commit 2a9413710c94405d35722b4134532f1ae1e87b42
author Ben Cheng <bccheng@android.com> Tue Mar 09 22:32:03 2010 -0800
committer Ben Cheng <bccheng@android.com> Tue Mar 09 22:32:03 2010 -0800
tree f3dce0b96867975ab52b5d722d7a548fca4311ec
parent 699c9eb5630d4016a984f5b501a7171848e8daa9

Align fake data in the same page offsets as those in the bugreport.

Sometimes the crash in the JIT'ed code is due to CPU bugs which are sensitive
to placement of the code.

Change-Id: I017ec3620f8172e2fac9e7abfa07f76b65db2306

tools/gdbjithelper/gdbjithelper.c

diff --git a/tools/gdbjithelper/gdbjithelper.c b/tools/gdbjithelper/gdbjithelper.c
index d0f9ce3..862fcae 100644
--- a/tools/gdbjithelper/gdbjithelper.c
+++ b/tools/gdbjithelper/gdbjithelper.c
@@ -16,6 +16,11 @@
 
 #include <unistd.h>
 #include <stdio.h>
+#include <malloc.h>
+#include <string.h>
+
+/* Currently debuggerd dumps 20 words each around PC and LR */
+#define NUM_DUMPED_WORDS 20
 
 volatile int done;
 
@@ -63,22 +68,39 @@
     0x4284aa7a, 0xf927f7b7, 0x40112268, 0x419da7f8,
 };
 
-void dumpCode()
+/* For example: 463ba1e4 & 0xfff */
+#define START_PC_PAGE_OFFSET 0x1e4
+
+/* For example: 463ba1a8 & 0xfff */
+#define START_LR_PAGE_OFFSET 0x1a8
+
+/* Each points to a two-page buffer */
+char *codePCCache, *codeLRCache;
+
+void dumpCode(int *pc, int *lr)
 {
     unsigned int i;
 
-    for (i = 0; i < sizeof(codePC)/sizeof(int); i++) {
-        printf("codePC[%d]: %#x\n", i, codePC[i]);
+    for (i = 0; i < NUM_DUMPED_WORDS; i++) {
+        printf("%p codePC[%d]: %#010x\n", pc + i, i, pc[i]);
     }
 
-    for (i = 0; i < sizeof(codeLR)/sizeof(int); i++) {
-        printf("codeLR[%d]: %#x\n", i, codeLR[i]);
+    for (i = 0; i < NUM_DUMPED_WORDS; i++) {
+        printf("%p codeLR[%d]: %#010x\n", lr + i, i, lr[i]);
     }
 }
 
 int main()
 {
-    dumpCode();
+    codePCCache = memalign(4096, 8192);
+    codeLRCache = memalign(4096, 8192);
+
+    memcpy(codePCCache + START_PC_PAGE_OFFSET, codePC, 4 * NUM_DUMPED_WORDS);
+    memcpy(codeLRCache + START_LR_PAGE_OFFSET, codeLR, 4 * NUM_DUMPED_WORDS);
+
+    dumpCode((int *) (codePCCache + START_PC_PAGE_OFFSET),
+             (int *) (codeLRCache + START_LR_PAGE_OFFSET));
+
     while (!done) {
         sleep(1000);
     }