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llvm-project/clang/test/CodeGenCXX/stack-reuse-exceptions.cpp

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[CodeGen] Emit lifetime.ends in both EH and non-EH blocks Before this, we'd only emit lifetime.ends for these temps in non-exceptional paths. This potentially made our stack larger than it needed to be for any code that follows an EH cleanup. e.g. in ``` struct Foo { char cs[32]; }; void escape(void *); struct Bar { ~Bar() { char cs[64]; escape(cs); } }; Foo getFoo(); void baz() { Bar b; getFoo(); } ``` baz() would require 96 bytes of stack, since the temporary from getFoo() only had a lifetime.end on the non-exceptional path. This also makes us keep hold of the Value* returned by EmitLifetimeStart, so we don't have to remake it later. llvm-svn: 326988
2018-03-08 13:32:30 +08:00
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu %s -o - -emit-llvm -O1 \
Revert r361811: 'Re-commit r357452 (take 2): "SimplifyCFG SinkCommonCodeFromPredecessors ...' We have observed some failures with internal builds with this revision. - Performance regressions: - llvm's SingleSource/Misc evalloop shows performance regressions (although these may be red herrings). - Benchmarks for Abseil's SwissTable. - Correctness: - Failures for particular libicu tests when building the Google AppEngine SDK (for PHP). hwennborg has already been notified, and is aware of reproducer failures. llvm-svn: 363220
2019-06-13 10:04:45 +08:00
// RUN: -fexceptions -fcxx-exceptions | FileCheck %s
[CodeGen] Emit lifetime.ends in both EH and non-EH blocks Before this, we'd only emit lifetime.ends for these temps in non-exceptional paths. This potentially made our stack larger than it needed to be for any code that follows an EH cleanup. e.g. in ``` struct Foo { char cs[32]; }; void escape(void *); struct Bar { ~Bar() { char cs[64]; escape(cs); } }; Foo getFoo(); void baz() { Bar b; getFoo(); } ``` baz() would require 96 bytes of stack, since the temporary from getFoo() only had a lifetime.end on the non-exceptional path. This also makes us keep hold of the Value* returned by EmitLifetimeStart, so we don't have to remake it later. llvm-svn: 326988
2018-03-08 13:32:30 +08:00
//
// We should emit lifetime.ends for these temporaries in both the 'exception'
// and 'normal' paths in functions.
//
// -O1 is necessary to make lifetime markers appear.
struct Large {
int cs[32];
};
Large getLarge();
// Used to ensure we emit invokes.
struct NontrivialDtor {
int i;
~NontrivialDtor();
};
// CHECK-LABEL: define void @_Z33cleanupsAreEmittedWithoutTryCatchv
void cleanupsAreEmittedWithoutTryCatch() {
// CHECK: %[[CLEAN:[^ ]+]] = bitcast %struct.NontrivialDtor* %{{[^ ]+}} to i8*
// CHECK: call void @llvm.lifetime.start.p0i8({{[^,]+}}, i8* nonnull %[[CLEAN]])
// CHECK: %[[T1:[^ ]+]] = bitcast %struct.Large* %{{[^ ]+}} to i8*
// CHECK: call void @llvm.lifetime.start.p0i8({{[^,]+}}, i8* nonnull %[[T1]])
// CHECK-NEXT: invoke void @_Z8getLargev
// CHECK-NEXT: to label %[[CONT:[^ ]+]] unwind label %[[LPAD:[^ ]+]]
//
// CHECK: [[CONT]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T1]])
// CHECK: %[[T2:[^ ]+]] = bitcast %struct.Large* %{{[^ ]+}} to i8*
// CHECK: call void @llvm.lifetime.start.p0i8({{[^,]+}}, i8* nonnull %[[T2]])
// CHECK-NEXT: invoke void @_Z8getLargev
// CHECK-NEXT: to label %[[CONT2:[^ ]+]] unwind label %[[LPAD2:.+]]
//
// CHECK: [[CONT2]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T2]])
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[CLEAN]])
// CHECK: ret void
//
// CHECK: [[LPAD]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T1]])
// CHECK: br label %[[EHCLEANUP:.+]]
//
// CHECK: [[LPAD2]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T2]])
// CHECK: br label %[[EHCLEANUP]]
//
// CHECK: [[EHCLEANUP]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[CLEAN]])
NontrivialDtor clean;
getLarge();
getLarge();
}
// CHECK-LABEL: define void @_Z30cleanupsAreEmittedWithTryCatchv
void cleanupsAreEmittedWithTryCatch() {
// CHECK: %[[CLEAN:[^ ]+]] = bitcast %struct.NontrivialDtor* %{{[^ ]+}} to i8*
// CHECK: call void @llvm.lifetime.start.p0i8({{[^,]+}}, i8* nonnull %[[CLEAN]])
