ARM: Reduce amount of code generated for LoadIC_Megamorphic....

src/arm/stub-cache-arm.cc

Index: src/arm/stub-cache-arm.cc
===================================================================
--- src/arm/stub-cache-arm.cc	(revision 8507)
+++ src/arm/stub-cache-arm.cc	(working copy)
@@ -41,7 +41,7 @@
 
 static void ProbeTable(Isolate* isolate,
                        MacroAssembler* masm,
-                       Code::Flags flags,
+                       Register flags,
                        StubCache::Table table,
                        Register name,
                        Register offset,
@@ -63,14 +63,13 @@
 
   // Check that the key in the entry matches the name.
   __ mov(offsets_base_addr, Operand(key_offset));
-  __ ldr(ip, MemOperand(offsets_base_addr, offset, LSL, 1));
+  __ ldr(ip, MemOperand(offsets_base_addr, offset, LSL, 1, PreIndex));
   __ cmp(name, ip);
   __ b(ne, &miss);
 
   // Get the code entry from the cache.
-  __ add(offsets_base_addr, offsets_base_addr,
-         Operand(value_off_addr - key_off_addr));
-  __ ldr(scratch2, MemOperand(offsets_base_addr, offset, LSL, 1));
+  __ ldr(scratch2, MemOperand(offsets_base_addr,
+          value_off_addr - key_off_addr));

[Erik Corry, 2011/07/04 06:54:34]

Strange indentation here.  The value_off_addr should line up with the
offsets_base_addr.  Alternatively the MemOperand should line up with the
scratch2.

[m.m.capewell, 2011/07/14 15:00:18]

Done.

 
   // Check that the flags match what we're looking for.
   __ ldr(scratch2, FieldMemOperand(scratch2, Code::kFlagsOffset));
@@ -79,7 +78,7 @@
   __ b(ne, &miss);
 
   // Re-load code entry from cache.
-  __ ldr(offset, MemOperand(offsets_base_addr, offset, LSL, 1));
+  __ ldr(offset, MemOperand(offsets_base_addr, value_off_addr - key_off_addr));
 
   // Jump to the first instruction in the code stub.
   __ add(offset, offset, Operand(Code::kHeaderSize - kHeapObjectTag));
@@ -161,7 +160,8 @@
                               Register name,
                               Register scratch,
                               Register extra,
-                              Register extra2) {
+                              Register extra2,
+                              Register extra3) {
   Isolate* isolate = masm->isolate();
   Label miss;
 
@@ -172,46 +172,37 @@
   // Make sure the flags does not name a specific type.
   ASSERT(Code::ExtractTypeFromFlags(flags) == 0);
 
-  // Make sure that there are no register conflicts.
-  ASSERT(!scratch.is(receiver));
-  ASSERT(!scratch.is(name));
-  ASSERT(!extra.is(receiver));
-  ASSERT(!extra.is(name));
-  ASSERT(!extra.is(scratch));
-  ASSERT(!extra2.is(receiver));
-  ASSERT(!extra2.is(name));
-  ASSERT(!extra2.is(scratch));
-  ASSERT(!extra2.is(extra));
+  // Make sure that there are no register conflicts and registers are valid.
+  ASSERT(Assembler::NumRegistersInRegList(receiver.bit() | name.bit() |
+    scratch.bit() | extra.bit() | extra2.bit() | extra3.bit()) == 6);
 
-  // Check scratch, extra and extra2 registers are valid.
-  ASSERT(!scratch.is(no_reg));
-  ASSERT(!extra.is(no_reg));
-  ASSERT(!extra2.is(no_reg));
-
   // Check that the receiver isn't a smi.
   __ JumpIfSmi(receiver, &miss);
 
+  // Copy flags into a register.
+  __ mov(extra3, Operand(flags));
+
   // Get the map of the receiver and compute the hash.
   __ ldr(scratch, FieldMemOperand(name, String::kHashFieldOffset));
   __ ldr(ip, FieldMemOperand(receiver, HeapObject::kMapOffset));
   __ add(scratch, scratch, Operand(ip));
-  __ eor(scratch, scratch, Operand(flags));
+  __ eor(scratch, scratch, Operand(extra3));
   __ and_(scratch,
           scratch,
           Operand((kPrimaryTableSize - 1) << kHeapObjectTagSize));
 
   // Probe the primary table.
-  ProbeTable(isolate, masm, flags, kPrimary, name, scratch, extra, extra2);
+  ProbeTable(isolate, masm, extra3, kPrimary, name, scratch, extra, extra2);
 
   // Primary miss: Compute hash for secondary probe.
   __ sub(scratch, scratch, Operand(name));
-  __ add(scratch, scratch, Operand(flags));
+  __ add(scratch, scratch, Operand(extra3));
   __ and_(scratch,
           scratch,
           Operand((kSecondaryTableSize - 1) << kHeapObjectTagSize));
 
   // Probe the secondary table.
-  ProbeTable(isolate, masm, flags, kSecondary, name, scratch, extra, extra2);
+  ProbeTable(isolate, masm, extra3, kSecondary, name, scratch, extra, extra2);
 
   // Cache miss: Fall-through and let caller handle the miss by
   // entering the runtime system.