[MS ABI] Hook clang up to the new EH instructions
The new EH instructions make it possible for LLVM to generate .xdata
tables that the MSVC personality routines will be happy about. Because
this is experimental, hide it behind a -cc1 flag (-fnew-ms-eh).
Differential Revision: http://reviews.llvm.org/D11405
llvm-svn: 243767
diff --git a/clang/lib/CodeGen/CGCleanup.cpp b/clang/lib/CodeGen/CGCleanup.cpp
index 3d4c485..ef5a98e 100644
--- a/clang/lib/CodeGen/CGCleanup.cpp
+++ b/clang/lib/CodeGen/CGCleanup.cpp
@@ -247,6 +247,13 @@
InnermostEHScope = stable_begin();
}
+void EHScopeStack::pushCatchEnd(llvm::BasicBlock *CatchEndBlockBB) {
+ char *Buffer = allocate(EHCatchEndScope::getSize());
+ auto *CES = new (Buffer) EHCatchEndScope(InnermostEHScope);
+ CES->setCachedEHDispatchBlock(CatchEndBlockBB);
+ InnermostEHScope = stable_begin();
+}
+
/// Remove any 'null' fixups on the stack. However, we can't pop more
/// fixups than the fixup depth on the innermost normal cleanup, or
/// else fixups that we try to add to that cleanup will end up in the
@@ -896,6 +903,14 @@
CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
EmitBlock(EHEntry);
+ llvm::BasicBlock *NextAction = getEHDispatchBlock(EHParent);
+ if (CGM.getCodeGenOpts().NewMSEH &&
+ EHPersonality::get(*this).isMSVCPersonality()) {
+ if (NextAction)
+ Builder.CreateCleanupPad(VoidTy, NextAction);
+ else
+ Builder.CreateCleanupPad(VoidTy, {});
+ }
// We only actually emit the cleanup code if the cleanup is either
// active or was used before it was deactivated.
@@ -905,7 +920,10 @@
EmitCleanup(*this, Fn, cleanupFlags, EHActiveFlag);
}
- Builder.CreateBr(getEHDispatchBlock(EHParent));
+ if (CGM.getCodeGenOpts().NewMSEH && EHPersonality::get(*this).isMSVCPersonality())
+ Builder.CreateCleanupRet(NextAction);
+ else
+ Builder.CreateBr(NextAction);
Builder.restoreIP(SavedIP);
diff --git a/clang/lib/CodeGen/CGCleanup.h b/clang/lib/CodeGen/CGCleanup.h
index 8338691..dcbc40d 100644
--- a/clang/lib/CodeGen/CGCleanup.h
+++ b/clang/lib/CodeGen/CGCleanup.h
@@ -40,9 +40,9 @@
class CommonBitFields {
friend class EHScope;
- unsigned Kind : 2;
+ unsigned Kind : 3;
};
- enum { NumCommonBits = 2 };
+ enum { NumCommonBits = 3 };
protected:
class CatchBitFields {
@@ -81,7 +81,7 @@
/// The number of fixups required by enclosing scopes (not including
/// this one). If this is the top cleanup scope, all the fixups
/// from this index onwards belong to this scope.
- unsigned FixupDepth : 32 - 18 - NumCommonBits; // currently 13
+ unsigned FixupDepth : 32 - 18 - NumCommonBits; // currently 12
};
class FilterBitFields {
@@ -99,7 +99,7 @@
};
public:
- enum Kind { Cleanup, Catch, Terminate, Filter };
+ enum Kind { Cleanup, Catch, Terminate, Filter, CatchEnd };
EHScope(Kind kind, EHScopeStack::stable_iterator enclosingEHScope)
: CachedLandingPad(nullptr), CachedEHDispatchBlock(nullptr),
@@ -466,6 +466,17 @@
}
};
+class EHCatchEndScope : public EHScope {
+public:
+ EHCatchEndScope(EHScopeStack::stable_iterator enclosingEHScope)
+ : EHScope(CatchEnd, enclosingEHScope) {}
+ static size_t getSize() { return sizeof(EHCatchEndScope); }
+
+ static bool classof(const EHScope *scope) {
+ return scope->getKind() == CatchEnd;
+ }
+};
+
/// A non-stable pointer into the scope stack.
