Changeset 166732 in webkit

Timestamp:

Apr 3, 2014 11:25:26 AM (10 years ago)

Author:

mark.lam@apple.com

Message:

Fix bit rot in ARMv7 JIT probe mechanism.
<​https://webkit.org/b/131167>

Reviewed by Geoffrey Garen.

1. The macro assembler does not support pushing the SP register. Worked around this by pushing the LR register as a placeholder, and then writing the original SP value to that slot.
2. The CPUState field in the ProbeContext needs to be aligned on a 4 byte boundary, not an 8 byte boundary.

• assembler/MacroAssemblerARMv7.cpp:

(JSC::MacroAssemblerARMv7::probe):

• jit/JITStubsARMv7.h:

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• assembler/MacroAssemblerARMv7.cpp (modified) (1 diff)
• jit/JITStubsARMv7.h (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2014-04-03  Mark Lam  <mark.lam@apple.com>
+
+        Fix bit rot in ARMv7 JIT probe mechanism.
+        <https://webkit.org/b/131167>
+
+        Reviewed by Geoffrey Garen.
+
+        1. The macro assembler does not support pushing the SP register.  Worked
+           around this by pushing the LR register as a placeholder, and then
+           writing the original SP value to that slot.
+        2. The CPUState field in the ProbeContext needs to be aligned on a 4
+           byte boundary, not an 8 byte boundary.
+
+        * assembler/MacroAssemblerARMv7.cpp:
+        (JSC::MacroAssemblerARMv7::probe):
+        * jit/JITStubsARMv7.h:
+
 2014-04-02  Mark Lam  <mark.lam@apple.com>
 

trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.cpp

@@ -83 +83 @@
 void MacroAssemblerARMv7::probe(MacroAssemblerARMv7::ProbeFunction function, void* arg1, void* arg2)
 {
-    push(RegisterID::sp);
     push(RegisterID::lr);
+    push(RegisterID::lr);
+    add32(TrustedImm32(8), RegisterID::sp, RegisterID::lr);
+    store32(RegisterID::lr, ArmAddress(RegisterID::sp, 4));
     push(RegisterID::ip);
     push(RegisterID::r0);

trunk/Source/JavaScriptCore/jit/JITStubsARMv7.h

@@ -53 +53 @@
 #define PROBE_ARG2_OFFSET (2 * PTR_SIZE)
 
-#define PROBE_FIRST_GPREG_OFFSET (4 * PTR_SIZE)
+#define PROBE_FIRST_GPREG_OFFSET (3 * PTR_SIZE)
 
 #define GPREG_SIZE 4