Revision: 11506
Author: [email protected]
Date: Fri May 4 01:34:59 2012
Log: MIPS: Fix register clobbering in LoadIC for interceptors.
Port r11492 (d14ada19)
Original commit message:
Fix register clobbering in LoadIC for interceptors.
This fixes a corner-case where the receiver register was clobbered by
LoadICs for interceptors and inlined followup code still relied on the
receiver to be intact in case of prototype changes.
BUG=
TEST=
Review URL: https://chromiumcodereview.appspot.com/10315016
Patch from Akos Palfi <[email protected]>.
http://code.google.com/p/v8/source/detail?r=11506
Modified:
/branches/bleeding_edge/src/mips/stub-cache-mips.cc
=======================================
--- /branches/bleeding_edge/src/mips/stub-cache-mips.cc Fri Apr 27 05:57:01
2012
+++ /branches/bleeding_edge/src/mips/stub-cache-mips.cc Fri May 4 01:34:59
2012
@@ -1287,12 +1287,19 @@
name, miss);
ASSERT(holder_reg.is(receiver) || holder_reg.is(scratch1));
+ // Preserve the receiver register explicitly whenever it is different
from
+ // the holder and it is needed should the interceptor return without
any
+ // result. The CALLBACKS case needs the receiver to be passed into C++
code,
+ // the FIELD case might cause a miss during the prototype check.
+ bool must_perfrom_prototype_check = *interceptor_holder !=
lookup->holder();
+ bool must_preserve_receiver_reg = !receiver.is(holder_reg) &&
+ (lookup->type() == CALLBACKS || must_perfrom_prototype_check);
+
// Save necessary data before invoking an interceptor.
// Requires a frame to make GC aware of pushed pointers.
{
FrameScope frame_scope(masm(), StackFrame::INTERNAL);
- if (lookup->type() == CALLBACKS && !receiver.is(holder_reg)) {
- // CALLBACKS case needs a receiver to be passed into C++ callback.
+ if (must_preserve_receiver_reg) {
__ Push(receiver, holder_reg, name_reg);
} else {
__ Push(holder_reg, name_reg);
@@ -1316,14 +1323,14 @@
__ bind(&interceptor_failed);
__ pop(name_reg);
__ pop(holder_reg);
- if (lookup->type() == CALLBACKS && !receiver.is(holder_reg)) {
+ if (must_preserve_receiver_reg) {
__ pop(receiver);
}
// Leave the internal frame.
}
// Check that the maps from interceptor's holder to lookup's holder
// haven't changed. And load lookup's holder into |holder| register.
- if (*interceptor_holder != lookup->holder()) {
+ if (must_perfrom_prototype_check) {
holder_reg = CheckPrototypes(interceptor_holder,
holder_reg,
Handle<JSObject>(lookup->holder()),
--
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