Split -Wcast-function-type into a separate group #86131

AaronBallman · 2024-03-21T15:12:34Z

We want to add -Wcast-function-type to -Wextra (as done in 1de7e6c), but we do not want to add -Wcast-function-type-strict in at the same time (https://lab.llvm.org/buildbot/#/builders/57/builds/33601/steps/5/logs/stdio).

This moves the existing warning to a new group (-Wcast-function-type-mismatch), puts the new group under the existing -Wcast-function-type warning group, and adds -Wcast-function-type-mismatch to -Wextra.

We want to add -Wcast-function-type to -Wextra (as done in 1de7e6c), but we do not want to add -Wcast-function-type-strict in at the same time (https://lab.llvm.org/buildbot/#/builders/57/builds/33601/steps/5/logs/stdio). This moves the existing warning to a new group (-Wcast-function-type-mismatch), puts the new group under the existing -Wcast-function-type warning group, and adds -Wcast-function-type-mismatch to -Wextra

AaronBallman · 2024-03-21T15:12:45Z

CC @Abhinkop

llvmbot · 2024-03-21T15:13:08Z

@llvm/pr-subscribers-clang

Author: Aaron Ballman (AaronBallman)

Changes

We want to add -Wcast-function-type to -Wextra (as done in 1de7e6c), but we do not want to add -Wcast-function-type-strict in at the same time (https://lab.llvm.org/buildbot/#/builders/57/builds/33601/steps/5/logs/stdio).

This moves the existing warning to a new group (-Wcast-function-type-mismatch), puts the new group under the existing -Wcast-function-type warning group, and adds -Wcast-function-type-mismatch to -Wextra.

Full diff: https://github.com/llvm/llvm-project/pull/86131.diff

5 Files Affected:

(modified) clang/docs/ReleaseNotes.rst (+19-1)
(modified) clang/include/clang/Basic/DiagnosticGroups.td (+5-2)
(modified) clang/include/clang/Basic/DiagnosticSemaKinds.td (+1-1)
(modified) clang/test/Sema/warn-cast-function-type-strict.c (+6-6)
(modified) clang/test/SemaCXX/warn-cast-function-type-strict.cpp (+5-5)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index a9c55ef662a0b9..6939fb5b4bc953 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -196,7 +196,25 @@ Modified Compiler Flags
   ``-Wreturn-type``, and moved some of the diagnostics previously controlled by
   ``-Wreturn-type`` under this new flag. Fixes #GH72116.
 
-- Added ``-Wcast-function-type`` as a warning enabled by ``-Wextra``. #GH76872
+- Added ``-Wcast-function-type-mismatch`` under the ``-Wcast-function-type``
+  warning group. Moved the diagnostic previously controlled by
+  ``-Wcast-function-type`` to the new warning group and added
+  ``-Wcast-function-type-mismatch`` to ``-Wextra``. #GH76872
+
+  .. code-block:: c
+
+     int x(long);
+     typedef int (f2)(void*);
+     typedef int (f3)();
+
+     void func(void) {
+       // Diagnoses under -Wcast-function-type, -Wcast-function-type-mismatch,
+       // -Wcast-function-type-strict, -Wextra
+       f2 *b = (f2 *)x;
+       // Diagnoses under -Wcast-function-type, -Wcast-function-type-strict
+       f3 *c = (f3 *)x;
+     }
+
 