class EHScopeStack::iterator {
char *Ptr;
@@ -503,6 +514,10 @@
case EHScope::Terminate:
Size = EHTerminateScope::getSize();
break;
+
+ case EHScope::CatchEnd:
+ Size = EHCatchEndScope::getSize();
+ break;
}
Ptr += llvm::RoundUpToAlignment(Size, ScopeStackAlignment);
return *this;
@@ -551,6 +566,14 @@
deallocate(EHTerminateScope::getSize());
}
+inline void EHScopeStack::popCatchEnd() {
+ assert(!empty() && "popping exception stack when not empty");
+
+ EHCatchEndScope &scope = cast<EHCatchEndScope>(*begin());
+ InnermostEHScope = scope.getEnclosingEHScope();
+ deallocate(EHCatchEndScope::getSize());
+}
+
inline EHScopeStack::iterator EHScopeStack::find(stable_iterator sp) const {
assert(sp.isValid() && "finding invalid savepoint");
assert(sp.Size <= stable_begin().Size && "finding savepoint after pop");
@@ -588,6 +611,13 @@
static const EHPersonality MSVC_except_handler;
static const EHPersonality MSVC_C_specific_handler;
static const EHPersonality MSVC_CxxFrameHandler3;
+
+ bool isMSVCPersonality() const {
+ return this == &MSVC_except_handler || this == &MSVC_C_specific_handler ||
+ this == &MSVC_CxxFrameHandler3;
+ }
+
+ bool isMSVCXXPersonality() const { return this == &MSVC_CxxFrameHandler3; }
};
}
}
diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
index d0e86ae..16dc7d1 100644
--- a/clang/lib/CodeGen/CGException.cpp
+++ b/clang/lib/CodeGen/CGException.cpp
@@ -559,6 +559,10 @@
llvm::BasicBlock *
CodeGenFunction::getEHDispatchBlock(EHScopeStack::stable_iterator si) {
+ if (CGM.getCodeGenOpts().NewMSEH &&
+ EHPersonality::get(*this).isMSVCPersonality())
+ return getMSVCDispatchBlock(si);
+
// The dispatch block for the end of the scope chain is a block that
// just resumes unwinding.
if (si == EHStack.stable_end())
@@ -595,12 +599,58 @@
case EHScope::Terminate:
dispatchBlock = getTerminateHandler();
break;
+
+ case EHScope::CatchEnd:
+ llvm_unreachable("CatchEnd unnecessary for Itanium!");
}
scope.setCachedEHDispatchBlock(dispatchBlock);
}
return dispatchBlock;
}
+llvm::BasicBlock *
+CodeGenFunction::getMSVCDispatchBlock(EHScopeStack::stable_iterator SI) {
+ // Returning nullptr indicates that the previous dispatch block should unwind
+ // to caller.
+ if (SI == EHStack.stable_end())
+ return nullptr;
+
+ // Otherwise, we should look at the actual scope.
+ EHScope &EHS = *EHStack.find(SI);
+
+ llvm::BasicBlock *DispatchBlock = EHS.getCachedEHDispatchBlock();
+ if (DispatchBlock)
+ return DispatchBlock;
+
+ if (EHS.getKind() == EHScope::Terminate)
+ DispatchBlock = getTerminateHandler();
+ else
+ DispatchBlock = createBasicBlock();
+ CGBuilderTy Builder(DispatchBlock);
+
+ switch (EHS.getKind()) {
+ case EHScope::Catch:
+ DispatchBlock->setName("catch.dispatch");
+ break;
+
+ case EHScope::Cleanup:
+ DispatchBlock->setName("ehcleanup");
+ break;
+
+ case EHScope::Filter:
+ llvm_unreachable("exception specifications not handled yet!");
+
+ case EHScope::Terminate:
+ DispatchBlock->setName("terminate");
+ break;
+
+ case EHScope::CatchEnd:
+ llvm_unreachable("CatchEnd dispatch block missing!");
+ }
+ EHS.setCachedEHDispatchBlock(DispatchBlock);
+ return DispatchBlock;
+}
+
/// Check whether this is a non-EH scope, i.e. a scope which doesn't
/// affect exception handling. Currently, the only non-EH scopes are
/// normal-only cleanup scopes.
