Re: GCC Go Patch to conditionalize use of sys/mman.h methods

[Ian Lance Taylor <iant at google dot com>]

Joel Sherrill <joel.sherrill@OARcorp.com> writes:

> In trying to compile Go to target RTEMS, we needed to
> address the unconditional use of methods in sys/mman.h.
> You will need to regenerate configure.

Thanks for the patch.  I committed a slightly different patch, as
follows.

Ian

diff -r be2b836f2bd3 libgo/configure.ac
--- a/libgo/configure.ac	Wed Mar 10 14:52:12 2010 -0800
+++ b/libgo/configure.ac	Wed Apr 07 15:19:40 2010 -0700
@@ -181,6 +181,7 @@
 
 AC_C_BIGENDIAN
 
+AC_CHECK_HEADERS(sys/mman.h)
 AC_CACHE_SAVE
 
 if test ${multilib} = yes; then
diff -r be2b836f2bd3 libgo/runtime/go-trampoline.c
--- a/libgo/runtime/go-trampoline.c	Wed Mar 10 14:52:12 2010 -0800
+++ b/libgo/runtime/go-trampoline.c	Wed Apr 07 15:19:40 2010 -0700
@@ -4,11 +4,16 @@
    Use of this source code is governed by a BSD-style
    license that can be found in the LICENSE file.  */
 
+#include "config.h"
+
 #include <assert.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <unistd.h>
+
+#ifdef HAVE_SYS_MMAN_H
 #include <sys/mman.h>
+#endif
 
 #include "go-alloc.h"
 
@@ -21,14 +26,20 @@
 {
   unsigned int page_size;
   void *ret;
-  int i;
 
   page_size = getpagesize ();
   assert (page_size >= size);
   ret = __go_alloc (2 * page_size - 1);
   ret = (void *) (((uintptr_t) ret + page_size - 1)
 		  & ~ ((uintptr_t) page_size - 1));
-  i = mprotect (ret, size, PROT_READ | PROT_WRITE | PROT_EXEC);
-  assert (i == 0);
+
+#ifdef HAVE_SYS_MMAN_H
+  {
+    int i;
+    i = mprotect (ret, size, PROT_READ | PROT_WRITE | PROT_EXEC);
+    assert (i == 0);
+  }
+#endif
+
   return ret;
 }
diff -r be2b836f2bd3 libgo/runtime/mem.c
--- a/libgo/runtime/mem.c	Wed Mar 10 14:52:12 2010 -0800
+++ b/libgo/runtime/mem.c	Wed Apr 07 15:19:40 2010 -0700
@@ -1,4 +1,5 @@
 #include <errno.h>
+
 #include "runtime.h"
 #include "malloc.h"
 
@@ -9,12 +10,12 @@
 
 	mstats.sys += n;
 	p = runtime_mmap(nil, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, -1, 0);
-	if(p < (void*)4096) {
-		if(p == (void*)EACCES) {
+	if (p == MAP_FAILED) {
+		if(errno == EACCES) {
 			printf("mmap: access denied\n");
 			printf("If you're running SELinux, enable execmem for this process.\n");
 		} else {
-			printf("mmap: errno=%p\n", p);
+			printf("mmap: errno=%d\n", errno);
 		}
 		exit(2);
 	}
diff -r be2b836f2bd3 libgo/runtime/runtime.h
--- a/libgo/runtime/runtime.h	Wed Mar 10 14:52:12 2010 -0800
+++ b/libgo/runtime/runtime.h	Wed Apr 07 15:19:40 2010 -0700
@@ -4,13 +4,18 @@
    Use of this source code is governed by a BSD-style
    license that can be found in the LICENSE file.  */
 
+#include "config.h"
+
 #define _GNU_SOURCE
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <pthread.h>
+
+#ifdef HAVE_SYS_MMAN_H
 #include <sys/mman.h>
+#endif
 
 #include "go-alloc.h"
 #include "go-panic.h"
@@ -108,9 +113,15 @@
 
 /* Functions.  */
 #define runtime_memclr(buf, size) __builtin_memset(buf, 0, size)
-#define runtime_mmap mmap
 MCache*	allocmcache(void);
 void	free(void *v);
 void	addfinalizer(void*, void(*fn)(void*), int32);
 
+#ifdef HAVE_SYS_MMAN_H
+#define runtime_mmap mmap
+#else
+#define runtime_mmap(start, len, prot, flags, fd, offset) malloc(len)
+#define MAP_FAILED NULL
+#endif
+
 #define cas(pval, old, new) __sync_bool_compare_and_swap (pval, old, new)