https://github.com/ian-twilightcoder created
https://github.com/llvm/llvm-project/pull/84127
On Apple platforms, some of the stddef.h types are also declared in system
headers. In particular NULL has a conflicting declaration in
<sys/_types/_null.h>. When that's in a different module from <__stddef_null.h>,
redeclaration errors can occur.
Make the __stddef_ headers be non-modular in
-fbuiltin-headers-in-system-modules and restore them back to not respecting
their header guards. Still define the header guards though.
__stddef_max_align_t.h was in _Builtin_stddef_max_align_t prior to the addition
of _Builtin_stddef, and it needs to stay in a module because struct's can't be
type merged. __stddef_wint_t.h didn't used to have a module, but leave it in it
current module since it doesn't really belong to stddef.h.
>From 0cc4b77fce06730f6a6a8b242384036018ebfe79 Mon Sep 17 00:00:00 2001
From: Ian Anderson <i...@apple.com>
Date: Tue, 5 Mar 2024 22:56:36 -0800
Subject: [PATCH] [clang][modules] giving the __stddef_ headers their own
modules can cause redeclaration errors with
-fbuiltin-headers-in-system-modules
On Apple platforms, some of the stddef.h types are also declared in system
headers. In particular NULL has a conflicting declaration in
<sys/_types/_null.h>. When that's in a different module from <__stddef_null.h>,
redeclaration errors can occur.
Make the __stddef_ headers be non-modular in
-fbuiltin-headers-in-system-modules and restore them back to not respecting
their header guards. Still define the header guards though.
__stddef_max_align_t.h was in _Builtin_stddef_max_align_t prior to the addition
of _Builtin_stddef, and it needs to stay in a module because struct's can't be
type merged. __stddef_wint_t.h didn't used to have a module, but leave it in it
current module since it doesn't really belong to stddef.h.
---
clang/lib/Basic/Module.cpp | 7 ++--
clang/lib/Headers/__stddef_null.h | 2 +-
clang/lib/Headers/__stddef_nullptr_t.h | 6 +++-
clang/lib/Headers/__stddef_offsetof.h | 6 +++-
clang/lib/Headers/__stddef_ptrdiff_t.h | 6 +++-
clang/lib/Headers/__stddef_rsize_t.h | 6 +++-
clang/lib/Headers/__stddef_size_t.h | 6 +++-
clang/lib/Headers/__stddef_unreachable.h | 6 +++-
clang/lib/Headers/__stddef_wchar_t.h | 6 +++-
clang/lib/Headers/module.modulemap | 20 ++++++------
clang/lib/Lex/ModuleMap.cpp | 9 ++++--
.../no-undeclared-includes-builtins.cpp | 2 +-
clang/test/Modules/stddef.c | 32 +++++++++++--------
13 files changed, 73 insertions(+), 41 deletions(-)
diff --git a/clang/lib/Basic/Module.cpp b/clang/lib/Basic/Module.cpp
index 1c5043a618fff3..f68a556fb455bf 100644
--- a/clang/lib/Basic/Module.cpp
+++ b/clang/lib/Basic/Module.cpp
@@ -301,10 +301,9 @@ bool Module::directlyUses(const Module *Requested) {
if (Requested->isSubModuleOf(Use))
return true;
- // Anyone is allowed to use our builtin stdarg.h and stddef.h and their
- // accompanying modules.
- if (Requested->getTopLevelModuleName() == "_Builtin_stdarg" ||
- Requested->getTopLevelModuleName() == "_Builtin_stddef")
+ // Anyone is allowed to use our builtin stddef.h and its accompanying
modules.
+ if (Requested->fullModuleNameIs({"_Builtin_stddef", "max_align_t"}) ||
+ Requested->fullModuleNameIs({"_Builtin_stddef_wint_t"}))
return true;
if (NoUndeclaredIncludes)
diff --git a/clang/lib/Headers/__stddef_null.h
b/clang/lib/Headers/__stddef_null.h
index 7336fdab389723..c10bd2d7d9887c 100644
--- a/clang/lib/Headers/__stddef_null.h
+++ b/clang/lib/Headers/__stddef_null.h
@@ -7,7 +7,7 @@
*===-----------------------------------------------------------------------===
*/
-#if !defined(NULL) || !__has_feature(modules)
+#if !defined(NULL) || !__building_module(_Builtin_stddef)
/* linux/stddef.h will define NULL to 0. glibc (and other) headers then define
* __need_NULL and rely on stddef.h to redefine NULL to the correct value
again.
diff --git a/clang/lib/Headers/__stddef_nullptr_t.h
b/clang/lib/Headers/__stddef_nullptr_t.h
index 183d394d56c1b7..d724b5cba18294 100644
--- a/clang/lib/Headers/__stddef_nullptr_t.h
+++ b/clang/lib/Headers/__stddef_nullptr_t.h
@@ -7,7 +7,11 @@
*===-----------------------------------------------------------------------===
*/
-#ifndef _NULLPTR_T
+/*
+ * When -fbuiltin-headers-in-system-modules is set this is a non-modular header
+ * and needs to behave as if it was textual.
