[C2y] Claim support for WG14 N3623 #162843
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This requires invalid signatures of main to be diagnosed while still allowing for common extensions. Clang has always supported this.
AaronBallman
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clang
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@llvm/pr-subscribers-clang Author: Aaron Ballman (AaronBallman) ChangesThis requires invalid signatures of main to be diagnosed while still allowing for common extensions. Clang has always supported this. Full diff: https://github.com/llvm/llvm-project/pull/162843.diff 2 Files Affected:
diff --git a/clang/test/C/C2y/n3623.c b/clang/test/C/C2y/n3623.c
new file mode 100644
index 0000000000000..a557edadae078
--- /dev/null
+++ b/clang/test/C/C2y/n3623.c
@@ -0,0 +1,74 @@
+// RUN: %clang_cc1 -verify -std=c2y -DSTD1 %s
+// RUN: %clang_cc1 -verify -std=c2y -DSTD2 %s
+// RUN: %clang_cc1 -verify=gnu1 -std=gnu2y -DGNU1 %s
+// RUN: %clang_cc1 -verify -std=gnu2y -DGNU2 %s
+// RUN: %clang_cc1 -verify=gnu3 -std=gnu2y -DGNU3 %s
+// RUN: %clang_cc1 -verify -std=gnu2y -DGNU4 %s
+// RUN: %clang_cc1 -verify -std=gnu2y -DGNU5 %s
+// RUN: %clang_cc1 -verify -std=gnu2y -DGNU6 %s
+// RUN: %clang_cc1 -verify=gnu7 -std=gnu2y -DGNU7 %s
+// RUN: %clang_cc1 -triple x86_64-apple-darwin12 -verify -std=c2y -DDARWIN1 %s
+// RUN: %clang_cc1 -triple x86_64-pc-win32-mscv -verify -std=c2y -fms-compatibility -DMS1 %s
+// RUN: %clang_cc1 -triple x86_64-pc-win32-mscv -verify -std=c2y -fms-compatibility -DMS2 %s
+// RUN: %clang_cc1 -verify=invalid -std=c2y -DINVALID1 %s
+// RUN: %clang_cc1 -verify=invalid -std=c2y -DINVALID2 %s
+// expected-no-diagnostics
+
+/* WG14 N3623: Yes
+ * Earthly Demon XV: Definition of Main
+ *
+ * This validates that we accept the standard type definitions of main or some
+ * other implementation-defined type.
+ */
+
+typedef __WCHAR_TYPE__ wchar_t;
+
+// These are the signatures required by the standard.
+#if defined(STD1)
+int main(void) {}
+#elif defined(STD2)
+int main(int argc, char *argv[]) {}
+#endif
+
+// GNU extensions.
+#if defined(GNU1)
+void main(void) {} /* gnu1-warning {{return type of 'main' is not 'int'}}
+ gnu1-note {{change return type to 'int'}}
+ */
+#elif defined(GNU2)
+const int main(void) {}
+#elif defined(GNU3)
+int main(...) {} /* gnu3-warning {{'main' is not allowed to be declared variadic}} */
+#elif defined(GNU4)
+int main(int, const char **) {}
+#elif defined(GNU5)
+int main(int, char const * const *) {}
+#elif defined(GNU6)
+int main(int, char * const *) {}
+#elif defined(GNU7)
+int main(int) {} /* gnu7-warning {{only one parameter on 'main' declaration}} */
+#endif
+
+// Darwin extensions.
+#if defined(DARWIN1)
+int main(int argc, char *argv[], char *environ[], char **undocumented) {}
+#endif
+
+// Microsoft extensions.
+#if defined(MS1)
+int wmain(int, wchar_t *[]) {}
+#elif defined(MS2)
+int wmain(int, wchar_t *[], wchar_t *[]) {}
+#endif
+
+// Invalid signatures.
+#if defined(INVALID1)
+inline int main(int, char *[]); /* invalid-error {{'main' is not allowed to be declared inline}} */
+int main(int, char *[], char *[], float); /* invalid-error {{too many parameters (4) for 'main': must be 0, 2, or 3}} */
+float main(int); /* invalid-error {{'main' must return 'int'}} */
+_Noreturn int main(int, char *[]); /* invalid-warning {{'main' is not allowed to be declared _Noreturn}}
+ invalid-note {{remove '_Noreturn'}}
+ */
+#elif defined(INVALID2)
+static int main(void); /* invalid-warning {{'main' should not be declared static}} */
+#endif
diff --git a/clang/www/c_status.html b/clang/www/c_status.html
index f16c40202aa21..a6bcd4c197133 100644
--- a/clang/www/c_status.html
+++ b/clang/www/c_status.html
@@ -339,7 +339,7 @@ <h2 id="c2y">C2y implementation status</h2>
<tr>
<td>Earthly Demon XV: Definition of Main</td>
<td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3623.pdf">N3623</a></td>
- <td class="unknown" align="center">Unknown</td>
+ <td class="full" align="center">Yes</td>
</tr>
<tr>
<td>static_assert without UB</td>
|
cor3ntin
approved these changes
Oct 10, 2025
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/28819 Here is the relevant piece of the build log for the reference |
|
Seems to fail on mac: http://45.33.8.238/macm1/115293/step_6.txt …oh, llvm-ci already said this above too. Looking? |
Yup, investigating and will either fix or revert shortly. |
AaronBallman
added a commit
that referenced
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Oct 10, 2025
#162843 landed a test that is broken on darwin: https://lab.llvm.org/buildbot/#/builders/190/builds/28819 This is an attempted quick fix.
|
f6caec6 should hopefully fix things up, I'll watch the bot |
llvm-sync bot
pushed a commit
to arm/arm-toolchain
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Oct 10, 2025
llvm/llvm-project#162843 landed a test that is broken on darwin: https://lab.llvm.org/buildbot/#/builders/190/builds/28819 This is an attempted quick fix.
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This requires invalid signatures of main to be diagnosed while still allowing for common extensions. Clang has always supported this.