Changeset 44514 in webkit for trunk/JavaScriptCore/assembler/AbstractMacroAssembler.h

Timestamp:

Jun 8, 2009, 6:40:59 PM (16 years ago)

Author:

[email protected]

Message:

2009-06-08 Gavin Barraclough <​[email protected]>

Reviewed by Geoff Garen.

Add (incomplete) support to YARR for running with the jit enabled
on Arm thumb2 platforms. Adds new Assembler/MacroAssembler classes,
along with cache flushing support, tweaks to MacroAssemblerCodePtr
to support decorated thumb code pointers, and new enter/exit code
to YARR jit for the platform.

Support for this platform is still under development - the assembler
currrently only supports planting and linking jumps with a 16Mb range.
As such, initially commiting in a disabled state.

• JavaScriptCore.xcodeproj/project.pbxproj:

Add new assembler files.

• assembler/ARMv7Assembler.h: Added.

Add new Assembler.

• assembler/AbstractMacroAssembler.h:

Tweaks to ensure sizes of pointer values planted in JIT code do not change.

• assembler/MacroAssembler.h:

On ARMv7 platforms use MacroAssemblerARMv7.

• assembler/MacroAssemblerARMv7.h: Added.

Add new MacroAssembler.

• assembler/MacroAssemblerCodeRef.h: (JSC::FunctionPtr::FunctionPtr):

Add better ASSERT.

(JSC::ReturnAddressPtr::ReturnAddressPtr):

Add better ASSERT.

(JSC::MacroAssemblerCodePtr::MacroAssemblerCodePtr):

On ARMv7, MacroAssemblerCodePtr's mush be 'decorated' with a low bit set,
to indicate to the processor that the code is thumb code, not traditional
32-bit ARM.

(JSC::MacroAssemblerCodePtr::dataLocation):

On ARMv7, decoration must be removed.

• jit/ExecutableAllocator.h: (JSC::ExecutableAllocator::makeWritable):

Reformatted, no change.

(JSC::ExecutableAllocator::makeExecutable):

When marking code executable also cache flush it, where necessary.

(JSC::ExecutableAllocator::MakeWritable::MakeWritable):

Only use the null implementation of this class if both !ASSEMBLER_WX_EXCLUSIVE
and running on x86(_64) - on other platforms we may also need ensure that
makeExecutable is called at the end to flush caches.

(JSC::ExecutableAllocator::reprotectRegion):

Reformatted, no change.

(JSC::ExecutableAllocator::cacheFlush):

Cache flush a region of memory, or platforms where this is necessary.

• wtf/Platform.h:

Add changes necessary to allow YARR jit to build on this platform, disabled.

• yarr/RegexJIT.cpp: (JSC::Yarr::RegexGenerator::generateEnter): (JSC::Yarr::RegexGenerator::generateReturn):

Add support to these methods for ARMv7.

File:

• trunk/JavaScriptCore/assembler/AbstractMacroAssembler.h (modified) (5 diffs)

trunk/JavaScriptCore/assembler/AbstractMacroAssembler.h

@@ -182 +182 @@
         explicit Imm32(int32_t value)
             : m_value(value)
+#if PLATFORM(ARM_V7)
+            , m_isPointer(false)
+#endif
         {
         }
@@ -188 +191 @@
         explicit Imm32(ImmPtr ptr)
             : m_value(ptr.asIntptr())
-        {
-        }
+#if PLATFORM(ARM_V7)
+            , m_isPointer(true)
 #endif
+        {
+        }
+#endif
 
         int32_t m_value;
+#if PLATFORM(ARM_V7)
+        // We rely on being able to regenerate code to recover exception handling
+        // information.  Since ARMv7 supports 16-bit immediates there is a danger
+        // that if pointer values change the layout of the generated code will change.
+        // To avoid this problem, always generate pointers (and thus Imm32s constructed
+        // from ImmPtrs) with a code sequence that is able  to represent  any pointer
+        // value - don't use a more compact form in these cases.
+        bool m_isPointer;
+#endif
     };
 
@@ -529 +544 @@
         void relink(CodeLocationLabel destination)
         {
-            AssemblerType::relinkJump(this->dataLocation(), destination.executableAddress());
+            AssemblerType::relinkJump(this->dataLocation(), destination.dataLocation());
         }
 
@@ -787 +802 @@
         void link(Jump jump, CodeLocationLabel label)
         {
-            AssemblerType::linkJump(code(), jump.m_jmp, label.executableAddress());
+            AssemblerType::linkJump(code(), jump.m_jmp, label.dataLocation());
         }
 
@@ -793 +808 @@
         {
             for (unsigned i = 0; i < list.m_jumps.size(); ++i)
-                AssemblerType::linkJump(code(), list.m_jumps[i].m_jmp, label.executableAddress());
+                AssemblerType::linkJump(code(), list.m_jumps[i].m_jmp, label.dataLocation());
         }