Bug 1010556 - Bump ASAN kTrustedScriptBuffer constant, to account for the new frame size. r=bholley

js/src/shell/js.cpp

@@ -3208,6 +3208,18 @@ StackDump(JSContext *cx, unsigned argc, Value *vp)
 }
 #endif
 
+static bool
+StackPointerInfo(JSContext *cx, unsigned argc, Value *vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+
+    // Copy the truncated stack pointer to the result.  This value is not used
+    // as a pointer but as a way to measure frame-size from JS.
+    args.rval().setInt32(int32_t(reinterpret_cast<size_t>(&args) & 0xfffffff));
+    return true;
+}
+
+
 static bool
 Elapsed(JSContext *cx, unsigned argc, jsval *vp)
 {
@@ -4897,6 +4909,11 @@ static const JSFunctionSpecWithHelp shell_functions[] = {
 "isLatin1(s)",
 "  Return true iff the string's characters are stored as Latin1."),
 
+    JS_FN_HELP("stackPointerInfo", StackPointerInfo, 0, 0,
+"stackPointerInfo()",
+"  Return an int32 value which corresponds to the offset of the latest stack\n"
+"  pointer, such that one can take the differences of 2 to estimate a frame-size."),
+
     JS_FS_HELP_END
 };
 

js/xpconnect/src/XPCJSRuntime.cpp

@@ -3325,8 +3325,8 @@ XPCJSRuntime::XPCJSRuntime(nsXPConnect* aXPConnect)
     // OSX 64-bit Debug: 7MB stack, 636 stack frames => ~11.3k per stack frame
     // OSX64 Opt: 7MB stack, 2440 stack frames => ~3k per stack frame
     //
-    // Linux 32-bit Debug: 2MB stack, 447 stack frames => ~4.6k per stack frame
-    // Linux 64-bit Debug: 4MB stack, 501 stack frames => ~8.2k per stack frame
+    // Linux 32-bit Debug: 2MB stack, 426 stack frames => ~4.8k per stack frame
+    // Linux 64-bit Debug: 4MB stack, 455 stack frames => ~9.0k per stack frame
     //
     // Windows (Opt+Debug): 900K stack, 235 stack frames => ~3.4k per stack frame
     //
@@ -3358,9 +3358,9 @@ XPCJSRuntime::XPCJSRuntime(nsXPConnect* aXPConnect)
     // were not taken at the time of this writing, so we hazard a guess that
     // ASAN builds have roughly thrice the stack overhead as normal builds.
     // On normal builds, the largest stack frame size we might encounter is
-    // 8.2k, so let's use a buffer of 8.2 * 3 * 10 = 246k.
+    // 9.0k (see above), so let's use a buffer of 9.0 * 3 * 10 = 270k.
     const size_t kStackQuota =  2 * kDefaultStackQuota;
-    const size_t kTrustedScriptBuffer = 246 * 1024;
+    const size_t kTrustedScriptBuffer = 270 * 1024;
 #elif defined(XP_WIN)
     // 1MB is the default stack size on Windows, so use 900k.
     // Windows PGO stack frames have unfortunately gotten pretty large lately. :-(

js/xpconnect/tests/chrome/test_bug732665.xul

@@ -67,6 +67,11 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=732665
   // enough to make the cross-compartment call. So rather than exhausting the
   // stack entirely and then checking for 10 chrome frames, we leave ourselves
   // one frame's worth, and check for 11.
+  //
+  // If this assertion fails, the current work-around so far is to measure
+  // again the worst frame size, by using the JS Shell to run
+  // test_bug732665_meta.js . This script will output numbers to update
+  // XPCJSRuntime.cpp comment, as well as the kTrustedScriptBuffer constant.
   contentSb.nnslChrome = chromeSb.nearNativeStackLimit;
   var nestedLimit = Cu.evalInSandbox("nearNativeStackLimit(1, function() { nestedLimit = nnslChrome(0);}); nestedLimit;", contentSb);
   ok(nestedLimit >= 11, "Chrome should be invokable from content script with an exhausted stack: " + nestedLimit);

js/xpconnect/tests/chrome/test_bug732665_meta.js

@@ -0,0 +1,26 @@
+var bottom = stackPointerInfo();
+var top = bottom;
+
+function nearNativeStackLimit() {
+  function inner() {
+    try {
+      with ({}) { // keep things predictable -- stay in the interpreter
+        top = stackPointerInfo();
+        var stepsFromLimit = eval("inner()"); // Use eval to force a number of native stackframes to be created.
+      }
+      return stepsFromLimit + 1;
+    } catch(e) {
+      // It would be nice to check here that the exception is actually an
+      // over-recursion here. But doing so would require toString()ing the
+      // exception, which we may not have the stack space to do.
+      return 1;
+    }
+  }
+  return inner();
+}
+
+var nbFrames = nearNativeStackLimit();
+var frameSize = bottom - top;
+print("Max stack size:", frameSize, "bytes",
+      "\nMaximum number of frames:", nbFrames,
+      "\nAverage frame size:", Math.ceil(frameSize / nbFrames), "bytes");