 Removed Compiler Flags
 -------------------------
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index bf03d4e8f67ee1..44035e2fd16f2e 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -573,7 +573,10 @@ def SelTypeCast : DiagGroup<"cast-of-sel-type">;
 def FunctionDefInObjCContainer : DiagGroup<"function-def-in-objc-container">;
 def BadFunctionCast : DiagGroup<"bad-function-cast">;
 def CastFunctionTypeStrict : DiagGroup<"cast-function-type-strict">;
-def CastFunctionType : DiagGroup<"cast-function-type", [CastFunctionTypeStrict]>;
+def CastFunctionTypeMismatch : DiagGroup<"cast-function-type-mismatch">;
+def CastFunctionType : DiagGroup<"cast-function-type",
+                                 [CastFunctionTypeStrict,
+                                  CastFunctionTypeMismatch]>;
 def ObjCPropertyImpl : DiagGroup<"objc-property-implementation">;
 def ObjCPropertyNoAttribute : DiagGroup<"objc-property-no-attribute">;
 def ObjCPropertyAssignOnObjectType : DiagGroup<"objc-property-assign-on-object-type">;
@@ -1038,7 +1041,7 @@ def Extra : DiagGroup<"extra", [
     EmptyInitStatement,
     StringConcatation,
     FUseLdPath,
-    CastFunctionType,
+    CastFunctionTypeMismatch,
   ]>;
 
 def Most : DiagGroup<"most", [
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 2646942a53e30d..3d8d1e420ccfef 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -9058,7 +9058,7 @@ def warn_bad_function_cast : Warning<
   InGroup<BadFunctionCast>, DefaultIgnore;
 def warn_cast_function_type : Warning<
   "cast %diff{from $ to $ |}0,1converts to incompatible function type">,
-  InGroup<CastFunctionType>, DefaultIgnore;
+  InGroup<CastFunctionTypeMismatch>, DefaultIgnore;
 def warn_cast_function_type_strict : Warning<warn_cast_function_type.Summary>,
   InGroup<CastFunctionTypeStrict>, DefaultIgnore;
 def err_cast_pointer_to_non_pointer_int : Error<
diff --git a/clang/test/Sema/warn-cast-function-type-strict.c b/clang/test/Sema/warn-cast-function-type-strict.c
index 8c88f275d2b336..b0a70cf324b711 100644
--- a/clang/test/Sema/warn-cast-function-type-strict.c
+++ b/clang/test/Sema/warn-cast-function-type-strict.c
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 %s -fsyntax-only -Wcast-function-type -verify
-// RUN: %clang_cc1 %s -fsyntax-only -Wcast-function-type-strict -verify
+// RUN: %clang_cc1 %s -fsyntax-only -Wcast-function-type -verify=expected,strict
+// RUN: %clang_cc1 %s -fsyntax-only -Wcast-function-type-strict -verify=expected,strict
 // RUN: %clang_cc1 %s -fsyntax-only -Wextra -Wno-ignored-qualifiers -verify
 