@@ -611,6 +661,7 @@
case EHScope::Filter:
case EHScope::Catch:
case EHScope::Terminate:
+ case EHScope::CatchEnd:
return false;
}
@@ -636,8 +687,19 @@
llvm::BasicBlock *LP = EHStack.begin()->getCachedLandingPad();
if (LP) return LP;
- // Build the landing pad for this scope.
- LP = EmitLandingPad();
+ const EHPersonality &Personality = EHPersonality::get(*this);
+
+ if (!CurFn->hasPersonalityFn())
+ CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
+
+ if (CGM.getCodeGenOpts().NewMSEH && Personality.isMSVCPersonality()) {
+ // We don't need separate landing pads in the MSVC model.
+ LP = getEHDispatchBlock(EHStack.getInnermostEHScope());
+ } else {
+ // Build the landing pad for this scope.
+ LP = EmitLandingPad();
+ }
+
assert(LP);
// Cache the landing pad on the innermost scope. If this is a
@@ -658,6 +720,9 @@
case EHScope::Terminate:
return getTerminateLandingPad();
+ case EHScope::CatchEnd:
+ llvm_unreachable("CatchEnd unnecessary for Itanium!");
+
case EHScope::Catch:
case EHScope::Cleanup:
case EHScope::Filter:
@@ -669,11 +734,6 @@
CGBuilderTy::InsertPoint savedIP = Builder.saveAndClearIP();
auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, CurEHLocation);
- const EHPersonality &personality = EHPersonality::get(*this);
-
- if (!CurFn->hasPersonalityFn())
- CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, personality));
-
// Create and configure the landing pad.
llvm::BasicBlock *lpad = createBasicBlock("lpad");
EmitBlock(lpad);
@@ -728,6 +788,9 @@
case EHScope::Catch:
break;
+
+ case EHScope::CatchEnd:
+ llvm_unreachable("CatchEnd unnecessary for Itanium!");
}
EHCatchScope &catchScope = cast<EHCatchScope>(*I);
@@ -792,10 +855,63 @@
return lpad;
}
+static llvm::BasicBlock *emitMSVCCatchDispatchBlock(CodeGenFunction &CGF,
+ EHCatchScope &CatchScope) {
+ llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
+ assert(DispatchBlock);
+
+ CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
+ CGF.EmitBlockAfterUses(DispatchBlock);
+
+ // Figure out the next block.
+ llvm::BasicBlock *NextBlock = nullptr;
+
+ // Test against each of the exception types we claim to catch.
+ for (unsigned I = 0, E = CatchScope.getNumHandlers(); I < E; ++I) {
+ const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
+
+ llvm::Value *TypeValue = Handler.Type;
+ assert(TypeValue != nullptr || Handler.isCatchAll());
+ if (!TypeValue)
+ TypeValue = llvm::Constant::getNullValue(CGF.VoidPtrTy);
+
+ // If this is the last handler, we're at the end, and the next
+ // block is the block for the enclosing EH scope.
+ if (I + 1 == E) {
+ NextBlock = CGF.createBasicBlock("catchendblock");
+ CGBuilderTy(NextBlock).CreateCatchEndPad(
+ CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope()));
+ } else {
+ NextBlock = CGF.createBasicBlock("catch.dispatch");
+ }
+
+ if (EHPersonality::get(CGF).isMSVCXXPersonality()) {
+ CGF.Builder.CreateCatchPad(
+ CGF.VoidTy, Handler.Block, NextBlock,
+ {TypeValue, llvm::Constant::getNullValue(CGF.VoidPtrTy)});
+ } else {
+ CGF.Builder.CreateCatchPad(CGF.VoidTy, Handler.Block, NextBlock,
+ {TypeValue});
+ }
+
+ // Otherwise we need to emit and continue at that block.
