
template <class T, class A0, class A1>
void pushLazyCleanup(CleanupKind Kind, A0 a0, A1 a1) {
void *Buffer = pushLazyCleanup(Kind, sizeof(T));