Changeset 287301 in webkit for trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h

Timestamp:

Dec 21, 2021, 12:33:18 AM (3 years ago)

Author:

[email protected]

Message:

[JSC][ARMv7] Minor code size improvements
​https://bugs.webkit.org/show_bug.cgi?id=234387

Patch by Geza Lore <Geza Lore> on 2021-12-21
Reviewed by Yusuke Suzuki.

A few mew code size improvements to ARMv7/Thumb-2

• Use ldrd/strd in mode places (via AssemblyHelpers:loadValue

and AssemblyHelpers::storeValue)

• Use BIC immediate instruction instead of AND where appropriate

• Use a 2-byte ADDS instead of a 4-byte CMN when possible. This

applies very often as it handles testing JSValue tags.

• Use addressTempRegister in branch32

Overall saving of about 3.5% code size on JetStream2, according to
--dumpLinkBufferStats.

• assembler/ARMv7Assembler.h:

(JSC::ARMv7Assembler::bic):

• assembler/MacroAssemblerARMv7.h:

(JSC::MacroAssemblerARMv7::and32):
(JSC::MacroAssemblerARMv7::storePair32):
(JSC::MacroAssemblerARMv7::compare32AndSetFlags):
(JSC::MacroAssemblerARMv7::branch32):

• assembler/MacroAssemblerMIPS.h:

(JSC::MacroAssemblerMIPS::storePair32):

• bytecode/AccessCase.cpp:

(JSC::AccessCase::generateImpl):

• dfg/DFGOSRExit.cpp:

(JSC::DFG::OSRExit::compileExit):

• dfg/DFGSpeculativeJIT32_64.cpp:

(JSC::DFG::SpeculativeJIT::fillJSValue):
(JSC::DFG::SpeculativeJIT::emitCall):
(JSC::DFG::SpeculativeJIT::compileGetByVal):
(JSC::DFG::SpeculativeJIT::compile):

• jit/AssemblyHelpers.h:

(JSC::AssemblyHelpers::storeValue):

• jit/JITOpcodes.cpp:

(JSC::JIT::emit_op_mov):

File:

• trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h (modified) (4 diffs)

trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h

@@ -280 +280 @@
     {
         ARMThumbImmediate armImm = ARMThumbImmediate::makeEncodedImm(imm.m_value);
-        if (armImm.isValid())
+        if (armImm.isValid()) {
             m_assembler.ARM_and(dest, src, armImm);
-        else {
-            move(imm, dataTempRegister);
-            m_assembler.ARM_and(dest, src, dataTempRegister);
-        }
+            return;
+        }
+
+        armImm = ARMThumbImmediate::makeEncodedImm(~imm.m_value);
+        if (armImm.isValid()) {
+            m_assembler.bic(dest, src, armImm);
+            return;
+        }
+
+        move(imm, dataTempRegister);
+        m_assembler.ARM_and(dest, src, dataTempRegister);
     }
 
@@ -1025 +1032 @@
         }
         storePair32(src1, src2, Address(dataTempRegister, address.offset));
+    }
+
+    void storePair32(RegisterID src1, RegisterID src2, const void* address)
+    {
+        move(TrustedImmPtr(address), addressTempRegister);
+        storePair32(src1, src2, addressTempRegister);
     }
 
@@ -1588 +1601 @@
         int32_t imm = right.m_value;
         ARMThumbImmediate armImm = ARMThumbImmediate::makeEncodedImm(imm);
-        if (armImm.isValid())
+        if (armImm.isValid()) {
             m_assembler.cmp(left, armImm);
-        else if ((armImm = ARMThumbImmediate::makeEncodedImm(-imm)).isValid())
+            return;
+        }
+
+        armImm = ARMThumbImmediate::makeEncodedImm(-imm);
+        if (armImm.isValid()) {
+            if (!(left & 8) && armImm.isUInt3() && (left != addressTempRegister)) {
+                // This is common enough to warrant a special case to save 2 bytes
+                m_assembler.add_S(addressTempRegister, left, armImm);
+                return;
+            }
             m_assembler.cmn(left, armImm);
-        else {
-            RegisterID scratch = bestTempRegister(left);
-            move(TrustedImm32(imm), scratch);
-            m_assembler.cmp(left, scratch);
-        }
+            return;
+        }
+
+        RegisterID scratch = bestTempRegister(left);
+        move(TrustedImm32(imm), scratch);
+        m_assembler.cmp(left, scratch);
     }
 
@@ -1680 +1703 @@
     {
         if (left == ARMRegisters::sp) {
-            move(left, dataTempRegister);
-            m_assembler.cmp(dataTempRegister, right);
+            move(left, addressTempRegister);
+            m_assembler.cmp(addressTempRegister, right);
         } else if (right == ARMRegisters::sp) {
-            move(right, dataTempRegister);
-            m_assembler.cmp(left, dataTempRegister);
+            move(right, addressTempRegister);
+            m_assembler.cmp(left, addressTempRegister);
         } else
             m_assembler.cmp(left, right);