mattd created this revision.
mattd added reviewers: erik.pilkington, rsmith.
The flag: `-Wc++17-compat-mangling` was not emitting a warning diagnostic in
all cases, specifically if a function has parameters that happen to have
function pointers that have noexecept parameters. For example:
void fn(void (*)(void (*)() noexcept)){}
That example will produce different symbol names between c++17 and earlier
dialects. I believe that clang should be emitting the compatibility warning in
this case. This patch modifies the existing logic to recursively check the
parameters of a function and warn if they too are noexcept.
This fixes PR39656.
https://reviews.llvm.org/D55039
Files:
lib/Sema/SemaDecl.cpp
test/CXX/except/except.spec/p2-places.cpp
test/SemaCXX/cxx1z-noexcept-function-type.cpp
Index: test/SemaCXX/cxx1z-noexcept-function-type.cpp
===================================================================
--- test/SemaCXX/cxx1z-noexcept-function-type.cpp
+++ test/SemaCXX/cxx1z-noexcept-function-type.cpp
@@ -83,14 +83,16 @@
auto f5() -> void (*)() throw();
auto f6() -> void (&)() throw();
auto f7() -> void (X::*)() throw();
+ void f8(int, void (*)(int, void (*)() noexcept));
#if __cplusplus <= 201402L && !defined(NO_COMPAT_MANGLING)
- // expected-warning@-8 {{mangled name of 'f1' will change in C++17 due to
non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f2' will change in C++17 due to
non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f3' will change in C++17 due to
non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f4' will change in C++17 due to
non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f5' will change in C++17 due to
non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f6' will change in C++17 due to
non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f7' will change in C++17 due to
non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f1' will change in C++17 due to
non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f2' will change in C++17 due to
non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f3' will change in C++17 due to
non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f4' will change in C++17 due to
non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f5' will change in C++17 due to
non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f6' will change in C++17 due to
non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f7' will change in C++17 due to
non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f8' will change in C++17 due to
non-throwing exception specification in function signature}}
#endif
// An instantiation-dependent exception specification needs to be mangled in
Index: test/CXX/except/except.spec/p2-places.cpp
===================================================================
--- test/CXX/except/except.spec/p2-places.cpp
+++ test/CXX/except/except.spec/p2-places.cpp
@@ -55,7 +55,7 @@
void (*h())() noexcept(false);
- void (*i() noexcept(false))(void (*)() noexcept(true)) noexcept(false);
+ void (*i() noexcept(false))(void (*)() noexcept(true)) noexcept(false); //
expected-warning {{mangled name of 'i' will change in C++17 due to non-throwing
exception specification in function signature}}
void (**k)(void pfa() noexcept(false)); // no-error
Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -10209,7 +10209,7 @@
// most cases, and exception specifications are not permitted in most other
// contexts where they could make it into a mangling.)
if (!getLangOpts().CPlusPlus17 && !NewFD->getPrimaryTemplate()) {
- auto HasNoexcept = [&](QualType T) -> bool {
+ std::function<bool(QualType)> HasNoexcept = [&](QualType T) -> bool {
// Strip off declarator chunks that could be between us and a function
// type. We don't need to look far, exception specifications are very
// restricted prior to C++17.
@@ -10219,9 +10219,12 @@
T = T->getPointeeType();
else if (auto *MPT = T->getAs<MemberPointerType>())
T = MPT->getPointeeType();
- if (auto *FPT = T->getAs<FunctionProtoType>())
- if (FPT->isNothrow())
+ if (auto *FPT = T->getAs<FunctionProtoType>()) {
+ if (FPT->isNothrow() ||
+ llvm::any_of(FPT->param_types(),
+ [&](QualType Q) { return HasNoexcept(Q); }))
return true;
+ }
return false;
};
Index: test/SemaCXX/cxx1z-noexcept-function-type.cpp
===================================================================
--- test/SemaCXX/cxx1z-noexcept-function-type.cpp
+++ test/SemaCXX/cxx1z-noexcept-function-type.cpp
@@ -83,14 +83,16 @@
auto f5() -> void (*)() throw();
auto f6() -> void (&)() throw();
auto f7() -> void (X::*)() throw();
+ void f8(int, void (*)(int, void (*)() noexcept));
#if __cplusplus <= 201402L && !defined(NO_COMPAT_MANGLING)
- // expected-warning@-8 {{mangled name of 'f1' will change in C++17 due to non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f2' will change in C++17 due to non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f3' will change in C++17 due to non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f4' will change in C++17 due to non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f5' will change in C++17 due to non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f6' will change in C++17 due to non-throwing exception specification in function signature}}
- // expected-warning@-8 {{mangled name of 'f7' will change in C++17 due to non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f1' will change in C++17 due to non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f2' will change in C++17 due to non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f3' will change in C++17 due to non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f4' will change in C++17 due to non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f5' will change in C++17 due to non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f6' will change in C++17 due to non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f7' will change in C++17 due to non-throwing exception specification in function signature}}
+ // expected-warning@-9 {{mangled name of 'f8' will change in C++17 due to non-throwing exception specification in function signature}}
#endif
// An instantiation-dependent exception specification needs to be mangled in
Index: test/CXX/except/except.spec/p2-places.cpp
===================================================================
--- test/CXX/except/except.spec/p2-places.cpp
+++ test/CXX/except/except.spec/p2-places.cpp
@@ -55,7 +55,7 @@
void (*h())() noexcept(false);
- void (*i() noexcept(false))(void (*)() noexcept(true)) noexcept(false);
+ void (*i() noexcept(false))(void (*)() noexcept(true)) noexcept(false); // expected-warning {{mangled name of 'i' will change in C++17 due to non-throwing exception specification in function signature}}
void (**k)(void pfa() noexcept(false)); // no-error
Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -10209,7 +10209,7 @@
// most cases, and exception specifications are not permitted in most other
// contexts where they could make it into a mangling.)
if (!getLangOpts().CPlusPlus17 && !NewFD->getPrimaryTemplate()) {
- auto HasNoexcept = [&](QualType T) -> bool {
+ std::function<bool(QualType)> HasNoexcept = [&](QualType T) -> bool {
// Strip off declarator chunks that could be between us and a function
// type. We don't need to look far, exception specifications are very
// restricted prior to C++17.
@@ -10219,9 +10219,12 @@
T = T->getPointeeType();
else if (auto *MPT = T->getAs<MemberPointerType>())
T = MPT->getPointeeType();
- if (auto *FPT = T->getAs<FunctionProtoType>())
- if (FPT->isNothrow())
+ if (auto *FPT = T->getAs<FunctionProtoType>()) {
+ if (FPT->isNothrow() ||
+ llvm::any_of(FPT->param_types(),
+ [&](QualType Q) { return HasNoexcept(Q); }))
return true;
+ }
return false;
};
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