Changeset 160213 in webkit

Timestamp:

Dec 5, 2013 9:32:06 PM (10 years ago)

Author:

msaboff@apple.com

Message:

JSC: Simplify interface between throw and catch handler
​https://bugs.webkit.org/show_bug.cgi?id=125328

Reviewed by Geoffrey Garen.

Simplified the throw - catch interface. The throw side is only responsible for
jumping to the appropriate op_catch handler or returnFromJavaScript for uncaught
exceptions. The handler uses the exception values like VM.callFrameForThrow
as appropriate and no longer relies on the throw side putting anything in
registers.

• jit/CCallHelpers.h:

(JSC::CCallHelpers::jumpToExceptionHandler):

• jit/JITOpcodes.cpp:

(JSC::JIT::emit_op_catch):

• jit/JITOpcodes32_64.cpp:

(JSC::JIT::emit_op_catch):

• llint/LowLevelInterpreter32_64.asm:

(_llint_op_catch):
(_llint_throw_from_slow_path_trampoline):

• llint/LowLevelInterpreter64.asm:

(_llint_op_catch):
(_llint_throw_from_slow_path_trampoline):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• jit/CCallHelpers.h (modified) (1 diff)
• jit/JITOpcodes.cpp (modified) (1 diff)
• jit/JITOpcodes32_64.cpp (modified) (1 diff)
• llint/LowLevelInterpreter32_64.asm (modified) (2 diffs)
• llint/LowLevelInterpreter64.asm (modified) (2 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2013-12-05  Michael Saboff  <msaboff@apple.com>
+
+        JSC: Simplify interface between throw and catch handler
+        https://bugs.webkit.org/show_bug.cgi?id=125328
+
+        Reviewed by Geoffrey Garen.
+
+        Simplified the throw - catch interface.  The throw side is only responsible for
+        jumping to the appropriate op_catch handler or returnFromJavaScript for uncaught
+        exceptions.  The handler uses the exception values like VM.callFrameForThrow
+        as appropriate and no longer relies on the throw side putting anything in
+        registers.
+
+        * jit/CCallHelpers.h:
+        (JSC::CCallHelpers::jumpToExceptionHandler):
+        * jit/JITOpcodes.cpp:
+        (JSC::JIT::emit_op_catch):
+        * jit/JITOpcodes32_64.cpp:
+        (JSC::JIT::emit_op_catch):
+        * llint/LowLevelInterpreter32_64.asm:
+        (_llint_op_catch):
+        (_llint_throw_from_slow_path_trampoline):
+        * llint/LowLevelInterpreter64.asm:
+        (_llint_op_catch):
+        (_llint_throw_from_slow_path_trampoline):
+
 2013-12-04  Oliver Hunt  <oliver@apple.com>
 

trunk/Source/JavaScriptCore/jit/CCallHelpers.h

@@ -1575 +1575 @@
         // genericUnwind() leaves the handler CallFrame* in vm->callFrameForThrow,
         // and the address of the handler in vm->targetMachinePCForThrow.
-        // The exception handler expects the CallFrame* in regT0.
-        move(TrustedImmPtr(vm()), GPRInfo::regT0);
-        loadPtr(Address(GPRInfo::regT0, VM::targetMachinePCForThrowOffset()), GPRInfo::regT1);
-        loadPtr(Address(GPRInfo::regT0, VM::callFrameForThrowOffset()), GPRInfo::regT0);
+        loadPtr(&vm()->targetMachinePCForThrow, GPRInfo::regT1);
         jump(GPRInfo::regT1);
     }

trunk/Source/JavaScriptCore/jit/JITOpcodes.cpp

@@ -649 +649 @@
 void JIT::emit_op_catch(Instruction* currentInstruction)
 {
-    move(regT0, callFrameRegister);
     move(TrustedImmPtr(m_vm), regT3);
+    load64(Address(regT3, VM::callFrameForThrowOffset()), callFrameRegister);
     load64(Address(regT3, VM::exceptionOffset()), regT0);
     store64(TrustedImm64(JSValue::encode(JSValue())), Address(regT3, VM::exceptionOffset()));

trunk/Source/JavaScriptCore/jit/JITOpcodes32_64.cpp

@@ -925 +925 @@
 void JIT::emit_op_catch(Instruction* currentInstruction)
 {
+    move(TrustedImmPtr(m_vm), regT3);
     // operationThrow returns the callFrame for the handler.
-    move(regT0, callFrameRegister);
-
+    load32(Address(regT3, VM::callFrameForThrowOffset()), callFrameRegister);
     // Now store the exception returned by operationThrow.
-    move(TrustedImmPtr(m_vm), regT3);
     load32(Address(regT3, VM::exceptionOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.payload)), regT0);
     load32(Address(regT3, VM::exceptionOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.tag)), regT1);

trunk/Source/JavaScriptCore/llint/LowLevelInterpreter32_64.asm

@@ -1981 +1981 @@
     # machine code return address will be set to _llint_op_catch), and from
     # the interpreter's throw trampoline (see _llint_throw_trampoline).
-    # The JIT throwing protocol calls for the cfr to be in t0. The throwing
-    # code must have known that we were throwing to the interpreter, and have
-    # set VM::targetInterpreterPCForThrow.
-    move t0, cfr
+    # The throwing code must have known that we were throwing to the interpreter,
+    # and have set VM::targetInterpreterPCForThrow.
     loadp CodeBlock[cfr], t3
     loadp CodeBlock::m_vm[t3], t3
+    loadp VM::callFrameForThrow[t3], cfr
     loadi VM::targetInterpreterPCForThrow[t3], PC
     loadi VM::m_exception + PayloadOffset[t3], t0
@@ -2051 +2050 @@
     loadp CodeBlock[cfr], t1
     loadp CodeBlock::m_vm[t1], t1
-    loadp VM::topCallFrame[t1], cfr
-    loadp VM::callFrameForThrow[t1], t0
     jmp VM::targetMachinePCForThrow[t1]
 

trunk/Source/JavaScriptCore/llint/LowLevelInterpreter64.asm

@@ -1784 +1784 @@
     # machine code return address will be set to _llint_op_catch), and from
     # the interpreter's throw trampoline (see _llint_throw_trampoline).
-    # The JIT throwing protocol calls for the cfr to be in t0. The throwing
-    # code must have known that we were throwing to the interpreter, and have
-    # set VM::targetInterpreterPCForThrow.
-    move t0, cfr
+    # The throwing code must have known that we were throwing to the interpreter,
+    # and have set VM::targetInterpreterPCForThrow.
+    loadp CodeBlock[cfr], t3
+    loadp CodeBlock::m_vm[t3], t3
+    loadp VM::callFrameForThrow[t3], cfr
     loadp CodeBlock[cfr], PB
     loadp CodeBlock::m_instructions[PB], PB
-    loadp CodeBlock[cfr], t3
-    loadp CodeBlock::m_vm[t3], t3
     loadp VM::targetInterpreterPCForThrow[t3], PC
     subp PB, PC
@@ -1820 +1819 @@
     loadp CodeBlock[cfr], t1
     loadp CodeBlock::m_vm[t1], t1
-    loadp VM::topCallFrame[t1], cfr
-    loadp VM::callFrameForThrow[t1], t0
     jmp VM::targetMachinePCForThrow[t1]