MaskRay updated this revision to Diff 557798.
MaskRay retitled this revision from "[ItaniumCXXABI] Make __cxa_end_catch calls
unconditionally nounwind" to "[ItaniumCXXABI] Add
-fassume-nothrow-exception-dtor to assume that an exception object' destructor
is nothrow".
MaskRay edited the summary of this revision.
MaskRay added a comment.
This revision is now accepted and ready to land.
Switch to opt-in
Add -fassume-nothrow-exception-dtor
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D108905/new/
https://reviews.llvm.org/D108905
Files:
clang/include/clang/Basic/CodeGenOptions.def
clang/include/clang/Driver/Options.td
clang/lib/CodeGen/ItaniumCXXABI.cpp
clang/lib/Driver/ToolChains/Clang.cpp
clang/test/CodeGenCXX/eh.cpp
clang/test/CodeGenCXX/exceptions.cpp
clang/test/CodeGenCoroutines/coro-cleanup.cpp
clang/test/Driver/clang-exception-flags.cpp
Index: clang/test/Driver/clang-exception-flags.cpp
===================================================================
--- clang/test/Driver/clang-exception-flags.cpp
+++ clang/test/Driver/clang-exception-flags.cpp
@@ -27,3 +27,6 @@
// RUN: %clang -### -target x86_64-scei-ps4 %s 2>&1 | FileCheck %s -check-prefix=PS-OFF
// RUN: %clang -### -target x86_64-sie-ps5 %s 2>&1 | FileCheck %s -check-prefix=PS-OFF
// PS-OFF-NOT: "-cc1" {{.*}} "-f{{(cxx-)?}}exceptions"
+
+// RUN: %clang -### -fexceptions -fno-assume-nothrow-exception-dtor -fassume-nothrow-exception-dtor %s 2>&1 | FileCheck %s --check-prefix=NOTHROW-DTOR
+// NOTHROW-DTOR: "-cc1"{{.*}} "-fcxx-exceptions" "-fassume-nothrow-exception-dtor"
Index: clang/test/CodeGenCoroutines/coro-cleanup.cpp
===================================================================
--- clang/test/CodeGenCoroutines/coro-cleanup.cpp
+++ clang/test/CodeGenCoroutines/coro-cleanup.cpp
@@ -1,5 +1,6 @@
// Verify that coroutine promise and allocated memory are freed up on exception.
-// RUN: %clang_cc1 -std=c++20 -triple=x86_64-unknown-linux-gnu -emit-llvm -o - %s -fexceptions -fcxx-exceptions -disable-llvm-passes | FileCheck %s
+// RUN: %clang_cc1 -std=c++20 -triple=x86_64-unknown-linux-gnu -emit-llvm -o - %s -fexceptions -fcxx-exceptions -disable-llvm-passes | FileCheck %s --check-prefixes=CHECK,THROWEND
+// RUN: %clang_cc1 -std=c++20 -triple=x86_64-unknown-linux-gnu -emit-llvm -o - %s -fexceptions -fcxx-exceptions -fassume-nothrow-exception-dtor -disable-llvm-passes | FileCheck %s --check-prefixes=CHECK,NOTHROWEND
namespace std {
template <typename... T> struct coroutine_traits;
@@ -49,7 +50,9 @@
// CHECK: [[DeallocPad]]:
// CHECK-NEXT: landingpad
// CHECK-NEXT: cleanup
- // CHECK: br label %[[Dealloc:.+]]
+ // THROWEND: br label %[[Dealloc:.+]]
+ // NOTHROWEND: icmp ne ptr %[[#]], null
+ // NOTHROWEND-NEXT: br i1 %[[#]], label %[[Dealloc:.+]], label
Cleanup cleanup;
may_throw();
@@ -64,17 +67,18 @@
// CHECK-NEXT: catch ptr null
// CHECK: call void @_ZN7CleanupD1Ev(
// CHECK: br label %[[Catch:.+]]
-
// CHECK: [[Catch]]:
// CHECK: call ptr @__cxa_begin_catch(
// CHECK: call void @_ZNSt16coroutine_traitsIJvEE12promise_type19unhandled_exceptionEv(
- // CHECK: invoke void @__cxa_end_catch()
- // CHECK-NEXT: to label %[[Cont:.+]] unwind
+ // THROWEND: invoke void @__cxa_end_catch()
+ // THROWEND-NEXT: to label %[[Cont:.+]] unwind
+ // NOTHROWEND: call void @__cxa_end_catch()
+ // NOTHROWEND-NEXT: br label %[[Cont2:.+]]
- // CHECK: [[Cont]]:
- // CHECK-NEXT: br label %[[Cont2:.+]]
- // CHECK: [[Cont2]]:
- // CHECK-NEXT: br label %[[Cleanup:.+]]
+ // THROWEND: [[Cont]]:
+ // THROWEND-NEXT: br label %[[Cont2:.+]]
+ // CHECK: [[Cont2]]:
+ // CHECK-NEXT: br label %[[Cleanup:.+]]
// CHECK: [[Cleanup]]:
// CHECK: call void @_ZNSt16coroutine_traitsIJvEE12promise_typeD1Ev(
@@ -82,8 +86,8 @@
// CHECK: call void @_ZdlPv(ptr noundef %[[Mem0]]
