ARM64: optimize call immediate

src/arm64/macro-assembler-arm64.cc

Index: src/arm64/macro-assembler-arm64.cc
diff --git a/src/arm64/macro-assembler-arm64.cc b/src/arm64/macro-assembler-arm64.cc
index d7d0ab7502308f2687beb126076c70e4e3ca1905..011f5b8e86ecf296d0e6613a863f9cd656fcca4a 100644
--- a/src/arm64/macro-assembler-arm64.cc
+++ b/src/arm64/macro-assembler-arm64.cc
@@ -2024,11 +2024,16 @@ void MacroAssembler::Call(Address target, RelocInfo::Mode rmode) {
   Register temp = temps.AcquireX();
 
   if (rmode == RelocInfo::NONE64) {
+    // Addresses are 48 bits so we never need to load the upper 16 bits.

[ulan, 2014/03/24 12:45:54]

ASSERT_EQ(0, ((imm >> 48) & 0xffff));

     uint64_t imm = reinterpret_cast<uint64_t>(target);
     movz(temp, (imm >> 0) & 0xffff, 0);
-    movk(temp, (imm >> 16) & 0xffff, 16);
-    movk(temp, (imm >> 32) & 0xffff, 32);
-    movk(temp, (imm >> 48) & 0xffff, 48);
+    if (predictable_code_size()) {
+      movk(temp, (imm >> 16) & 0xffff, 16);
+      movk(temp, (imm >> 32) & 0xffff, 32);
+    } else {
+      if (((imm >> 16) & 0xffff) != 0) movk(temp, (imm >> 16) & 0xffff, 16);
+      if (((imm >> 32) & 0xffff) != 0) movk(temp, (imm >> 32) & 0xffff, 32);

[ulan, 2014/03/24 12:45:54]

v8/test/mjsunit and v8/benchmarks did not hit the cases when we omit these
moves. I'd suggest to remove this optimization because it complicates the code
and does not seem to trigger in tests/benchmarks.

+    }
   } else {
     LoadRelocated(temp, Operand(reinterpret_cast<intptr_t>(target), rmode));
   }
@@ -2075,13 +2080,17 @@ int MacroAssembler::CallSize(Label* target) {
 
 
 int MacroAssembler::CallSize(Address target, RelocInfo::Mode rmode) {
-  USE(target);
-
   // Addresses always have 64 bits, so we shouldn't encounter NONE32.
   ASSERT(rmode != RelocInfo::NONE32);
 
   if (rmode == RelocInfo::NONE64) {
-    return kCallSizeWithoutRelocation;
+    int result = kMaxCallSizeWithoutRelocation;
+    if (!predictable_code_size()) {
+      uint64_t imm = reinterpret_cast<uint64_t>(target);
+      if (((imm >> 16) & 0xffff) == 0) result -= kInstructionSize;
+      if (((imm >> 32) & 0xffff) == 0) result -= kInstructionSize;
+    }
+    return result;
   } else {
     return kCallSizeWithRelocation;
   }
@@ -2091,17 +2100,9 @@ int MacroAssembler::CallSize(Address target, RelocInfo::Mode rmode) {
 int MacroAssembler::CallSize(Handle<Code> code,
                              RelocInfo::Mode rmode,
                              TypeFeedbackId ast_id) {
-  USE(code);
   USE(ast_id);
-
-  // Addresses always have 64 bits, so we shouldn't encounter NONE32.
-  ASSERT(rmode != RelocInfo::NONE32);
-
-  if (rmode == RelocInfo::NONE64) {
-    return kCallSizeWithoutRelocation;
-  } else {
-    return kCallSizeWithRelocation;
-  }
+  AllowDeferredHandleDereference embedding_raw_address;
+  return CallSize(reinterpret_cast<Address>(code.location()), rmode);
 }