Title: [295606] trunk/Source/_javascript_Core/b3/air/AirAllocateRegistersAndStackAndGenerateCode.cpp
- Revision
- 295606
- Author
- sbar...@apple.com
- Date
- 2022-06-16 12:51:36 -0700 (Thu, 16 Jun 2022)
Log Message
Change how we rewind instructions in Air's O0 register allocator
https://bugs.webkit.org/show_bug.cgi?id=241687
Reviewed by Mark Lam.
* Source/_javascript_Core/b3/air/AirAllocateRegistersAndStackAndGenerateCode.cpp:
(JSC::B3::Air::GenerateAndAllocateRegisters::generate):
Canonical link: https://commits.webkit.org/251611@main
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/b3/air/AirAllocateRegistersAndStackAndGenerateCode.cpp (295605 => 295606)
--- trunk/Source/_javascript_Core/b3/air/AirAllocateRegistersAndStackAndGenerateCode.cpp 2022-06-16 19:44:58 UTC (rev 295605)
+++ trunk/Source/_javascript_Core/b3/air/AirAllocateRegistersAndStackAndGenerateCode.cpp 2022-06-16 19:51:36 UTC (rev 295606)
@@ -590,6 +590,7 @@
context.indexInBlock = instIndex;
Inst& inst = block->at(instIndex);
+ Inst instCopy = inst;
m_namedUsedRegs = RegisterSet();
m_namedDefdRegs = RegisterSet();
@@ -753,26 +754,7 @@
if (!success) {
RELEASE_ASSERT(!isReplayingSameInst); // We should only need to do the below at most once per inst.
- // We need to capture the register state before we start spilling things
- // since we may have multiple arguments that are the same register.
- IndexMap<Reg, Tmp> allocationSnapshot = currentAllocation;
-
- // We rewind this Inst to be in its previous state, however, if any arg admits stack,
- // we move to providing that arg in stack form. This will allow us to fully allocate
- // this inst when we rewind.
- inst.forEachTmpFast([&] (Tmp& tmp) {
- if (!tmp.isReg())
- return;
- if (isDisallowedRegister(tmp.reg()))
- return;
- Tmp originalTmp = allocationSnapshot[tmp.reg()];
- if (originalTmp.isReg()) {
- ASSERT(tmp.reg() == originalTmp.reg());
- // This means this Inst referred to this reg directly. We leave these as is.
- return;
- }
- tmp = originalTmp;
- });
+ inst = instCopy;
inst.forEachArg([&] (Arg& arg, Arg::Role, Bank, Width) {
if (arg.isTmp() && !arg.tmp().isReg() && inst.admitsStack(arg)) {
Tmp tmp = arg.tmp();
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