// CHECK: [[Dealloc]]:
- // CHECK: %[[Mem:.+]] = call ptr @llvm.coro.free(
- // CHECK: call void @_ZdlPv(ptr noundef %[[Mem]])
+ // THROWEND: %[[Mem:.+]] = call ptr @llvm.coro.free(
+ // THROWEND: call void @_ZdlPv(ptr noundef %[[Mem]])
co_return;
}
Index: clang/test/CodeGenCXX/exceptions.cpp
===================================================================
--- clang/test/CodeGenCXX/exceptions.cpp
+++ clang/test/CodeGenCXX/exceptions.cpp
@@ -1,5 +1,6 @@
// RUN: %clang_cc1 -no-enable-noundef-analysis %s -triple=x86_64-linux-gnu -emit-llvm -std=c++98 -o - -fcxx-exceptions -fexceptions | FileCheck -check-prefix=CHECK -check-prefix=CHECK98 %s
-// RUN: %clang_cc1 -no-enable-noundef-analysis %s -triple=x86_64-linux-gnu -emit-llvm -std=c++11 -o - -fcxx-exceptions -fexceptions | FileCheck -check-prefix=CHECK -check-prefix=CHECK11 %s
+// RUN: %clang_cc1 -no-enable-noundef-analysis %s -triple=x86_64-linux-gnu -emit-llvm -std=c++11 -o - -fcxx-exceptions -fexceptions | FileCheck --check-prefixes=CHECK,CHECK11,THROWEND11 %s
+// RUN: %clang_cc1 -no-enable-noundef-analysis %s -triple=x86_64-linux-gnu -emit-llvm -std=c++11 -o - -fcxx-exceptions -fexceptions -fassume-nothrow-exception-dtor | FileCheck --check-prefixes=CHECK,CHECK11,NOTHROWEND11 %s
// CHECK: %[[STRUCT_TEST13_A:.*]] = type { i32, i32 }
@@ -479,11 +480,16 @@
// CHECK98: call void @__cxa_end_catch()
// CHECK98-NEXT: br label
- // CHECK11: invoke void @__cxa_end_catch()
- // CHECK11-NEXT: to label
+ // THROWEND11: invoke void @__cxa_end_catch()
+ // THROWEND11-NEXT: to label %invoke.cont[[#]] unwind label %terminate.lpad
+ // NOTHROWEND11: call void @__cxa_end_catch()
+ // NOTHROWEND11-NEXT: br label
// CHECK: invoke void @__cxa_rethrow()
// CHECK: unreachable
+
+ // THROWEND11: terminate.lpad:
+ // THROWEND11: call void @__clang_call_terminate(
}
// Ensure that an exception in a constructor destroys
Index: clang/test/CodeGenCXX/eh.cpp
===================================================================
--- clang/test/CodeGenCXX/eh.cpp
+++ clang/test/CodeGenCXX/eh.cpp
@@ -1,5 +1,6 @@
-// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -triple x86_64-apple-macosx10.13.99 -std=c++11 -emit-llvm -o - %s | FileCheck --check-prefix=CHECK --check-prefix=UNALIGNED %s
-// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -triple x86_64-apple-macosx10.14 -std=c++11 -emit-llvm -o - %s | FileCheck --check-prefix=CHECK --check-prefix=ALIGNED %s
+// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -triple x86_64-apple-macosx10.13.99 -std=c++11 -emit-llvm -o - %s | FileCheck --check-prefixes=CHECK,UNALIGNED,THROWEND %s
+// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -triple x86_64-apple-macosx10.14 -std=c++11 -emit-llvm -o - %s | FileCheck --check-prefixes=CHECK,ALIGNED,THROWEND %s
+// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -triple x86_64-apple-macosx10.14 -std=c++11 -emit-llvm -o - %s -fassume-nothrow-exception-dtor | FileCheck --check-prefixes=CHECK,ALIGNED,NOTHROWEND %s
struct test1_D {
double d;
@@ -218,13 +219,16 @@
} catch (B a) {
// CHECK: call ptr @__cxa_begin_catch
// CHECK-NEXT: call void @llvm.memcpy
- // CHECK-NEXT: invoke void @__cxa_end_catch()
+ // THROWEND-NEXT: invoke void @__cxa_end_catch()
+ // NOTHROWEND-NEXT: call void @__cxa_end_catch() [[NUW]]
} catch (...) {
// CHECK: call ptr @__cxa_begin_catch
- // CHECK-NEXT: invoke void @__cxa_end_catch()
+ // THROWEND-NEXT: invoke void @__cxa_end_catch()
+ // NOTHROWEND-NEXT: call void @__cxa_end_catch() [[NUW]]
}
- // CHECK: call void @_ZN6test101AD1Ev(
+ // THROWEND: call void @_ZN6test101AD1Ev(
+ // NOTHROWEND-NOT: call void @_ZN6test101AD1Ev(
}
}
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -385,6 +385,9 @@
// So we do not set EH to false.