+ CGF.EmitBlock(NextBlock);
+ }
+ CGF.Builder.restoreIP(SavedIP);
+
+ return NextBlock;
+}
+
/// Emit the structure of the dispatch block for the given catch scope.
/// It is an invariant that the dispatch block already exists.
-static void emitCatchDispatchBlock(CodeGenFunction &CGF,
- EHCatchScope &catchScope) {
+/// If the catchblock instructions are used for EH dispatch, then the basic
+/// block holding the final catchendblock instruction is returned.
+static llvm::BasicBlock *emitCatchDispatchBlock(CodeGenFunction &CGF,
+ EHCatchScope &catchScope) {
+ if (CGF.CGM.getCodeGenOpts().NewMSEH &&
+ EHPersonality::get(CGF).isMSVCPersonality())
+ return emitMSVCCatchDispatchBlock(CGF, catchScope);
+
llvm::BasicBlock *dispatchBlock = catchScope.getCachedEHDispatchBlock();
assert(dispatchBlock);
@@ -804,7 +920,7 @@
if (catchScope.getNumHandlers() == 1 &&
catchScope.getHandler(0).isCatchAll()) {
assert(dispatchBlock == catchScope.getHandler(0).Block);
- return;
+ return nullptr;
}
CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveIP();
@@ -860,11 +976,12 @@
// If the next handler is a catch-all, we're completely done.
if (nextIsEnd) {
CGF.Builder.restoreIP(savedIP);
- return;
+ return nullptr;
}
// Otherwise we need to emit and continue at that block.
CGF.EmitBlock(nextBlock);
}
+ return nullptr;
}
void CodeGenFunction::popCatchScope() {
@@ -887,7 +1004,7 @@
}
// Emit the structure of the EH dispatch for this catch.
- emitCatchDispatchBlock(*this, CatchScope);
+ llvm::BasicBlock *CatchEndBlockBB = emitCatchDispatchBlock(*this, CatchScope);
// Copy the handler blocks off before we pop the EH stack. Emitting
// the handlers might scribble on this memory.
@@ -911,6 +1028,9 @@
doImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
isa<CXXConstructorDecl>(CurCodeDecl);
+ if (CatchEndBlockBB)
+ EHStack.pushCatchEnd(CatchEndBlockBB);
+
// Perversely, we emit the handlers backwards precisely because we
// want them to appear in source order. In all of these cases, the
// catch block will have exactly one predecessor, which will be a
@@ -963,6 +1083,8 @@
EmitBlock(ContBB);
incrementProfileCounter(&S);
+ if (CatchEndBlockBB)
+ EHStack.popCatchEnd();
}
namespace {
@@ -1200,13 +1322,18 @@
// end of the function by FinishFunction.
TerminateHandler = createBasicBlock("terminate.handler");
Builder.SetInsertPoint(TerminateHandler);
- llvm::Value *Exn = 0;
- if (getLangOpts().CPlusPlus)
- Exn = getExceptionFromSlot();
- llvm::CallInst *terminateCall =
- CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
- terminateCall->setDoesNotReturn();
- Builder.CreateUnreachable();
+ if (CGM.getCodeGenOpts().NewMSEH &&
+ EHPersonality::get(*this).isMSVCPersonality()) {
+ Builder.CreateTerminatePad(/*UnwindBB=*/nullptr, CGM.getTerminateFn());
+ } else {
+ llvm::Value *Exn = 0;
+ if (getLangOpts().CPlusPlus)
+ Exn = getExceptionFromSlot();
+ llvm::CallInst *terminateCall =
+ CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
+ terminateCall->setDoesNotReturn();
+ Builder.CreateUnreachable();
+ }
// Restore the saved insertion state.