 int t(int array[static 12]);
@@ -32,13 +32,13 @@ f10 *j;
 void foo(void) {
   a = (f1 *)x;
   b = (f2 *)x; /* expected-warning {{cast from 'int (*)(long)' to 'f2 *' (aka 'int (*)(void *)') converts to incompatible function type}} */
-  c = (f3 *)x; /* expected-warning {{cast from 'int (*)(long)' to 'f3 *' (aka 'int (*)()') converts to incompatible function type}} */
+  c = (f3 *)x; /* strict-warning {{cast from 'int (*)(long)' to 'f3 *' (aka 'int (*)()') converts to incompatible function type}} */
   d = (f4 *)x; /* expected-warning {{cast from 'int (*)(long)' to 'f4 *' (aka 'void (*)()') converts to incompatible function type}} */
-  e = (f5 *)x; /* expected-warning {{cast from 'int (*)(long)' to 'f5 *' (aka 'void (*)(void)') converts to incompatible function type}} */
+  e = (f5 *)x; /* strict-warning {{cast from 'int (*)(long)' to 'f5 *' (aka 'void (*)(void)') converts to incompatible function type}} */
   f = (f6 *)x; /* expected-warning {{cast from 'int (*)(long)' to 'f6 *' (aka 'int (*)(long, int)') converts to incompatible function type}} */
-  g = (f7 *)x; /* expected-warning {{cast from 'int (*)(long)' to 'f7 *' (aka 'int (*)(long, ...)') converts to incompatible function type}} */
+  g = (f7 *)x; /* strict-warning {{cast from 'int (*)(long)' to 'f7 *' (aka 'int (*)(long, ...)') converts to incompatible function type}} */
   h = (f8 *)t;
   i = (f9 *)u;
   // FIXME: return type qualifier should not be included in the function type . Warning should be absent after this issue is fixed. https://github.com/llvm/llvm-project/issues/39494 .
-  j = (f10 *)v; /* expected-warning {{cast from 'const int (*)(int)' to 'f10 *' (aka 'int (*)(int)') converts to incompatible function type}} */
+  j = (f10 *)v; /* strict-warning {{cast from 'const int (*)(int)' to 'f10 *' (aka 'int (*)(int)') converts to incompatible function type}} */
 }
diff --git a/clang/test/SemaCXX/warn-cast-function-type-strict.cpp b/clang/test/SemaCXX/warn-cast-function-type-strict.cpp
index b3164afde5a0ca..8887b3c4c5d535 100644
--- a/clang/test/SemaCXX/warn-cast-function-type-strict.cpp
+++ b/clang/test/SemaCXX/warn-cast-function-type-strict.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 %s -fblocks -fsyntax-only -Wcast-function-type -verify
-// RUN: %clang_cc1 %s -fblocks -fsyntax-only -Wcast-function-type-strict -verify
+// RUN: %clang_cc1 %s -fblocks -fsyntax-only -Wcast-function-type -verify=expected,strict
+// RUN: %clang_cc1 %s -fblocks -fsyntax-only -Wcast-function-type-strict -verify=expected,strict
 // RUN: %clang_cc1 %s -fblocks -fsyntax-only -Wextra -verify
 
 int x(long);
@@ -33,11 +33,11 @@ void foo() {
   a = (f1 *)x;
   b = (f2 *)x; // expected-warning {{cast from 'int (*)(long)' to 'f2 *' (aka 'int (*)(void *)') converts to incompatible function type}}
   b = reinterpret_cast<f2 *>(x); // expected-warning {{cast from 'int (*)(long)' to 'f2 *' (aka 'int (*)(void *)') converts to incompatible function type}}
-  c = (f3 *)x; // expected-warning {{cast from 'int (*)(long)' to 'f3 *' (aka 'int (*)(...)') converts to incompatible function type}}
+  c = (f3 *)x; // strict-warning {{cast from 'int (*)(long)' to 'f3 *' (aka 'int (*)(...)') converts to incompatible function type}}
   d = (f4 *)x; // expected-warning {{cast from 'int (*)(long)' to 'f4 *' (aka 'void (*)(...)') converts to incompatible function type}}
-  e = (f5 *)x; // expected-warning {{cast from 'int (*)(long)' to 'f5 *' (aka 'void (*)()') converts to incompatible function type}}
+  e = (f5 *)x; // strict-warning {{cast from 'int (*)(long)' to 'f5 *' (aka 'void (*)()') converts to incompatible function type}}
   f = (f6 *)x; // expected-warning {{cast from 'int (*)(long)' to 'f6 *' (aka 'int (*)(long, int)') converts to incompatible function type}}
-  g = (f7 *)x; // expected-warning {{cast from 'int (*)(long)' to 'f7 *' (aka 'int (*)(long, ...)') converts to incompatible function type}}
+  g = (f7 *)x; // strict-warning {{cast from 'int (*)(long)' to 'f7 *' (aka 'int (*)(long, ...)') converts to incompatible function type}}
 
   mf p1 = (mf)&S::foo; // expected-warning {{cast from 'void (S::*)(int *)' to 'mf' (aka 'void (S::*)(int)') converts to incompatible function type}}

nathanchance · 2024-03-21T16:10:52Z

This seems reasonable to me. From the perspective of the Linux kernel, this seems like it should be a no-op, as we enable -Wcast-function-type and disable -Wcast-function-type-strict (under a normal build, it is on with W=1) explicitly:

$ rg 'cast-function-type(-strict)?\)' scripts/Makefile.extrawarn
57:KBUILD_CFLAGS += $(call cc-option, -Wcast-function-type)
134:KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict)

amy-kwan

I've also tested this locally, and it resolves the issue I saw earlier on the PPC bots.