+ */
+#if !defined(_NULLPTR_T) || (__has_feature(modules) &&
!__building_module(_Builtin_stddef))
#define _NULLPTR_T
#ifdef __cplusplus
diff --git a/clang/lib/Headers/__stddef_offsetof.h
b/clang/lib/Headers/__stddef_offsetof.h
index 3b347b3b92f62c..62c49c78bd0516 100644
--- a/clang/lib/Headers/__stddef_offsetof.h
+++ b/clang/lib/Headers/__stddef_offsetof.h
@@ -7,6 +7,10 @@
*===-----------------------------------------------------------------------===
*/
-#ifndef offsetof
+/*
+ * When -fbuiltin-headers-in-system-modules is set this is a non-modular header
+ * and needs to behave as if it was textual.
+ */
+#if !defined(offsetof) || (__has_feature(modules) &&
!__building_module(_Builtin_stddef))
#define offsetof(t, d) __builtin_offsetof(t, d)
#endif
diff --git a/clang/lib/Headers/__stddef_ptrdiff_t.h
b/clang/lib/Headers/__stddef_ptrdiff_t.h
index 3ea6d7d2852e1c..31ecc00b624602 100644
--- a/clang/lib/Headers/__stddef_ptrdiff_t.h
+++ b/clang/lib/Headers/__stddef_ptrdiff_t.h
@@ -7,7 +7,11 @@
*===-----------------------------------------------------------------------===
*/
-#ifndef _PTRDIFF_T
+/*
+ * When -fbuiltin-headers-in-system-modules is set this is a non-modular header
+ * and needs to behave as if it was textual.
+ */
+#if !defined(_PTRDIFF_T) || (__has_feature(modules) &&
!__building_module(_Builtin_stddef))
#define _PTRDIFF_T
typedef __PTRDIFF_TYPE__ ptrdiff_t;
diff --git a/clang/lib/Headers/__stddef_rsize_t.h
b/clang/lib/Headers/__stddef_rsize_t.h
index b6428d0c12b62a..9cb9c266116cf7 100644
--- a/clang/lib/Headers/__stddef_rsize_t.h
+++ b/clang/lib/Headers/__stddef_rsize_t.h
@@ -7,7 +7,11 @@
*===-----------------------------------------------------------------------===
*/
-#ifndef _RSIZE_T
+/*
+ * When -fbuiltin-headers-in-system-modules is set this is a non-modular header
+ * and needs to behave as if it was textual.
+ */
+#if !defined(_RSIZE_T) || (__has_feature(modules) &&
!__building_module(_Builtin_stddef))
#define _RSIZE_T
typedef __SIZE_TYPE__ rsize_t;
diff --git a/clang/lib/Headers/__stddef_size_t.h
b/clang/lib/Headers/__stddef_size_t.h
index e4a389510bcdbf..01d3a0c4802c70 100644
--- a/clang/lib/Headers/__stddef_size_t.h
+++ b/clang/lib/Headers/__stddef_size_t.h
@@ -7,7 +7,11 @@
*===-----------------------------------------------------------------------===
*/
-#ifndef _SIZE_T
+/*
+ * When -fbuiltin-headers-in-system-modules is set this is a non-modular header
+ * and needs to behave as if it was textual.
+ */
+#if !defined(_SIZE_T) || (__has_feature(modules) &&
!__building_module(_Builtin_stddef))
#define _SIZE_T
typedef __SIZE_TYPE__ size_t;
diff --git a/clang/lib/Headers/__stddef_unreachable.h
b/clang/lib/Headers/__stddef_unreachable.h
index 3e7fe01979662a..1f9254f6bb5753 100644
--- a/clang/lib/Headers/__stddef_unreachable.h
+++ b/clang/lib/Headers/__stddef_unreachable.h
@@ -7,6 +7,10 @@
*===-----------------------------------------------------------------------===
*/
-#ifndef unreachable
+/*
+ * When -fbuiltin-headers-in-system-modules is set this is a non-modular header
+ * and needs to behave as if it was textual.
