Modify the NaCl_page_alloc_hint function to use VirtualQuery to check

src/trusted/service_runtime/arch/x86_32/sel_addrspace_x86_32.c

Index: src/trusted/service_runtime/arch/x86_32/sel_addrspace_x86_32.c
===================================================================
--- src/trusted/service_runtime/arch/x86_32/sel_addrspace_x86_32.c	(revision 6420)
+++ src/trusted/service_runtime/arch/x86_32/sel_addrspace_x86_32.c	(working copy)
@@ -9,9 +9,9 @@
 #include "native_client/src/trusted/service_runtime/sel_memory.h"
 #include "native_client/src/trusted/service_runtime/sel_ldr.h"
 
-
 NaClErrorCode NaClAllocateSpace(void **mem, size_t addrsp_size) {
   int result;
+  const size_t kOneGb = 0x40000000;

[Brad Chen, 2011/08/16 01:21:49]

I'm used to 'b' meaning 'bit'. I'd rather see kOneGB here. Some folks find (1 <<
30) more readable than 0x40000000; your call.

[bbudge, 2011/08/16 19:46:22]

Done.

 
   CHECK(NULL != mem);
 
@@ -26,6 +26,16 @@
   *mem = (void *) NACL_TRAMPOLINE_START;
   result = NaCl_page_alloc_at_addr(mem, addrsp_size);
   *mem = 0;
+#elif NACL_WINDOWS && NACL_ARCH_CPU_32_BITS

[Mark Seaborn, 2011/08/16 17:34:10]

Can you use "NACL_BUILD_SUBARCH == 64" rather than "NACL_ARCH_CPU_32_BITS", for
consistency?  No-one is using the latter.

[bbudge, 2011/08/16 19:46:22]

Done.

+  /*
+   * On 32 bit Windows XP, a 1Gb region of address space is reserved before
+   * starting up this process to make sure we can get a contiguous block. Look
+   * for it now.
+   */
+  if (0 == NaCl_find_sandbox_memory(mem, kOneGb))

[Mark Seaborn, 2011/08/16 17:34:10]

Nit: I'd use curly brackets for this 'if'.

[bbudge, 2011/08/16 19:46:22]

Done.

+    result = NaCl_page_alloc_at_addr(mem, addrsp_size);

[Brad Chen, 2011/08/16 01:21:49]

I don't understand how mem gets initialized in this case.

[bbudge, 2011/08/16 17:21:02]

It's obscure, but the 'mem' parameter gets filled in by the call to
NaCl_find_sandbox_memory if the pre-reserved region is found. Then the call to
NaCl_page_alloc_at_addr tries to use that address.

[Brad Chen, 2011/08/16 17:28:38]

Nit: A brief comment before the call to NaCl_page_alloc_at_addr might be
helpful.
On 2011/08/16 17:21:02, bbudge1 wrote:

[bbudge, 2011/08/16 19:46:22]

Done. (I expanded the comment for the whole case)

+  else
+    result = NaCl_page_alloc(mem, addrsp_size);
 #else
   result = NaCl_page_alloc(mem, addrsp_size);
 #endif