Use movw/movt instead of constant pool on ARMv7

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index 29cf434285fa61dbfa742adef9f2e6c264e9901e..cec4a3b146d57d7fe1c4710dea8d3bf87cf2e35e 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -108,7 +108,7 @@ void MacroAssembler::Jump(Handle<Code> code, RelocInfo::Mode rmode,
 
 
 int MacroAssembler::CallSize(Register target, Condition cond) {
-#if USE_BLX
+#ifdef USE_BLX
   return kInstrSize;
 #else
   return 2 * kInstrSize;
@@ -121,7 +121,7 @@ void MacroAssembler::Call(Register target, Condition cond) {
   BlockConstPoolScope block_const_pool(this);
   Label start;
   bind(&start);
-#if USE_BLX
+#ifdef USE_BLX
   blx(target, cond);
 #else
   // set lr for return at current pc + 8
@@ -163,10 +163,16 @@ void MacroAssembler::Call(Address target,
   BlockConstPoolScope block_const_pool(this);
   Label start;
   bind(&start);
-#if USE_BLX
-  // On ARMv5 and after the recommended call sequence is:
-  //  ldr ip, [pc, #...]
-  //  blx ip
+#ifdef USE_BLX
+  // Call sequence on V7 or later is :
+  //  movw  ip, #... @ call address low 16
+  //  movt  ip, #... @ call address high 16
+  //  blx   ip
+  //                      @ return address
+  // Or pre-V7:
+  //  ldr   ip, [pc, #...] @ call address
+  //  blx   ip
+  //                      @ return address
 
   // Statement positions are expected to be recorded when the target
   // address is loaded. The mov method will automatically record
@@ -176,14 +182,11 @@ void MacroAssembler::Call(Address target,
 
   mov(ip, Operand(reinterpret_cast<int32_t>(target), rmode));
   blx(ip, cond);
-
-  ASSERT(kCallTargetAddressOffset == 2 * kInstrSize);
 #else
   // Set lr for return at current pc + 8.
   mov(lr, Operand(pc), LeaveCC, cond);
   // Emit a ldr<cond> pc, [pc + offset of target in constant pool].
   mov(pc, Operand(reinterpret_cast<int32_t>(target), rmode), LeaveCC, cond);
-  ASSERT(kCallTargetAddressOffset == kInstrSize);
 #endif
   ASSERT_EQ(CallSize(target, rmode, cond), SizeOfCodeGeneratedSince(&start));
 }
@@ -288,17 +291,15 @@ void MacroAssembler::Move(DoubleRegister dst, DoubleRegister src) {
 void MacroAssembler::And(Register dst, Register src1, const Operand& src2,
                          Condition cond) {
   if (!src2.is_reg() &&
-      !src2.must_use_constant_pool(this) &&
+      !src2.must_output_reloc_info(this) &&
       src2.immediate() == 0) {
     mov(dst, Operand(0, RelocInfo::NONE), LeaveCC, cond);
-
   } else if (!src2.is_single_instruction(this) &&
-             !src2.must_use_constant_pool(this) &&
+             !src2.must_output_reloc_info(this) &&
              CpuFeatures::IsSupported(ARMv7) &&
              IsPowerOf2(src2.immediate() + 1)) {

[Please use jfb - chromium.org, 2012/10/10 13:56:52]

It would be kind of silly, but if src2 == 0xffffffff then this is undefined. In
that case it should just be a MVN Rd, 0, which can be handled before this
else_if.

[danno, 2012/10/17 10:04:44]

Possible, but that's for a separate CL.
On 2012/10/10 13:56:52, jfb wrote:

     ubfx(dst, src1, 0,
         WhichPowerOf2(static_cast<uint32_t>(src2.immediate()) + 1), cond);
-
   } else {
     and_(dst, src1, src2, LeaveCC, cond);
   }