+ */
+#if !defined(unreachable) || (__has_feature(modules) &&
!__building_module(_Builtin_stddef))
#define unreachable() __builtin_unreachable()
#endif
diff --git a/clang/lib/Headers/__stddef_wchar_t.h
b/clang/lib/Headers/__stddef_wchar_t.h
index 16a6186512c0c3..4239f619f085d9 100644
--- a/clang/lib/Headers/__stddef_wchar_t.h
+++ b/clang/lib/Headers/__stddef_wchar_t.h
@@ -9,7 +9,11 @@
#if !defined(__cplusplus) || (defined(_MSC_VER) && !_NATIVE_WCHAR_T_DEFINED)
-#ifndef _WCHAR_T
+/*
+ * When -fbuiltin-headers-in-system-modules is set this is a non-modular header
+ * and needs to behave as if it was textual.
+ */
+#if !defined(_WCHAR_T) || (__has_feature(modules) &&
!__building_module(_Builtin_stddef))
#define _WCHAR_T
#ifdef _MSC_EXTENSIONS
diff --git a/clang/lib/Headers/module.modulemap
b/clang/lib/Headers/module.modulemap
index a786689d391773..56a13f69bc0559 100644
--- a/clang/lib/Headers/module.modulemap
+++ b/clang/lib/Headers/module.modulemap
@@ -155,9 +155,9 @@ module _Builtin_intrinsics [system] [extern_c] {
// Start -fbuiltin-headers-in-system-modules affected modules
-// The following modules all ignore their top level headers
-// when -fbuiltin-headers-in-system-modules is passed, and
-// most of those headers join system modules when present.
+// The following modules all ignore their headers when
+// -fbuiltin-headers-in-system-modules is passed, and many of
+// those headers join system modules when present.
// e.g. if -fbuiltin-headers-in-system-modules is passed, then
// float.h will not be in the _Builtin_float module (that module
@@ -190,11 +190,6 @@ module _Builtin_stdalign [system] {
export *
}
-// When -fbuiltin-headers-in-system-modules is passed, only
-// the top level headers are removed, the implementation headers
-// will always be in their submodules. That means when stdarg.h
-// is included, it will still import this module and make the
-// appropriate submodules visible.
module _Builtin_stdarg [system] {
textual header "stdarg.h"
@@ -237,6 +232,8 @@ module _Builtin_stdbool [system] {
module _Builtin_stddef [system] {
textual header "stddef.h"
+ // __stddef_max_align_t.h is always in this module, even if
+ // -fbuiltin-headers-in-system-modules is passed.
explicit module max_align_t {
header "__stddef_max_align_t.h"
export *
@@ -283,9 +280,10 @@ module _Builtin_stddef [system] {
}
}
-/* wint_t is provided by <wchar.h> and not <stddef.h>. It's here
- * for compatibility, but must be explicitly requested. Therefore
- * __stddef_wint_t.h is not part of _Builtin_stddef. */
+// wint_t is provided by <wchar.h> and not <stddef.h>. It's here
+// for compatibility, but must be explicitly requested. Therefore
+// __stddef_wint_t.h is not part of _Builtin_stddef. It is always in
+// this module even if -fbuiltin-headers-in-system-modules is passed.
module _Builtin_stddef_wint_t [system] {
header "__stddef_wint_t.h"
export *
diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index afb2948f05ae5b..10c475f617d485 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -2498,9 +2498,12 @@ void ModuleMapParser::parseHeaderDecl(MMToken::TokenKind
LeadingToken,
}
bool NeedsFramework = false;
- // Don't add the top level headers to the builtin modules if the builtin
headers
- // belong to the system modules.
- if (!Map.LangOpts.BuiltinHeadersInSystemModules ||
ActiveModule->isSubModule() || !isBuiltInModuleName(ActiveModule->Name))
+ // Don't add headers to the builtin modules if the builtin headers belong to
+ // the system modules, with the exception of __stddef_max_align_t.h which
+ // always had its own module.
+ if (!Map.LangOpts.BuiltinHeadersInSystemModules ||
+ !isBuiltInModuleName(ActiveModule->getTopLevelModuleName()) ||
+ ActiveModule->fullModuleNameIs({"_Builtin_stddef", "max_align_t"}))
Map.addUnresolvedHeader(ActiveModule, std::move(Header), NeedsFramework);
if (NeedsFramework)
diff --git a/clang/test/Modules/no-undeclared-includes-builtins.cpp
b/clang/test/Modules/no-undeclared-includes-builtins.cpp
index c9bffc55619905..f9eefd24a33c7d 100644
--- a/clang/test/Modules/no-undeclared-includes-builtins.cpp
+++ b/clang/test/Modules/no-undeclared-includes-builtins.cpp
@@ -8,7 +8,7 @@
// headers.