// CHECK: %[[T1:[^ ]+]] = bitcast %struct.Large* %{{[^ ]+}} to i8*
// CHECK: call void @llvm.lifetime.start.p0i8({{[^,]+}}, i8* nonnull %[[T1]])
// CHECK-NEXT: invoke void @_Z8getLargev
// CHECK-NEXT: to label %[[CONT:[^ ]+]] unwind label %[[LPAD:[^ ]+]]
//
// CHECK: [[CONT]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T1]])
// CHECK: %[[T2:[^ ]+]] = bitcast %struct.Large* %{{[^ ]+}} to i8*
// CHECK: call void @llvm.lifetime.start.p0i8({{[^,]+}}, i8* nonnull %[[T2]])
// CHECK-NEXT: invoke void @_Z8getLargev
// CHECK-NEXT: to label %[[CONT2:[^ ]+]] unwind label %[[LPAD2:.+]]
//
// CHECK: [[CONT2]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T2]])
// CHECK: br label %[[TRY_CONT:.+]]
//
// CHECK: [[LPAD]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T1]])
// CHECK: br label %[[CATCH:.+]]
//
// CHECK: [[LPAD2]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T2]])
// CHECK: br label %[[CATCH]]
//
// CHECK: [[CATCH]]:
// CHECK-NOT: call void @llvm.lifetime
// CHECK: invoke void
// CHECK-NEXT: to label %[[TRY_CONT]] unwind label %[[OUTER_LPAD:.+]]
//
// CHECK: [[TRY_CONT]]:
// CHECK: %[[T_OUTER:[^ ]+]] = bitcast %struct.Large* %{{[^ ]+}} to i8*
// CHECK: call void @llvm.lifetime.start.p0i8({{[^,]+}}, i8* nonnull %[[T_OUTER]])
// CHECK-NEXT: invoke void @_Z8getLargev
// CHECK-NEXT: to label %[[OUTER_CONT:[^ ]+]] unwind label %[[OUTER_LPAD2:.+]]
//
// CHECK: [[OUTER_CONT]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T_OUTER]])
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[CLEAN]])
// CHECK: ret void
//
// CHECK: [[OUTER_LPAD]]:
// CHECK-NOT: call void @llvm.lifetime
// CHECK: br label %[[EHCLEANUP:.+]]
//
// CHECK: [[OUTER_LPAD2]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T_OUTER]])
// CHECK: br label %[[EHCLEANUP]]
//
// CHECK: [[EHCLEANUP]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[CLEAN]])
NontrivialDtor clean;
try {
getLarge();
getLarge();
} catch (...) {}
getLarge();
}
// CHECK-LABEL: define void @_Z39cleanupInTryHappensBeforeCleanupInCatchv
void cleanupInTryHappensBeforeCleanupInCatch() {
// CHECK: %[[T1:[^ ]+]] = bitcast %struct.Large* %{{[^ ]+}} to i8*
// CHECK: call void @llvm.lifetime.start.p0i8({{[^,]+}}, i8* nonnull %[[T1]])
// CHECK-NEXT: invoke void @_Z8getLargev
// CHECK-NEXT: to label %[[CONT:[^ ]+]] unwind label %[[LPAD:[^ ]+]]
//
// CHECK: [[CONT]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T1]])
// CHECK: br label %[[TRY_CONT]]
//
// CHECK: [[LPAD]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T1]])
// CHECK: br i1 {{[^,]+}}, label %[[CATCH_INT_MATCH:[^,]+]], label %[[CATCH_ALL:.+]]
//
// CHECK: [[CATCH_INT_MATCH]]:
// CHECK: %[[T2:[^ ]+]] = bitcast %struct.Large* %{{[^ ]+}} to i8*
// CHECK: call void @llvm.lifetime.start.p0i8({{[^,]+}}, i8* nonnull %[[T2]])
// CHECK-NEXT: invoke void @_Z8getLargev
// CHECK-NEXT: to label %[[CATCH_INT_CONT:[^ ]+]] unwind label %[[CATCH_INT_LPAD:[^ ]+]]
//
// CHECK: [[CATCH_INT_CONT]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T2]])
// CHECK: br label %[[TRY_CONT]]
//
// CHECK: [[TRY_CONT]]:
// CHECK: ret void
//
// CHECK: [[CATCH_ALL]]:
// CHECK: %[[T3:[^ ]+]] = bitcast %struct.Large* %{{[^ ]+}} to i8*
// CHECK: call void @llvm.lifetime.start.p0i8({{[^,]+}}, i8* nonnull %[[T3]])
// CHECK-NEXT: invoke void @_Z8getLargev
// CHECK-NEXT: to label %[[CATCH_ALL_CONT:[^ ]+]] unwind label %[[CATCH_ALL_LPAD:[^ ]+]]
//
// CHECK: [[CATCH_ALL_CONT]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T3]])
// CHECK: br label %[[TRY_CONT]]
//
// CHECK: [[CATCH_ALL_LPAD]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T3]])
//
// CHECK: [[CATCH_INT_LPAD]]:
// CHECK: call void @llvm.lifetime.end.p0i8({{[^,]+}}, i8* nonnull %[[T2]])
// CHECK-NOT: call void @llvm.lifetime
try {
getLarge();
} catch (const int &) {
getLarge();
} catch (...) {
getLarge();
}
}
// FIXME: We don't currently emit lifetime markers for aggregate by-value
// temporaries (e.g. given a function `Large combine(Large, Large);`
// combine(getLarge(), getLarge()) "leaks" two `Large`s). We probably should. We
// also don't emit markers for things like:
//
// {
// Large L = getLarge();
// combine(L, L);
// }
//
// Though this arguably isn't as bad, since we pass a pointer to `L` as one of
// the two args.