AaronBallman · 2024-03-21T18:18:56Z

Thank you all for the review help on this!

amy-kwan · 2024-03-21T19:27:34Z

Thanks @AaronBallman.
Not sure how I missed it, but I just noticed in my local build of check-runtimes/check-all. This is also present on the following bot:
https://lab.llvm.org/buildbot/#/builders/57/builds/33656

Sorry for reporting this late.

Abhinkop · 2024-03-22T06:31:39Z

I think that this would occur primarily in the whole code base. Because a compilation that has added -Wextra diagnostic group would provide new warnings and coupling, this with -Werror would break the build. I think we have to take a look at these builds and investigate why it is done, and for the time being, we can use the -Wno-cast-function-type-mismatch to make the builds go green.

Abhinkop · 2024-03-22T09:09:08Z

@AaronBallman @amy-kwan I am working on a patch for this build breaking in https://lab.llvm.org/buildbot/#/builders/57/builds/33656. Is there anything else I should also be considering?

Reverts: breaks hip tests 999d4f8 Split -Wcast-function-type into a separate group (llvm#86131) Change-Id: Ia384ccb1581257a44b34390acc17d1b7516e98ad

AaronBallman · 2024-03-22T11:44:45Z

@AaronBallman @amy-kwan I am working on a patch for this build breaking in https://lab.llvm.org/buildbot/#/builders/57/builds/33656. Is there anything else I should also be considering?

Thank you for working on the patch! I would change the definition of MallocStress() in asan_noinst_test.cpp to accept a void * as expected by pthread_create(), then remove the cast in ThreadedMallocStressTest and add a cast for the call in NoInstMallocTest.

Abhinkop · 2024-03-22T12:32:37Z

Yes. I have done that. The tests failed because zlib was not enabled. Running them with a rebuild after force-enabling zlib now. Will keep you updated on the results.

amy-kwan · 2024-03-22T13:09:36Z

I have also found one more that is not related to the sanitizers, but with llvm-project/llvm/lib/IR/Core.cpp: https://lab.llvm.org/buildbot/#/builders/36/builds/43840/steps/12/logs/stdio

Would it be possible to also resolve this one, as well?

Just figured I mentioned since I am assuming the patch in progress resolves the compiler-rt ones specifically.

AaronBallman · 2024-03-22T13:23:28Z

Oof, that one is a bit messier to resolve -- it's mixing unrelated reference and pointer types and hoping the casts correctly convert back and forth properly. The fix to that should probably be done separately from the sanitizer fix so we get reasonable code review from LLVM folks.

Abhinkop · 2024-03-22T13:25:05Z

Yes, I will create a separate patch. I'm not sure it would be able to do it in this patch. I am halfway through verifying the fix in this patch. Builds and tests take a long time on my resource constraint machine.

Abhinkop · 2024-03-22T15:01:35Z

@AaronBallman @amy-kwan Here is the pull request for compiler-rt patch #86290. I am not able to add reviewers to that pull request.

amy-kwan · 2024-03-22T16:20:00Z

Thanks @Abhinkop for the patch! I have approved the compiler-rt patch since it does appear to resolve the check-runtimes/check-all issue for the asan test case.

If you also would like me to test a follow up patch for llvm-project/llvm/lib/IR/Core.cpp, I would be happy to do so, as well.

Fixed a small issue of matching pthread signature, which was causing the build to break for the compiler-rt project after adding -Wcast-function-type-mismatch to -Wextra dignostic group (#77178 & #86131).

