GN: aix port along with linux_s390x, linux_ppc64 and linux_ppc64le support.

base/allocator/allocator_shim_default_dispatch_to_glibc.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/allocator/allocator_shim.h"
 
 #include <malloc.h>
 
+// This is required for posix_memalign
+#if defined(OS_AIX)
+#include <stdlib.h>
+#endif
+
 // This translation unit defines a default dispatch for the allocator shim which
 // routes allocations to libc functions.
 // The code here is strongly inspired from tcmalloc's libc_override_glibc.h.
 
 extern "C" {
 void* __libc_malloc(size_t size);
 void* __libc_calloc(size_t n, size_t size);
 void* __libc_realloc(void* address, size_t size);
 void* __libc_memalign(size_t alignment, size_t size);
 void __libc_free(void* ptr);
 }  // extern "C"
 
 namespace {
 
 using base::allocator::AllocatorDispatch;
 
 void* GlibcMalloc(const AllocatorDispatch*, size_t size, void* context) {
+#if defined(OS_AIX)
+  return malloc(size);

[Primiano Tucci (use gerrit), 2017/04/13 09:59:14]

this is just going to cause loops in the malloc code.
I think you just want to set
use_experimental_allocator_shim = false
in your builds

this will avoid this entire logic to kick in, without having to change these
files.

+#else
   return __libc_malloc(size);
+#endif
 }
 
 void* GlibcCalloc(const AllocatorDispatch*,
                   size_t n,
                   size_t size,
                   void* context) {
+#if defined(OS_AIX)
+  return calloc(n, size);
+#else
   return __libc_calloc(n, size);
+#endif
 }
 
 void* GlibcRealloc(const AllocatorDispatch*,
                    void* address,
                    size_t size,
                    void* context) {
+#if defined(OS_AIX)
+  return realloc(address, size);
+#else
   return __libc_realloc(address, size);
+#endif
 }
 
 void* GlibcMemalign(const AllocatorDispatch*,
                     size_t alignment,
                     size_t size,
                     void* context) {
+#if defined(OS_AIX)
+  void* p;
+  if (posix_memalign(&p, alignment, size) == 0)
+    return p;
+  else
+    return NULL;
+#else
   return __libc_memalign(alignment, size);
+#endif
 }
 
 void GlibcFree(const AllocatorDispatch*, void* address, void* context) {
-  __libc_free(address);
+#if defined(OS_AIX)
+  return free(address);
+#else
+  return __libc_free(address);
+#endif
 }
 
 size_t GlibcGetSizeEstimate(const AllocatorDispatch*,
                             void* address,
                             void* context) {
   // TODO(siggi, primiano): malloc_usable_size may need redirection in the
   //     presence of interposing shims that divert allocations.
+#if defined(OS_AIX)
+  return 0;
+#else
   return malloc_usable_size(address);
+#endif
 }
 
 }  // namespace
 
 const AllocatorDispatch AllocatorDispatch::default_dispatch = {
     &GlibcMalloc,          /* alloc_function */
     &GlibcCalloc,          /* alloc_zero_initialized_function */
     &GlibcMemalign,        /* alloc_aligned_function */
     &GlibcRealloc,         /* realloc_function */
     &GlibcFree,            /* free_function */
     &GlibcGetSizeEstimate, /* get_size_estimate_function */
     nullptr,               /* batch_malloc_function */
     nullptr,               /* batch_free_function */
     nullptr,               /* free_definite_size_function */
     nullptr,               /* next */
 };