Revision: 4951
Author: [email protected]
Date: Fri Jun 25 04:24:41 2010
Log: Add special case of taking a substring that is the entire string to
stub.
Review URL: http://codereview.chromium.org/2800027
http://code.google.com/p/v8/source/detail?r=4951
Modified:
/branches/bleeding_edge/src/ia32/codegen-ia32.cc
/branches/bleeding_edge/src/x64/codegen-x64.cc
=======================================
--- /branches/bleeding_edge/src/ia32/codegen-ia32.cc Thu Jun 24 06:56:35
2010
+++ /branches/bleeding_edge/src/ia32/codegen-ia32.cc Fri Jun 25 04:24:41
2010
@@ -13295,6 +13295,9 @@
__ test(edx, Immediate(kSmiTagMask));
__ j(not_zero, &runtime);
__ sub(ecx, Operand(edx));
+ __ cmp(ecx, FieldOperand(eax, String::kLengthOffset));
+ Label return_eax;
+ __ j(equal, &return_eax);
// Special handling of sub-strings of length 1 and 2. One character
strings
// are handled in the runtime system (looked up in the single character
// cache). Two character strings are looked for in the symbol cache.
@@ -13399,12 +13402,15 @@
// esi: character of sub string start
StringHelper::GenerateCopyCharactersREP(masm, edi, esi, ecx, ebx, false);
__ mov(esi, edx); // Restore esi.
+
+ __ bind(&return_eax);
__ IncrementCounter(&Counters::sub_string_native, 1);
__ ret(3 * kPointerSize);
// Just jump to runtime to create the sub string.
__ bind(&runtime);
__ TailCallRuntime(Runtime::kSubString, 3, 1);
+
}
=======================================
--- /branches/bleeding_edge/src/x64/codegen-x64.cc Thu Jun 24 07:22:25 2010
+++ /branches/bleeding_edge/src/x64/codegen-x64.cc Fri Jun 25 04:24:41 2010
@@ -11574,7 +11574,9 @@
__ JumpIfNotBothPositiveSmi(rcx, rdx, &runtime);
__ SmiSub(rcx, rcx, rdx, NULL); // Overflow doesn't happen.
- __ j(negative, &runtime);
+ __ cmpq(FieldOperand(rax, String::kLengthOffset), rcx);
+ Label return_rax;
+ __ j(equal, &return_rax);
// Special handling of sub-strings of length 1 and 2. One character
strings
// are handled in the runtime system (looked up in the single character
// cache). Two character strings are looked for in the symbol cache.
@@ -11677,6 +11679,8 @@
// rsi: character of sub string start
StringHelper::GenerateCopyCharactersREP(masm, rdi, rsi, rcx, false);
__ movq(rsi, rdx); // Restore esi.
+
+ __ bind(&return_rax);
__ IncrementCounter(&Counters::sub_string_native, 1);
__ ret(kArgumentsSize);
--
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