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Bug 1958280 part 3 - Tidy up the code for adding GC allocations to safepoints. r=iain

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Differential Revision: https://phabricator.services.mozilla.com/D246440
This commit is contained in:
Jan de Mooij
2025-04-29 11:27:34 +00:00
parent b4f222009b
commit 8e0af933ff
3 changed files with 88 additions and 86 deletions
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89
js/src/jit/BacktrackingAllocator.cpp
View File

@@ -4612,43 +4612,6 @@ size_t BacktrackingAllocator::findFirstSafepoint(CodePosition pos,
return i;
}
// Helper for ::populateSafepoints
static inline bool IsNunbox(VirtualRegister& reg) {
#ifdef JS_NUNBOX32
return reg.type() == LDefinition::TYPE || reg.type() == LDefinition::PAYLOAD;
#else
return false;
#endif
}
// Helper for ::populateSafepoints
static inline bool IsSlotsOrElements(VirtualRegister& reg) {
return reg.type() == LDefinition::SLOTS;
}
// Helper for ::populateSafepoints
static inline bool IsTraceable(VirtualRegister& reg) {
if (reg.type() == LDefinition::OBJECT ||
reg.type() == LDefinition::WASM_ANYREF) {
return true;
}
#ifdef JS_PUNBOX64
if (reg.type() == LDefinition::BOX) {
return true;
}
#endif
if (reg.type() == LDefinition::STACKRESULTS) {
MOZ_ASSERT(reg.def());
const LStackArea* alloc = reg.def()->output()->toStackArea();
for (auto iter = alloc->results(); iter; iter.next()) {
if (iter.isWasmAnyRef()) {
return true;
}
}
}
return false;
}
bool BacktrackingAllocator::populateSafepoints() {
JitSpew(JitSpew_RegAlloc, "Populating Safepoints");
@@ -4661,8 +4624,7 @@ bool BacktrackingAllocator::populateSafepoints() {
for (uint32_t i = 1; i < graph.numVirtualRegisters(); i++) {
VirtualRegister& reg = vregs[i];
if (!reg.def() ||
(!IsTraceable(reg) && !IsSlotsOrElements(reg) && !IsNunbox(reg))) {
if (!reg.def() || !reg.def()->isSafepointGCType(reg.ins())) {
continue;
}
@@ -4711,53 +4673,8 @@ bool BacktrackingAllocator::populateSafepoints() {
continue;
}
switch (reg.type()) {
case LDefinition::OBJECT:
if (!safepoint->addGcPointer(a)) {
return false;
}
break;
case LDefinition::SLOTS:
if (!safepoint->addSlotsOrElementsPointer(a)) {
return false;
}
break;
case LDefinition::WASM_ANYREF:
if (!safepoint->addWasmAnyRef(a)) {
return false;
}
break;
case LDefinition::STACKRESULTS: {
MOZ_ASSERT(a.isStackArea());
for (auto iter = a.toStackArea()->results(); iter; iter.next()) {
if (iter.isWasmAnyRef()) {
if (!safepoint->addWasmAnyRef(iter.alloc())) {
return false;
}
}
}
break;
}
#ifdef JS_NUNBOX32
case LDefinition::TYPE:
if (!safepoint->addNunboxType(i, a)) {
return false;
}
break;
case LDefinition::PAYLOAD:
if (!safepoint->addNunboxPayload(i, a)) {
return false;
}
break;
#else
case LDefinition::BOX:
if (!safepoint->addBoxedValue(a)) {
return false;
}
break;
#endif
default:
MOZ_CRASH("Bad register type");
if (!safepoint->addGCAllocation(i, reg.def(), a)) {
return false;
}
}
}

45
js/src/jit/LIR.cpp
View File

@@ -681,6 +681,51 @@ void LInstruction::initSafepoint(TempAllocator& alloc) {
MOZ_ASSERT(safepoint_);
}
bool LSafepoint::addGCAllocation(uint32_t vregId, LDefinition* def,
LAllocation a) {
switch (def->type()) {
case LDefinition::OBJECT:
return addGcPointer(a);
case LDefinition::SLOTS:
return addSlotsOrElementsPointer(a);
case LDefinition::WASM_ANYREF:
return addWasmAnyRef(a);
#ifdef JS_NUNBOX32
case LDefinition::TYPE:
return addNunboxType(vregId, a);
case LDefinition::PAYLOAD:
return addNunboxPayload(vregId, a);
#else
case LDefinition::BOX:
return addBoxedValue(a);
#endif
case LDefinition::STACKRESULTS: {
MOZ_ASSERT(a.isStackArea());
for (auto iter = a.toStackArea()->results(); iter; iter.next()) {
if (iter.isWasmAnyRef()) {
if (!addWasmAnyRef(iter.alloc())) {
return false;
}
}
}
return true;
}
case LDefinition::GENERAL:
case LDefinition::INT32:
case LDefinition::FLOAT32:
case LDefinition::DOUBLE:
case LDefinition::SIMD128:
break;
}
MOZ_CRASH("Bad register type");
}
bool LMoveGroup::add(LAllocation from, LAllocation to, LDefinition::Type type) {
#ifdef DEBUG
MOZ_ASSERT(from != to);

40
js/src/jit/LIR.h
View File

@@ -36,6 +36,7 @@ class LStackArea;
class LArgument;
class LConstantIndex;
class LInstruction;
class LNode;
class LDefinition;
class MBasicBlock;
class MIRGenerator;
@@ -660,6 +661,11 @@ class LDefinition {
return output_.toConstantIndex()->index();
}
// Returns true if this definition should be added to safepoints for GC
// tracing. This includes Value type tags on 32-bit and slots/elements
// pointers.
inline bool isSafepointGCType(LNode* ins) const;
static inline Type TypeFrom(MIRType type) {
switch (type) {
case MIRType::Boolean:
@@ -1899,6 +1905,9 @@ class LSafepoint : public TempObject {
#endif // JS_PUNBOX64
[[nodiscard]] bool addGCAllocation(uint32_t vregId, LDefinition* def,
LAllocation a);
bool encoded() const { return safepointOffset_ != INVALID_SAFEPOINT_OFFSET; }
uint32_t offset() const {
MOZ_ASSERT(encoded());
@@ -1997,6 +2006,37 @@ class LInstruction::InputIterator {
LAllocation* operator->() const { return **this; }
};
bool LDefinition::isSafepointGCType(LNode* ins) const {
switch (type()) {
case LDefinition::OBJECT:
case LDefinition::SLOTS:
case LDefinition::WASM_ANYREF:
#ifdef JS_NUNBOX32
case LDefinition::TYPE:
case LDefinition::PAYLOAD:
#else
case LDefinition::BOX:
#endif
return true;
case LDefinition::STACKRESULTS: {
LStackArea alloc(ins->toInstruction());
for (auto iter = alloc.results(); iter; iter.next()) {
if (iter.isWasmAnyRef()) {
return true;
}
}
return false;
}
case LDefinition::GENERAL:
case LDefinition::INT32:
case LDefinition::FLOAT32:
case LDefinition::DOUBLE:
case LDefinition::SIMD128:
return false;
}
MOZ_CRASH("invalid type");
}
class LIRGraph {
struct ValueHasher {
using Lookup = Value;