Changeset 86999 in webkit for trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h

Timestamp:

May 20, 2011, 4:20:48 PM (14 years ago)

Author:

[email protected]

Message:

2011-05-20 Oliver Hunt <​[email protected]>

Reviewed by Gavin Barraclough.

Reduce size of inline cache path of get_by_id on ARMv7
​https://bugs.webkit.org/show_bug.cgi?id=61221

This reduces the code size of get_by_id by 20 bytes

• assembler/ARMv7Assembler.h: (JSC::ARMv7Assembler::ldrCompact): (JSC::ARMv7Assembler::repatchCompact): (JSC::ARMv7Assembler::setUInt7ForLoad):
• assembler/MacroAssemblerARMv7.h: (JSC::MacroAssemblerARMv7::load32WithCompactAddressOffsetPatch):
• jit/JIT.h:

File:

• trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h

@@ -49 +49 @@
     typedef ARMv7Assembler::JumpType JumpType;
     typedef ARMv7Assembler::JumpLinkType JumpLinkType;
-    static const int MaximumCompactPtrAlignedAddressOffset = 0x7FFFFFFF;
+    // Magic number is the biggest useful offset we can get on ARMv7 with
+    // a LDR_imm_T2 encoding
+    static const int MaximumCompactPtrAlignedAddressOffset = 124;
 
     MacroAssemblerARMv7()
@@ -486 +488 @@
     DataLabelCompact load32WithCompactAddressOffsetPatch(Address address, RegisterID dest)
     {
-        DataLabel32 label = load32WithAddressOffsetPatch(address, dest);
-        return DataLabelCompact(label.label());
+        DataLabelCompact label(this);
+        ASSERT(address.offset >= 0);
+        ASSERT(address.offset <= MaximumCompactPtrAlignedAddressOffset);
+        ASSERT(ARMThumbImmediate::makeUInt12(address.offset).isUInt7());
+        m_assembler.ldrCompact(dest, address.base, ARMThumbImmediate::makeUInt12(address.offset));
+        return label;
     }