Revision: 5457
Author: [email protected]
Date: Wed Sep 15 03:22:55 2010
Log: Replace 2 ARM ldr instructions with one ldrd in the code generated
for a SubStringStub and StringCompareStub in the ARM backend. This
is a commit of http://codereview.chromium.org/3341012 for Andreas
Anyuru.
Review URL: http://codereview.chromium.org/3387003
http://code.google.com/p/v8/source/detail?r=5457
Modified:
/branches/bleeding_edge/AUTHORS
/branches/bleeding_edge/src/arm/code-stubs-arm.cc
=======================================
--- /branches/bleeding_edge/AUTHORS Fri Sep 10 01:12:34 2010
+++ /branches/bleeding_edge/AUTHORS Wed Sep 15 03:22:55 2010
@@ -9,6 +9,7 @@
Alexander Botero-Lowry <[email protected]>
Alexandre Vassalotti <[email protected]>
+Andreas Anyuru <[email protected]>
Burcu Dogan <[email protected]>
Craig Schlenter <[email protected]>
Daniel Andersson <[email protected]>
=======================================
--- /branches/bleeding_edge/src/arm/code-stubs-arm.cc Wed Sep 15 03:14:25
2010
+++ /branches/bleeding_edge/src/arm/code-stubs-arm.cc Wed Sep 15 03:22:55
2010
@@ -4187,17 +4187,21 @@
// Check bounds and smi-ness.
- __ ldr(r7, MemOperand(sp, kToOffset));
- __ ldr(r6, MemOperand(sp, kFromOffset));
+ Register to = r6;
+ Register from = r7;
+ __ Ldrd(to, from, MemOperand(sp, kToOffset));
+ STATIC_ASSERT(kFromOffset == kToOffset + 4);
STATIC_ASSERT(kSmiTag == 0);
STATIC_ASSERT(kSmiTagSize + kSmiShiftSize == 1);
// I.e., arithmetic shift right by one un-smi-tags.
- __ mov(r2, Operand(r7, ASR, 1), SetCC);
- __ mov(r3, Operand(r6, ASR, 1), SetCC, cc);
- // If either r2 or r6 had the smi tag bit set, then carry is set now.
+ __ mov(r2, Operand(to, ASR, 1), SetCC);
+ __ mov(r3, Operand(from, ASR, 1), SetCC, cc);
+ // If either to or from had the smi tag bit set, then carry is set now.
__ b(cs, &runtime); // Either "from" or "to" is not a smi.
__ b(mi, &runtime); // From is negative.
+ // Both to and from are smis.
+
__ sub(r2, r2, Operand(r3), SetCC);
__ b(mi, &runtime); // Fail if from > to.
// Special handling of sub-strings of length 1 and 2. One character
strings
@@ -4208,8 +4212,8 @@
// r2: length
// r3: from index (untaged smi)
- // r6: from (smi)
- // r7: to (smi)
+ // r6 (a.k.a. to): to (smi)
+ // r7 (a.k.a. from): from offset (smi)
// Make sure first argument is a sequential (or flat) string.
__ ldr(r5, MemOperand(sp, kStringOffset));
@@ -4221,10 +4225,10 @@
// r1: instance type
// r2: length
- // r3: from index (untaged smi)
+ // r3: from index (untagged smi)
// r5: string
- // r6: from (smi)
- // r7: to (smi)
+ // r6 (a.k.a. to): to (smi)
+ // r7 (a.k.a. from): from offset (smi)
Label seq_string;
__ and_(r4, r1, Operand(kStringRepresentationMask));
STATIC_ASSERT(kSeqStringTag < kConsStringTag);
@@ -4250,17 +4254,18 @@
// r2: length
// r3: from index (untaged smi)
// r5: string
- // r6: from (smi)
- // r7: to (smi)
+ // r6 (a.k.a. to): to (smi)
+ // r7 (a.k.a. from): from offset (smi)
__ ldr(r4, FieldMemOperand(r5, String::kLengthOffset));
- __ cmp(r4, Operand(r7));
+ __ cmp(r4, Operand(to));
__ b(lt, &runtime); // Fail if to > length.
+ to = no_reg;
// r1: instance type.
// r2: result string length.
// r3: from index (untaged smi)
// r5: string.
- // r6: from offset (smi)
+ // r7 (a.k.a. from): from offset (smi)
// Check for flat ascii string.
Label non_ascii_flat;
__ tst(r1, Operand(kStringEncodingMask));
@@ -4302,12 +4307,12 @@
// r0: result string.
// r2: result string length.
// r5: string.
- // r6: from offset (smi)
+ // r7 (a.k.a. from): from offset (smi)
// Locate first character of result.
__ add(r1, r0, Operand(SeqAsciiString::kHeaderSize - kHeapObjectTag));
// Locate 'from' character of string.
__ add(r5, r5, Operand(SeqAsciiString::kHeaderSize - kHeapObjectTag));
- __ add(r5, r5, Operand(r6, ASR, 1));
+ __ add(r5, r5, Operand(from, ASR, 1));
// r0: result string.
// r1: first character of result string.
@@ -4323,7 +4328,7 @@
__ bind(&non_ascii_flat);
// r2: result string length.
// r5: string.
- // r6: from offset (smi)
+ // r7 (a.k.a. from): from offset (smi)
// Check for flat two byte string.
// Allocate the result.
@@ -4335,18 +4340,19 @@
// Locate first character of result.
__ add(r1, r0, Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
// Locate 'from' character of string.
- __ add(r5, r5, Operand(SeqTwoByteString::kHeaderSize -
kHeapObjectTag));
+ __ add(r5, r5, Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
// As "from" is a smi it is 2 times the value which matches the size of
a two
// byte character.
- __ add(r5, r5, Operand(r6));
+ __ add(r5, r5, Operand(from));
+ from = no_reg;
// r0: result string.
// r1: first character of result.
// r2: result length.
// r5: first character of string to copy.
STATIC_ASSERT((SeqTwoByteString::kHeaderSize & kObjectAlignmentMask) ==
0);
- StringHelper::GenerateCopyCharactersLong(masm, r1, r5, r2, r3, r4, r6,
r7, r9,
- DEST_ALWAYS_ALIGNED);
+ StringHelper::GenerateCopyCharactersLong(
+ masm, r1, r5, r2, r3, r4, r6, r7, r9, DEST_ALWAYS_ALIGNED);
__ IncrementCounter(&Counters::sub_string_native, 1, r3, r4);
__ add(sp, sp, Operand(3 * kPointerSize));
__ Ret();
@@ -4422,8 +4428,7 @@
// Stack frame on entry.
// sp[0]: right string
// sp[4]: left string
- __ ldr(r0, MemOperand(sp, 1 * kPointerSize)); // left
- __ ldr(r1, MemOperand(sp, 0 * kPointerSize)); // right
+ __ Ldrd(r0 , r1, MemOperand(sp)); // Load right in r0, left in r1.
Label not_same;
__ cmp(r0, r1);
@@ -4438,12 +4443,12 @@
__ bind(¬_same);
// Check that both objects are sequential ascii strings.
- __ JumpIfNotBothSequentialAsciiStrings(r0, r1, r2, r3, &runtime);
+ __ JumpIfNotBothSequentialAsciiStrings(r1, r0, r2, r3, &runtime);
// Compare flat ascii strings natively. Remove arguments from stack
first.
__ IncrementCounter(&Counters::string_compare_native, 1, r2, r3);
__ add(sp, sp, Operand(2 * kPointerSize));
- GenerateCompareFlatAsciiStrings(masm, r0, r1, r2, r3, r4, r5);
+ GenerateCompareFlatAsciiStrings(masm, r1, r0, r2, r3, r4, r5);
// Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
// tagged as a small integer.
--
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