Args.AddLastArg(CmdArgs, options::OPT_fignore_exceptions);
+ Args.addOptInFlag(CmdArgs, options::OPT_fassume_nothrow_exception_dtor,
+ options::OPT_fno_assume_nothrow_exception_dtor);
+
if (EH)
CmdArgs.push_back("-fexceptions");
return EH;
Index: clang/lib/CodeGen/ItaniumCXXABI.cpp
===================================================================
--- clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -4508,7 +4508,9 @@
}
/// Emits a call to __cxa_begin_catch and enters a cleanup to call
-/// __cxa_end_catch.
+/// __cxa_end_catch. If -fassume-nothrow-exception-dtor is specified, we assume
+/// that the exception object's dtor is nothrow, therefore the __cxa_end_catch
+/// call can be marked as nounwind even if EndMightThrow is true.
///
/// \param EndMightThrow - true if __cxa_end_catch might throw
static llvm::Value *CallBeginCatch(CodeGenFunction &CGF,
@@ -4517,7 +4519,9 @@
llvm::CallInst *call =
CGF.EmitNounwindRuntimeCall(getBeginCatchFn(CGF.CGM), Exn);
- CGF.EHStack.pushCleanup<CallEndCatch>(NormalAndEHCleanup, EndMightThrow);
+ CGF.EHStack.pushCleanup<CallEndCatch>(
+ NormalAndEHCleanup,
+ EndMightThrow && !CGF.CGM.getCodeGenOpts().AssumeNothrowExceptionDtor);
return call;
}
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -1988,6 +1988,10 @@
Visibility<[ClangOption, CC1Option]>,
HelpText<"Enable support for ignoring exception handling constructs">,
MarshallingInfoFlag<LangOpts<"IgnoreExceptions">>;
+defm assume_nothrow_exception_dtor: BoolFOption<"assume-nothrow-exception-dtor",
+ CodeGenOpts<"AssumeNothrowExceptionDtor">, DefaultFalse,
+ PosFlag<SetTrue, [], [ClangOption, CC1Option], "Assume that exception objects' destructors are nothrow">,
+ NegFlag<SetFalse>>;
def fexcess_precision_EQ : Joined<["-"], "fexcess-precision=">, Group<f_Group>,
Visibility<[ClangOption, CLOption]>,
HelpText<"Allows control over excess precision on targets where native "
Index: clang/include/clang/Basic/CodeGenOptions.def
===================================================================
--- clang/include/clang/Basic/CodeGenOptions.def
+++ clang/include/clang/Basic/CodeGenOptions.def
@@ -37,6 +37,7 @@
CODEGENOPT(PreserveAsmComments, 1, 1) ///< -dA, -fno-preserve-as-comments.
CODEGENOPT(AssumeSaneOperatorNew , 1, 1) ///< implicit __attribute__((malloc)) operator new
CODEGENOPT(AssumeUniqueVTables , 1, 1) ///< Assume a class has only one vtable.
+CODEGENOPT(AssumeNothrowExceptionDtor , 1, 0) ///< Assume __cxa_end_catch is nothrow.
CODEGENOPT(Autolink , 1, 1) ///< -fno-autolink
CODEGENOPT(AutoImport , 1, 1) ///< -fno-auto-import
CODEGENOPT(ObjCAutoRefCountExceptions , 1, 0) ///< Whether ARC should be EH-safe.
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