Abhinkop · 2024-03-22T16:56:42Z

@amy-kwan I'm looking at it now. I will most probably raise a review some time later in the evening or tomorrow if I am not able to complete it today.

amy-kwan · 2024-03-22T16:58:25Z

@amy-kwan I'm looking at it now. I will most probably raise a review some time later in the evening or tomorrow if I am not able to complete it today.

Sounds good, thank you so much, @Abhinkop!

We want to add -Wcast-function-type to -Wextra (as done in 1de7e6c), but we do not want to add -Wcast-function-type-strict in at the same time (https://lab.llvm.org/buildbot/#/builders/57/builds/33601/steps/5/logs/stdio). This moves the existing warning to a new group (-Wcast-function-type-mismatch), puts the new group under the existing -Wcast-function-type warning group, and adds -Wcast-function-type-mismatch to -Wextra.

Fixed a small issue of matching pthread signature, which was causing the build to break for the compiler-rt project after adding -Wcast-function-type-mismatch to -Wextra dignostic group (llvm#77178 & llvm#86131).

amy-kwan · 2024-03-25T13:30:34Z

Hi @Abhinkop!
I was wondering if there was any progress regarding the patch to resolve the stage 2 failure, as our bot is still red (https://lab.llvm.org/buildbot/#/builders/36/builds/43929/steps/12/logs/stdio).
Please let me know if you would also like me to test any patches, as well.

Abhinkop · 2024-03-25T13:54:00Z

Hi @Abhinkop! I was wondering if there was any progress regarding the patch to resolve the stage 2 failure, as our bot is still red (https://lab.llvm.org/buildbot/#/builders/36/builds/43929/steps/12/logs/stdio). Please let me know if you would also like me to test any patches, as well.

Hey I was able to make some progress. I have raised a pr just now. #86504. But I am not sure exactly what might be the repercussions of my change. I am waiting for the builds. I have also asked on discord. Let's wait and see if someone replies.

Changing type of DiagnosticHandlerTy due to adding -Wcast-function-type-mismatch to -Wextra group(#86131 (comment)). Changed the reference argument DiagnosticInfo to a pointer and edited the test cases failing due to this change. Added another small change where Gtest api was throwing an warning due varargs argument not being passed.

AaronBallman added the clang:diagnostics New/improved warning or error message in Clang, but not in clang-tidy or static analyzer label Mar 21, 2024

AaronBallman requested review from nickdesaulniers and amy-kwan March 21, 2024 15:12

llvmbot added clang Clang issues not falling into any other category clang:frontend Language frontend issues, e.g. anything involving "Sema" labels Mar 21, 2024

AaronBallman mentioned this pull request Mar 21, 2024

[clang] move -Wcast-function-type under -Wextra #77178

Merged

nickdesaulniers requested review from kees, samitolvanen and nathanchance March 21, 2024 15:22

amy-kwan approved these changes Mar 21, 2024

View reviewed changes

thurstond mentioned this pull request Mar 21, 2024

[sanitizer_common] Suppress warning of cast from SignalHandlerType to sa_sigaction_t #86046

Merged

AaronBallman merged commit 999d4f8 into llvm:main Mar 21, 2024
8 of 9 checks passed

searlmc1 pushed a commit to ROCm/llvm-project that referenced this pull request Mar 22, 2024

merge main 999d4f8 into amd-staging

defb912

Reverts: breaks hip tests 999d4f8 Split -Wcast-function-type into a separate group (llvm#86131) Change-Id: Ia384ccb1581257a44b34390acc17d1b7516e98ad

Abhinkop mentioned this pull request Mar 22, 2024

Fixed build breaking due to #77178 and #86131 #86290

Merged

Abhinkop mentioned this pull request Mar 25, 2024

Change type of DiagnosticHandlerTy #86504

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Split -Wcast-function-type into a separate group #86131

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