ahatanak created this revision.
ahatanak added reviewers: rnk, rjmccall.
ahatanak added a subscriber: cfe-commits.
This patch fixes a bug in CodeGen where lifetime.end intrinsics were not being
inserted after destructor calls in landing pad blocks, which prevented
StackColoring from merging stack slots for allocas because it couldn't tell
their lifetime ranges were disjoint.
This patch changes the code in CodeGenFunction::EmitAutoVarCleanup to pass
NormalAndEHCleanup instead of NormalCleanup to EHScopeStack::pushCleanup so
that CallLifetimeEnd runs the cleanup code when a scope is exited using
exceptional control flow too. I initially considered adding code to
DestroyObject::Emit to emit lifetime.end after the destructor call, but letting
CallLifetimeEnd emit lifetime.end seemed like a better approach.
This is the link to the discussion on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-March/096233.html
http://reviews.llvm.org/D18196
Files:
lib/CodeGen/CGCleanup.cpp
lib/CodeGen/CGDecl.cpp
lib/CodeGen/EHScopeStack.h
test/CodeGenCXX/destructors.cpp
Index: test/CodeGenCXX/destructors.cpp
===================================================================
--- test/CodeGenCXX/destructors.cpp
+++ test/CodeGenCXX/destructors.cpp
@@ -4,6 +4,8 @@
// RUN: FileCheck --check-prefix=CHECK3 --input-file=%t %s
// RUN: FileCheck --check-prefix=CHECK4 --input-file=%t %s
// RUN: FileCheck --check-prefix=CHECK5 --input-file=%t %s
+// RUN: %clang_cc1 %s -triple x86_64-apple-darwin10 -emit-llvm -o - -fcxx-exceptions -fexceptions -O1 -disable-llvm-optzns -std=c++11 > %t2
+// RUN: FileCheck --check-prefix=CHECK6 --input-file=%t2 %s
struct A {
int a;
@@ -428,3 +430,64 @@
return true;
}
}
+
+#if __cplusplus >= 201103L
+namespace test11 {
+
+// Check that lifetime.end is emitted in the landing pad.
+
+// CHECK6-LABEL: define void @_ZN6test1115testLifetimeEndEi(
+// CHECK6: entry:
+// CHECK6: [[T1:%[a-z0-9]+]] = alloca %"struct.test11::S1"
+// CHECK6: [[T2:%[a-z0-9]+]] = alloca %"struct.test11::S1"
+// CHECK6: [[T3:%[a-z0-9]+]] = alloca %"struct.test11::S1"
+
+// CHECK6: {{^}}invoke.cont
+// CHECK6: call void @_ZN6test112S1D1Ev(%"struct.test11::S1"* [[T1]])
+// CHECK6: [[BC1:%[a-z0-9]+]] = bitcast %"struct.test11::S1"* [[T1]] to i8*
+// CHECK6: call void @llvm.lifetime.end(i64 32, i8* [[BC1]])
+// CHECK6: {{^}}lpad
+// CHECK6: call void @_ZN6test112S1D1Ev(%"struct.test11::S1"* [[T1]])
+// CHECK6: [[BC2:%[a-z0-9]+]] = bitcast %"struct.test11::S1"* [[T1]] to i8*
+// CHECK6: call void @llvm.lifetime.end(i64 32, i8* [[BC2]])
+
+// CHECK6: {{^}}invoke.cont
+// CHECK6: call void @_ZN6test112S1D1Ev(%"struct.test11::S1"* [[T2]])
+// CHECK6: [[BC3:%[a-z0-9]+]] = bitcast %"struct.test11::S1"* [[T2]] to i8*
+// CHECK6: call void @llvm.lifetime.end(i64 32, i8* [[BC3]])
+// CHECK6: {{^}}lpad
+// CHECK6: call void @_ZN6test112S1D1Ev(%"struct.test11::S1"* [[T2]])
+// CHECK6: [[BC4:%[a-z0-9]+]] = bitcast %"struct.test11::S1"* [[T2]] to i8*
+// CHECK6: call void @llvm.lifetime.end(i64 32, i8* [[BC4]])
+
+// CHECK6: {{^}}invoke.cont
+// CHECK6: call void @_ZN6test112S1D1Ev(%"struct.test11::S1"* [[T3]])
+// CHECK6: [[BC5:%[a-z0-9]+]] = bitcast %"struct.test11::S1"* [[T3]] to i8*
+// CHECK6: call void @llvm.lifetime.end(i64 32, i8* [[BC5]])
+// CHECK6: {{^}}lpad
+// CHECK6: call void @_ZN6test112S1D1Ev(%"struct.test11::S1"* [[T3]])
+// CHECK6: [[BC6:%[a-z0-9]+]] = bitcast %"struct.test11::S1"* [[T3]] to i8*
+// CHECK6: call void @llvm.lifetime.end(i64 32, i8* [[BC6]])
+
+ struct S1 {
+ ~S1();
+ int a[8];
+ };
+
+ void func1(S1 &) noexcept(false);
+
+ void testLifetimeEnd(int n) {
+ if (n < 10) {
+ S1 t1;
+ func1(t1);
+ } else if (n < 100) {
+ S1 t2;
+ func1(t2);
+ } else if (n < 1000) {
+ S1 t3;
+ func1(t3);
+ }
+ }
+
+}
+#endif
Index: lib/CodeGen/EHScopeStack.h
===================================================================
--- lib/CodeGen/EHScopeStack.h
+++ lib/CodeGen/EHScopeStack.h
@@ -341,9 +341,7 @@
/// Determines whether the exception-scopes stack is empty.
bool empty() const { return StartOfData == EndOfBuffer; }
- bool requiresLandingPad() const {
- return InnermostEHScope != stable_end();
- }
+ bool requiresLandingPad() const;
/// Determines whether there are any normal cleanups on the stack.
bool hasNormalCleanups() const {
Index: lib/CodeGen/CGDecl.cpp
===================================================================
--- lib/CodeGen/CGDecl.cpp
+++ lib/CodeGen/CGDecl.cpp
@@ -1388,7 +1388,7 @@
// Make sure we call @llvm.lifetime.end. This needs to happen
// *last*, so the cleanup needs to be pushed *first*.
if (emission.useLifetimeMarkers()) {
- EHStack.pushCleanup<CallLifetimeEnd>(NormalCleanup,
+ EHStack.pushCleanup<CallLifetimeEnd>(NormalAndEHCleanup,
emission.getAllocatedAddress(),
emission.getSizeForLifetimeMarkers());
EHCleanupScope &cleanup = cast<EHCleanupScope>(*EHStack.begin());
Index: lib/CodeGen/CGCleanup.cpp
===================================================================
--- lib/CodeGen/CGCleanup.cpp
+++ lib/CodeGen/CGCleanup.cpp
@@ -157,6 +157,20 @@
return true;
}
+bool EHScopeStack::requiresLandingPad() const {
+ for (stable_iterator si = getInnermostEHScope(); si != stable_end(); ) {
+ // Skip lifetime markers.
+ if (auto *cleanup = dyn_cast<EHCleanupScope>(&*find(si)))
+ if (cleanup->isLifetimeMarker()) {
+ si = cleanup->getEnclosingEHScope();
+ continue;
+ }
+ return true;
+ }
+
+ return false;
+}
+
EHScopeStack::stable_iterator
EHScopeStack::getInnermostActiveNormalCleanup() const {
for (stable_iterator si = getInnermostNormalCleanup(), se = stable_end();
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