Merge pull request #8706 from ian-twilightcoder/no-decl-in-textual

fredriss · web-flow · commit f9439cbe9ab3 · 2024-05-07T11:13:31.000-07:00
[cherry-pick swift/release/6.0][clang][modules] stdarg.h and stddef.h shouldn't directly declare anything
diff --git a/clang-tools-extra/clang-include-fixer/find-all-symbols/STLPostfixHeaderMap.cpp b/clang-tools-extra/clang-include-fixer/find-all-symbols/STLPostfixHeaderMap.cpp
@@ -15,9 +15,11 @@ const HeaderMapCollector::RegexHeaderMap *getSTLPostfixHeaderMap() {
   static const HeaderMapCollector::RegexHeaderMap STLPostfixHeaderMap = {
       {"include/__stdarg___gnuc_va_list.h$", "<cstdarg>"},
       {"include/__stdarg___va_copy.h$", "<cstdarg>"},
+      {"include/__stdarg_header_macro.h$", "<cstdarg>"},
       {"include/__stdarg_va_arg.h$", "<cstdarg>"},
       {"include/__stdarg_va_copy.h$", "<cstdarg>"},
       {"include/__stdarg_va_list.h$", "<cstdarg>"},
+      {"include/__stddef_header_macro.h$", "<cstddef>"},
       {"include/__stddef_max_align_t.h$", "<cstddef>"},
       {"include/__stddef_null.h$", "<cstddef>"},
       {"include/__stddef_nullptr_t.h$", "<cstddef>"},
diff --git a/clang-tools-extra/clangd/index/CanonicalIncludes.cpp b/clang-tools-extra/clangd/index/CanonicalIncludes.cpp
@@ -18,9 +18,11 @@ namespace {
 const std::pair<llvm::StringRef, llvm::StringRef> IncludeMappings[] = {
     {"include/__stdarg___gnuc_va_list.h", "<cstdarg>"},
     {"include/__stdarg___va_copy.h", "<cstdarg>"},
+    {"include/__stdarg_header_macro.h", "<cstdarg>"},
     {"include/__stdarg_va_arg.h", "<cstdarg>"},
     {"include/__stdarg_va_copy.h", "<cstdarg>"},
     {"include/__stdarg_va_list.h", "<cstdarg>"},
+    {"include/__stddef_header_macro.h", "<cstddef>"},
     {"include/__stddef_max_align_t.h", "<cstddef>"},
     {"include/__stddef_null.h", "<cstddef>"},
     {"include/__stddef_nullptr_t.h", "<cstddef>"},
diff --git a/clang/lib/Headers/CMakeLists.txt b/clang/lib/Headers/CMakeLists.txt
@@ -12,12 +12,14 @@ set(core_files
   stdarg.h
   __stdarg___gnuc_va_list.h
   __stdarg___va_copy.h
+  __stdarg_header_macro.h
   __stdarg_va_arg.h
   __stdarg_va_copy.h
   __stdarg_va_list.h
   stdatomic.h
   stdbool.h
   stddef.h
+  __stddef_header_macro.h
   __stddef_max_align_t.h
   __stddef_null.h
   __stddef_nullptr_t.h
diff --git a/clang/lib/Headers/__stdarg_header_macro.h b/clang/lib/Headers/__stdarg_header_macro.h
@@ -0,0 +1,12 @@
+/*===---- __stdarg_header_macro.h ------------------------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __STDARG_H
+#define __STDARG_H
+#endif
diff --git a/clang/lib/Headers/__stddef_header_macro.h b/clang/lib/Headers/__stddef_header_macro.h
@@ -0,0 +1,12 @@
+/*===---- __stddef_header_macro.h ------------------------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __STDDEF_H
+#define __STDDEF_H
+#endif
diff --git a/clang/lib/Headers/module.modulemap b/clang/lib/Headers/module.modulemap
@@ -203,6 +203,11 @@ module _Builtin_stdarg [system] {
     export *
   }
 
+  explicit module header_macro {
+    header "__stdarg_header_macro.h"
+    export *
+  }
+
   explicit module va_arg {
     header "__stdarg_va_arg.h"
     export *
@@ -232,6 +237,10 @@ module _Builtin_stdbool [system] {
 module _Builtin_stddef [system] {
   textual header "stddef.h"
 