// RUN: rm -rf %t
-// RUN: %clang_cc1 -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I
%S/Inputs/no-undeclared-includes-builtins/libcxx -I
%S/Inputs/no-undeclared-includes-builtins/glibc %s
+// RUN: %clang_cc1 -fmodules-cache-path=%t -fmodules
-fbuiltin-headers-in-system-modules -fimplicit-module-maps -I
%S/Inputs/no-undeclared-includes-builtins/libcxx -I
%S/Inputs/no-undeclared-includes-builtins/glibc %s
// expected-no-diagnostics
#include <stddef.h>
diff --git a/clang/test/Modules/stddef.c b/clang/test/Modules/stddef.c
index 5bc0d1e44c8563..76239826146810 100644
--- a/clang/test/Modules/stddef.c
+++ b/clang/test/Modules/stddef.c
@@ -1,29 +1,33 @@
// RUN: rm -rf %t
-// RUN: %clang_cc1 -fmodules -fimplicit-module-maps
-fbuiltin-headers-in-system-modules -fmodules-cache-path=%t -I%S/Inputs/StdDef
%s -verify -fno-modules-error-recovery
+// RUN: %clang_cc1 -fmodules -fimplicit-module-maps
-fbuiltin-headers-in-system-modules -fmodules-cache-path=%t -I%S/Inputs/StdDef
%s -verify=builtin-headers-in-system-modules -fno-modules-error-recovery
// RUN: rm -rf %t
-// RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t
-I%S/Inputs/StdDef %s -verify -fno-modules-error-recovery
+// RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t
-I%S/Inputs/StdDef %s -verify=no-builtin-headers-in-system-modules
-fno-modules-error-recovery
#include "ptrdiff_t.h"
ptrdiff_t pdt;
-// size_t is declared in both size_t.h and __stddef_size_t.h, both of which are
-// modular headers. Regardless of whether stddef.h joins the StdDef test module
-// or is in its _Builtin_stddef module, __stddef_size_t.h will be in
-// _Builtin_stddef.size_t. It's not defined which module will win as the
expected
-// provider of size_t. For the purposes of this test it doesn't matter which
header
-// gets reported, just as long as it isn't other.h or include_again.h.
-size_t st; // expected-error-re {{missing '#include
"{{size_t|__stddef_size_t}}.h"'; 'size_t' must be declared before it is used}}
-// expected-note@size_t.h:* 0+ {{here}}
-// expected-note@__stddef_size_t.h:* 0+ {{here}}
+// size_t is declared in both size_t.h and __stddef_size_t.h. If
+// -fbuiltin-headers-in-system-modules is set, then __stddef_size_t.h is a
+// non-modular header that will be transitively pulled in the StdDef test
module
+// by include_again.h. Otherwise it will be in the _Builtin_stddef module. In
+// any case it's not defined which module will win as the expected provider of
+// size_t. For the purposes of this test it doesn't matter which of the two
+// providing headers get reported.
+size_t st; // builtin-headers-in-system-modules-error-re {{missing '#include
"{{size_t|include_again}}.h"'; 'size_t' must be declared before it is used}} \
+ no-builtin-headers-in-system-modules-error-re {{missing
'#include "{{size_t|__stddef_size_t}}.h"'; 'size_t' must be declared before it
is used}}
+// builtin-headers-in-system-modules-note@size_t.h:* 0+ {{here}} \
+ no-builtin-headers-in-system-modules-note@size_t.h:* 0+ {{here}}
+// builtin-headers-in-system-modules-note@__stddef_size_t.h:* 0+ {{here}} \
+ no-builtin-headers-in-system-modules-note@__stddef_size_t.h:* 0+ {{here}}
#include "include_again.h"
-// Includes <stddef.h> which includes <__stddef_size_t.h> which imports the
-// _Builtin_stddef.size_t module.
+// Includes <stddef.h> which includes <__stddef_size_t.h>.
size_t st2;
#include "size_t.h"
-// Redeclares size_t, but the type merger should figure it out.
+// Redeclares size_t when -fbuiltin-headers-in-system-modules is not passed,
but
+// the type merger should figure it out.
size_t st3;
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