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

src/arm/stub-cache-arm.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 23 matching lines @@
 #include "stub-cache.h"
 
 namespace v8 {
 namespace internal {
 
 #define __ ACCESS_MASM(masm)
 
 
 static void ProbeTable(Isolate* isolate,
                        MacroAssembler* masm,
-                       Code::Flags flags,
+                       Register flags,
                        StubCache::Table table,
                        Register name,
                        Register offset,
                        Register scratch,
                        Register scratch2) {
   ExternalReference key_offset(isolate->stub_cache()->key_reference(table));
   ExternalReference value_offset(isolate->stub_cache()->value_reference(table));
 
   uint32_t key_off_addr = reinterpret_cast<uint32_t>(key_offset.address());
   uint32_t value_off_addr = reinterpret_cast<uint32_t>(value_offset.address());
 
   // Check the relative positions of the address fields.
   ASSERT(value_off_addr > key_off_addr);
   ASSERT((value_off_addr - key_off_addr) % 4 == 0);
   ASSERT((value_off_addr - key_off_addr) < (256 * 4));
 
   Label miss;
   Register offsets_base_addr = scratch;
 
   // 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));
   __ bic(scratch2, scratch2, Operand(Code::kFlagsNotUsedInLookup));
   __ cmp(scratch2, Operand(flags));
   __ 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));
   __ Jump(offset);
 
   // Miss: fall through.
   __ bind(&miss);
 }
 
 
@@ skipping 61 matching lines @@
   return result;
 }
 
 
 void StubCache::GenerateProbe(MacroAssembler* masm,
                               Code::Flags flags,
                               Register receiver,
                               Register name,
                               Register scratch,
                               Register extra,
-                              Register extra2) {
+                              Register extra2,
+                              Register extra3) {
   Isolate* isolate = masm->isolate();
   Label miss;
 
   // Make sure that code is valid. The shifting code relies on the
   // entry size being 8.
   ASSERT(sizeof(Entry) == 8);
 
   // 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));
-
-  // Check scratch, extra and extra2 registers are valid.
-  ASSERT(!scratch.is(no_reg));
-  ASSERT(!extra.is(no_reg));
-  ASSERT(!extra2.is(no_reg));
+  // 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 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.
   __ bind(&miss);
 }
 
 
 void StubCompiler::GenerateLoadGlobalFunctionPrototype(MacroAssembler* masm,
                                                        int index,
                                                        Register prototype) {
@@ skipping 3953 matching lines @@
       masm->isolate()->builtins()->KeyedStoreIC_MissForceGeneric();
   __ Jump(ic, RelocInfo::CODE_TARGET);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM