1 files changed, 49 insertions, 19 deletions

diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index 18f26b2..3310e3a 100644
--- a/include/libc-symbols.h
+++ b/include/libc-symbols.h
@@ -20,26 +20,46 @@
 #ifndef _LIBC_SYMBOLS_H
 #define _LIBC_SYMBOLS_H	1
 
-#define IN_MODULE PASTE_NAME (MODULE_, MODULE_NAME)
-#define IS_IN(lib) (IN_MODULE == MODULE_##lib)
+/* This file is included implicitly in the compilation of every source file,
+   using -include.  It includes config.h.  */
 
-/* Returns true if the current module is a versioned library.  Versioned
-   library names culled from shlib-versions files are assigned a MODULE_*
-   value lower than MODULE_LIBS_BEGIN.  */
-#define IS_IN_LIB (IN_MODULE > MODULE_LIBS_BEGIN)
-
-#define PASTE_NAME(a,b)      PASTE_NAME1 (a,b)
-#define PASTE_NAME1(a,b)     a##b
-
-/* This file's macros are included implicitly in the compilation of every
-   file in the C library by -imacros.
-
-   We include config.h which is generated by configure.
-   It should define for us the following symbol:
+/* Enable declarations of GNU extensions, since we are compiling them.  */
+#define _GNU_SOURCE 1
+
+#ifdef MODULE_NAME
+
+/* Use `#if IS_IN (module)` to detect what component is being compiled.  */
+#define PASTE_NAME1(a,b) a##b
+#define PASTE_NAME(a,b)	 PASTE_NAME1 (a,b)
+#define IN_MODULE	 PASTE_NAME (MODULE_, MODULE_NAME)
+#define IS_IN(lib)	 (IN_MODULE == MODULE_##lib)
+
+/* True if the current module is a versioned library.  Versioned
+   library names culled from shlib-versions files are assigned a
+   MODULE_* value greater than MODULE_LIBS_BEGIN.  */
+#define IS_IN_LIB	 (IN_MODULE > MODULE_LIBS_BEGIN)
+
+/* The testsuite, and some other ancillary code, should be compiled against
+   as close an approximation to the installed headers as possible.
+   Defining this symbol disables most internal-use-only declarations
+   provided by this header, and all those provided by other internal
+   wrapper headers.  */
+#if IS_IN (testsuite) || defined IS_IN_build || defined __cplusplus
+# define _ISOMAC 1
+#endif
 
-   * HAVE_ASM_SET_DIRECTIVE if we have `.set B, A' instead of `A = B'.
+#else
+/* The generation process for a few files created very early in the
+   build (notably libc-modules.h itself) involves preprocessing this
+   header without defining MODULE_NAME.  Under these conditions,
+   internal declarations (especially from config.h) must be visible,
+   but IS_IN should always evaluate as false.  */
+# define IS_IN(lib) 0
+# define IS_IN_LIB 0
+# define IN_MODULE (-1)
+#endif
 
-   */
+#ifndef _ISOMAC
 
 /* This is defined for the compilation of all C library code.  features.h
    tests this to avoid inclusion of stubs.h while compiling the library,
@@ -50,8 +70,17 @@
    itself is being compiled, or just some generator program.  */
 #define _LIBC	1
 
-/* Enable declarations of GNU extensions, since we are compiling them.  */
-#define _GNU_SOURCE	1
+/* Some files must be compiled with optimization on.  */
+#if !defined __ASSEMBLER__ && !defined __OPTIMIZE__
+# error "glibc cannot be compiled without optimization"
+#endif
+
+/* -ffast-math cannot be applied to the C library, as it alters the ABI.
+   Some test components that use -ffast-math are currently not part of
+   IS_IN (testsuite) for technical reasons, so we have a secondary override.  */
+#if defined __FAST_MATH__ && !defined TEST_FAST_MATH
+# error "glibc must not be compiled with -ffast-math"
+#endif
 
 #include <config.h>
 
@@ -936,4 +965,5 @@ for linking")
 # define _GL_ATTRIBUTE_CONST /* empty */
 #endif
 
+#endif /* !_ISOMAC */
 #endif /* libc-symbols.h */