Builder.restoreIP(SavedIP);
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index ec3c75c..9bf4161 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -826,15 +826,11 @@
// can't do this on functions that can be overwritten.
if (F->mayBeOverridden()) return;
- for (llvm::Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI)
- for (llvm::BasicBlock::iterator
- BI = FI->begin(), BE = FI->end(); BI != BE; ++BI)
- if (llvm::CallInst *Call = dyn_cast<llvm::CallInst>(&*BI)) {
- if (!Call->doesNotThrow())
- return;
- } else if (isa<llvm::ResumeInst>(&*BI)) {
+ for (llvm::BasicBlock &BB : *F)
+ for (llvm::Instruction &I : BB)
+ if (I.mayThrow())
return;
- }
+
F->setDoesNotThrow();
}
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index b7d6bbd..c463350 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -665,6 +665,7 @@
llvm::BasicBlock *getEHResumeBlock(bool isCleanup);
llvm::BasicBlock *getEHDispatchBlock(EHScopeStack::stable_iterator scope);
+ llvm::BasicBlock *getMSVCDispatchBlock(EHScopeStack::stable_iterator scope);
/// An object to manage conditionally-evaluated expressions.
class ConditionalEvaluation {
diff --git a/clang/lib/CodeGen/EHScopeStack.h b/clang/lib/CodeGen/EHScopeStack.h
index dc7a6c6..8cad5b6 100644
--- a/clang/lib/CodeGen/EHScopeStack.h
+++ b/clang/lib/CodeGen/EHScopeStack.h
@@ -329,6 +329,10 @@
/// Pops a terminate handler off the stack.
void popTerminate();
+ void pushCatchEnd(llvm::BasicBlock *CatchEndBlockBB);
+
+ void popCatchEnd();
+
// Returns true iff the current scope is either empty or contains only
// lifetime markers, i.e. no real cleanup code
bool containsOnlyLifetimeMarkers(stable_iterator Old) const;
diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index 613d29a..3084446 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -855,8 +855,14 @@
struct CallEndCatchMSVC : EHScopeStack::Cleanup {
CallEndCatchMSVC() {}
void Emit(CodeGenFunction &CGF, Flags flags) override {
- CGF.EmitNounwindRuntimeCall(
- CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
+ if (CGF.CGM.getCodeGenOpts().NewMSEH) {
+ llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest");
+ CGF.Builder.CreateCatchRet(BB);
+ CGF.EmitBlock(BB);
+ } else {
+ CGF.EmitNounwindRuntimeCall(
+ CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
+ }
}
};
}
@@ -866,24 +872,36 @@
// In the MS ABI, the runtime handles the copy, and the catch handler is
// responsible for destruction.
VarDecl *CatchParam = S->getExceptionDecl();
- llvm::Value *Exn = CGF.getExceptionFromSlot();
- llvm::Function *BeginCatch =
- CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
-
+ llvm::Value *Exn = nullptr;
+ llvm::Function *BeginCatch = nullptr;
+ bool NewEH = CGF.CGM.getCodeGenOpts().NewMSEH;
+ if (!NewEH) {
+ Exn = CGF.getExceptionFromSlot();
+ BeginCatch = CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
+ }
// If this is a catch-all or the catch parameter is unnamed, we don't need to
// emit an alloca to the object.
if (!CatchParam || !CatchParam->getDeclName()) {
- llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
- CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
+ if (!NewEH) {
+ llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
+ CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
+ }
CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup);
return;
}
CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
- llvm::Value *ParamAddr =
- CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
- llvm::Value *Args[2] = {Exn, ParamAddr};
- CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
+ if (!NewEH) {
+ llvm::Value *ParamAddr =
+ CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
+ llvm::Value *Args[2] = {Exn, ParamAddr};
+ CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
+ } else {
+ llvm::BasicBlock *CatchPadBB =
+ CGF.Builder.GetInsertBlock()->getSinglePredecessor();
+ auto *CPI = cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
+ CPI->setArgOperand(1, var.getObjectAddress(CGF));
+ }
CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup);
CGF.EmitAutoVarCleanups(var);
}