runtime: mark some C globals as having no pointers.

C globals are conservatively scanned.  This helps
avoid false retention, especially for 32 bit.

LGTM=rsc
R=golang-codereviews, khr, rsc
CC=golang-codereviews
https://golang.org/cl/102040043

11 files changed, 16 insertions, 0 deletions

diff --git a/src/pkg/runtime/alg.goc b/src/pkg/runtime/alg.goc
index 9fb54cac3f..f1b8d5982b 100644
--- a/src/pkg/runtime/alg.goc
+++ b/src/pkg/runtime/alg.goc
@@ -465,6 +465,7 @@ runtime·algarray[] =
 // Runtime helpers.
 
 // used in asm_{386,amd64}.s
+#pragma dataflag NOPTR
 byte runtime·aeskeysched[HashRandomBytes];
 
 void
diff --git a/src/pkg/runtime/heapdump.c b/src/pkg/runtime/heapdump.c
index 0799a102c4..744c59f9bc 100644
--- a/src/pkg/runtime/heapdump.c
+++ b/src/pkg/runtime/heapdump.c
@@ -17,6 +17,7 @@
 #include "typekind.h"
 #include "funcdata.h"
 #include "zaexperiment.h"
+#include "../../cmd/ld/textflag.h"
 
 extern byte data[];
 extern byte edata[];
@@ -67,6 +68,7 @@ static uintptr dumpfd;
 enum {
 	BufSize = 4096,
 };
+#pragma dataflag NOPTR
 static byte buf[BufSize];
 static uintptr nbuf;
 
diff --git a/src/pkg/runtime/malloc.goc b/src/pkg/runtime/malloc.goc
index 6e1068d93d..7b7e350d8d 100644
--- a/src/pkg/runtime/malloc.goc
+++ b/src/pkg/runtime/malloc.goc
@@ -19,6 +19,7 @@ package runtime
 // Mark mheap as 'no pointers', it does not contain interesting pointers but occupies ~45K.
 #pragma dataflag NOPTR
 MHeap runtime·mheap;
+#pragma dataflag NOPTR
 MStats mstats;
 
 int32	runtime·checking;
diff --git a/src/pkg/runtime/msize.c b/src/pkg/runtime/msize.c
index 63d5ef490e..2fbd5e1042 100644
--- a/src/pkg/runtime/msize.c
+++ b/src/pkg/runtime/msize.c
@@ -28,8 +28,11 @@
 #include "runtime.h"
 #include "arch_GOARCH.h"
 #include "malloc.h"
+#include "../../cmd/ld/textflag.h"
 
+#pragma dataflag NOPTR
 int32 runtime·class_to_size[NumSizeClasses];
+#pragma dataflag NOPTR
 int32 runtime·class_to_allocnpages[NumSizeClasses];
 
 // The SizeToClass lookup is implemented using two arrays,
@@ -41,7 +44,9 @@ int32 runtime·class_to_allocnpages[NumSizeClasses];
 // size divided by 128 (rounded up).  The arrays are filled in
 // by InitSizes.
 
+#pragma dataflag NOPTR
 int8 runtime·size_to_class8[1024/8 + 1];
+#pragma dataflag NOPTR
 int8 runtime·size_to_class128[(MaxSmallSize-1024)/128 + 1];
 
 void runtime·testdefersizes(void);
diff --git a/src/pkg/runtime/os_darwin.c b/src/pkg/runtime/os_darwin.c
index a1165dd7be..33a2df958f 100644
--- a/src/pkg/runtime/os_darwin.c
+++ b/src/pkg/runtime/os_darwin.c
@@ -59,6 +59,7 @@ runtime·osinit(void)
 void
 runtime·get_random_data(byte **rnd, int32 *rnd_len)
 {
+	#pragma dataflag NOPTR
 	static byte urandom_data[HashRandomBytes];
 	int32 fd;
 	fd = runtime·open("/dev/urandom", 0 /* O_RDONLY */, 0);
diff --git a/src/pkg/runtime/os_dragonfly.c b/src/pkg/runtime/os_dragonfly.c
index 35a7de96fe..e7fd2cc06f 100644
--- a/src/pkg/runtime/os_dragonfly.c
+++ b/src/pkg/runtime/os_dragonfly.c
@@ -122,6 +122,7 @@ runtime·osinit(void)
 void
 runtime·get_random_data(byte **rnd, int32 *rnd_len)
 {
+	#pragma dataflag NOPTR
 	static byte urandom_data[HashRandomBytes];
 	int32 fd;
 	fd = runtime·open("/dev/urandom", 0 /* O_RDONLY */, 0);
diff --git a/src/pkg/runtime/os_freebsd.c b/src/pkg/runtime/os_freebsd.c
index 9a8de4206b..02b13472c8 100644
--- a/src/pkg/runtime/os_freebsd.c
+++ b/src/pkg/runtime/os_freebsd.c
@@ -130,6 +130,7 @@ runtime·osinit(void)
 void
 runtime·get_random_data(byte **rnd, int32 *rnd_len)
 {
+	#pragma dataflag NOPTR
 	static byte urandom_data[HashRandomBytes];
 	int32 fd;
 	fd = runtime·open("/dev/urandom", 0 /* O_RDONLY */, 0);
diff --git a/src/pkg/runtime/os_netbsd.c b/src/pkg/runtime/os_netbsd.c
index 7f4b97271c..93229bffeb 100644
--- a/src/pkg/runtime/os_netbsd.c
+++ b/src/pkg/runtime/os_netbsd.c
@@ -188,6 +188,7 @@ runtime·osinit(void)
 void
 runtime·get_random_data(byte **rnd, int32 *rnd_len)
 {
+	#pragma dataflag NOPTR
 	static byte urandom_data[HashRandomBytes];
 	int32 fd;
 	fd = runtime·open("/dev/urandom", 0 /* O_RDONLY */, 0);
diff --git a/src/pkg/runtime/os_openbsd.c b/src/pkg/runtime/os_openbsd.c
index 0eec7956cf..08a290a055 100644
--- a/src/pkg/runtime/os_openbsd.c
+++ b/src/pkg/runtime/os_openbsd.c
@@ -167,6 +167,7 @@ runtime·osinit(void)
 void
 runtime·get_random_data(byte **rnd, int32 *rnd_len)
 {
+	#pragma dataflag NOPTR
 	static byte urandom_data[HashRandomBytes];
 	int32 fd;
 	fd = runtime·open("/dev/urandom", 0 /* O_RDONLY */, 0);
diff --git a/src/pkg/runtime/os_solaris.c b/src/pkg/runtime/os_solaris.c
index 75e7c18f4f..c6bbea3116 100644
--- a/src/pkg/runtime/os_solaris.c
+++ b/src/pkg/runtime/os_solaris.c
@@ -161,6 +161,7 @@ runtime·newosproc(M *mp, void *stk)
 void
 runtime·get_random_data(byte **rnd, int32 *rnd_len)
 {
+	#pragma dataflag NOPTR
 	static byte urandom_data[HashRandomBytes];
 	int32 fd;
 	fd = runtime·open("/dev/urandom", 0 /* O_RDONLY */, 0);
diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index 665d34a40e..da2e0f9fa4 100644
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -2597,6 +2597,7 @@ struct Pdesc
 	uint32	syscalltick;
 	int64	syscallwhen;
 };
+#pragma dataflag NOPTR
 static Pdesc pdesc[MaxGomaxprocs];
 
 static uint32