tcmalloc: generalise the malloc hooks for a standards conforming libc

This creates a path for non-glibc libc implementations to add the proper hooks.
Not all libc implementations provide the same set of APIs, so reduce some of the
interfaces to the right set.

PiperOrigin-RevId: 391150233
Change-Id: I3a8c22bc222442f23840235b627116d05e54723b

Author: compnerd

tcmalloc/libc_override.h

@@ -32,7 +32,7 @@
 #include "tcmalloc/libc_override_glibc.h"
 
 #else
-#error Need to add support for your libc/OS here
+#include "tcmalloc/libc_override_redefine.h"
 
 #endif
 

tcmalloc/libc_override_redefine.h

@@ -44,38 +44,57 @@ void operator delete(void* ptr, const std::nothrow_t& nt) noexcept {
 void operator delete[](void* ptr, const std::nothrow_t& nt) noexcept {
   return TCMallocInternalDeleteArrayNothrow(ptr, nt);
 }
+
 extern "C" {
-void* malloc(size_t s) noexcept { return TCMallocInternalMalloc(s); }
-void free(void* p) noexcept { TCMallocInternalFree(p); }
-void sdallocx(void* p, size_t s, int flags) {
-  TCMallocInternalSdallocx(p, s, flags);
-}
-void* realloc(void* p, size_t s) noexcept {
-  return TCMallocInternalRealloc(p, s);
-}
-void* calloc(size_t n, size_t s) noexcept {
-  return TCMallocInternalCalloc(n, s);
-}
-void cfree(void* p) noexcept { TCMallocInternalCfree(p); }
-void* memalign(size_t a, size_t s) noexcept {
-  return TCMallocInternalMemalign(a, s);
-}
-void* valloc(size_t s) noexcept { return TCMallocInternalValloc(s); }
-void* pvalloc(size_t s) noexcept { return TCMallocInternalPvalloc(s); }
-int posix_memalign(void** r, size_t a, size_t s) noexcept {
+void* malloc(size_t s) { return TCMallocInternalMalloc(s); }
+void* calloc(size_t n, size_t s) { return TCMallocInternalCalloc(n, s); }
+void* realloc(void* p, size_t s) { return TCMallocInternalRealloc(p, s); }
+void free(void* p) { TCMallocInternalFree(p); }
+void* memalign(size_t a, size_t s) { return TCMallocInternalMemalign(a, s); }
+int posix_memalign(void** r, size_t a, size_t s) {
   return TCMallocInternalPosixMemalign(r, a, s);
 }
-void malloc_stats(void) noexcept { TCMallocInternalMallocStats(); }
-int mallopt(int cmd, int v) noexcept { return TCMallocInternalMallOpt(cmd, v); }
+size_t malloc_usable_size(void* p) { return TCMallocInternalMallocSize(p); }
+
+// tcmalloc extension
+void sdallocx(void* p, size_t s, int flags) noexcept {
+  TCMallocInternalSdallocx(p, s, flags);
+}
+
+#if defined(__GLIBC__) || defined(__NEWLIB__)
+// SunOS extension
+void cfree(void* p) { TCMallocInternalCfree(p); }
+#endif
+
+#if defined(OS_MACOSX) || defined(__BIONIC__) || defined(__GLIBC__) || \
+    defined(__NEWLIB__) || defined(__UCLIBC__)
+// Obsolete memalign
+void* valloc(size_t s) { return TCMallocInternalValloc(s); }
+#endif
+
+#if defined(__BIONIC__) || defined(__GLIBC__) || defined(__NEWLIB__)
+// Obsolete memalign
+void* pvalloc(size_t s) { return TCMallocInternalPvalloc(s); }
+#endif
+
+#if defined(__GLIBC__) || defined(__NEWLIB__) || defined(__UCLIBC__)
+void malloc_stats(void) { TCMallocInternalMallocStats(); }
+#endif
+
+#if defined(__BIONIC__) || defined(__GLIBC__) || defined(__NEWLIB__) || \
+    defined(__UCLIBC__)
+int mallopt(int cmd, int v) { return TCMallocInternalMallOpt(cmd, v); }
+#endif
+
 #ifdef TCMALLOC_HAVE_STRUCT_MALLINFO
-struct mallinfo mallinfo(void) noexcept {
+struct mallinfo mallinfo(void) {
   return TCMallocInternalMallocInfo();
 }
 #endif
-size_t malloc_size(void* p) noexcept { return TCMallocInternalMallocSize(p); }
-size_t malloc_usable_size(void* p) noexcept {
-  return TCMallocInternalMallocSize(p);
-}
+
+#if defined(__GLIBC__)
+size_t malloc_size(void* p) { return TCMallocInternalMallocSize(p); }
+#endif
 }  // extern "C"
 
 #endif  // TCMALLOC_LIBC_OVERRIDE_REDEFINE_H_