+  explicit module header_macro {
+    header "__stddef_header_macro.h"
+    export *
+  }
   // __stddef_max_align_t.h is always in this module, even if
   // -fbuiltin-headers-in-system-modules is passed.
   explicit module max_align_t {
diff --git a/clang/lib/Headers/stdarg.h b/clang/lib/Headers/stdarg.h
@@ -14,29 +14,15 @@
  * need to use some of its interfaces. Otherwise this header provides all of
  * the expected interfaces.
  *
- * When clang modules are enabled, this header is a textual header. It ignores
- * its header guard so that multiple submodules can export its interfaces.
- * Take module SM with submodules A and B, whose headers both include stdarg.h
- * When SM.A builds, __STDARG_H will be defined. When SM.B builds, the
- * definition from SM.A will leak when building without local submodule
- * visibility. stdarg.h wouldn't include any of its implementation headers, and
- * SM.B wouldn't import any of the stdarg modules, and SM.B's `export *`
- * wouldn't export any stdarg interfaces as expected. However, since stdarg.h
- * ignores its header guard when building with modules, it all works as
- * expected.
- *
- * When clang modules are not enabled, the header guards can function in the
- * normal simple fashion.
+ * When clang modules are enabled, this header is a textual header to support
+ * the multiple include behavior. As such, it doesn't directly declare anything
+ * so that it doesn't add duplicate declarations to all of its includers'
+ * modules.
  */
-#if !defined(__STDARG_H) || __has_feature(modules) ||                          \
-    defined(__need___va_list) || defined(__need_va_list) ||                    \
-    defined(__need_va_arg) || defined(__need___va_copy) ||                     \
-    defined(__need_va_copy)
-
 #if !defined(__need___va_list) && !defined(__need_va_list) &&                  \
     !defined(__need_va_arg) && !defined(__need___va_copy) &&                   \
     !defined(__need_va_copy)
-#define __STDARG_H
+#include <__stdarg_header_macro.h>
 #define __need___va_list
 #define __need_va_list
 #define __need_va_arg
@@ -75,5 +61,3 @@
 #include <__stdarg_va_copy.h>
 #undef __need_va_copy
 #endif /* defined(__need_va_copy) */
-
-#endif
diff --git a/clang/lib/Headers/stddef.h b/clang/lib/Headers/stddef.h
@@ -14,19 +14,10 @@
  * need to use some of its interfaces. Otherwise this header provides all of
  * the expected interfaces.
  *
- * When clang modules are enabled, this header is a textual header. It ignores
- * its header guard so that multiple submodules can export its interfaces.
- * Take module SM with submodules A and B, whose headers both include stddef.h
- * When SM.A builds, __STDDEF_H will be defined. When SM.B builds, the
- * definition from SM.A will leak when building without local submodule
- * visibility. stddef.h wouldn't include any of its implementation headers, and
- * SM.B wouldn't import any of the stddef modules, and SM.B's `export *`
- * wouldn't export any stddef interfaces as expected. However, since stddef.h
- * ignores its header guard when building with modules, it all works as
- * expected.
- *
- * When clang modules are not enabled, the header guards can function in the
- * normal simple fashion.
+ * When clang modules are enabled, this header is a textual header to support
+ * the multiple include behavior. As such, it doesn't directly declare anything
+ * so that it doesn't add duplicate declarations to all of its includers'
+ * modules.
  */
 
 #if defined(__musl__)
@@ -36,20 +27,12 @@
 
 #else
 
-#if !defined(__STDDEF_H) || __has_feature(modules) ||                          \
-    (defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ >= 1) ||        \
-    defined(__need_ptrdiff_t) || defined(__need_size_t) ||                     \
-    defined(__need_rsize_t) || defined(__need_wchar_t) ||                      \
-    defined(__need_NULL) || defined(__need_nullptr_t) ||                       \
-    defined(__need_unreachable) || defined(__need_max_align_t) ||              \
-    defined(__need_offsetof) || defined(__need_wint_t)
-
 #if !defined(__need_ptrdiff_t) && !defined(__need_size_t) &&                   \
     !defined(__need_rsize_t) && !defined(__need_wchar_t) &&                    \
     !defined(__need_NULL) && !defined(__need_nullptr_t) &&                     \
     !defined(__need_unreachable) && !defined(__need_max_align_t) &&            \
     !defined(__need_offsetof) && !defined(__need_wint_t)
-#define __STDDEF_H
+#include <__stddef_header_macro.h>
 #define __need_ptrdiff_t
 #define __need_size_t
 /* ISO9899:2011 7.20 (C11 Annex K): Define rsize_t if __STDC_WANT_LIB_EXT1__ is
@@ -130,6 +113,4 @@ __WINT_TYPE__ directly; accommodate both by requiring __need_wint_t */
 #undef __need_wint_t
 #endif /* __need_wint_t */
 
-#endif
-
 #endif /* !defined(__musl__) */
diff --git a/llvm/utils/gn/secondary/clang/lib/Headers/BUILD.gn b/llvm/utils/gn/secondary/clang/lib/Headers/BUILD.gn
@@ -97,9 +97,11 @@ copy("Headers") {
     "__clang_hip_stdlib.h",
     "__stdarg___gnuc_va_list.h",
     "__stdarg___va_copy.h",
+    "__stdarg_header_macro.h",
     "__stdarg_va_arg.h",
     "__stdarg_va_copy.h",
     "__stdarg_va_list.h",
+    "__stddef_header_macro.h",
     "__stddef_max_align_t.h",
     "__stddef_null.h",
     "__stddef_nullptr_t.h",
