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[ExecutionEngine] Avoid repeated hash lookups (NFC) #132587

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Merged
merged 1 commit into from
Mar 23, 2025
Merged

[ExecutionEngine] Avoid repeated hash lookups (NFC) #132587

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24 changes: 12 additions & 12 deletions llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1515,15 +1515,15 @@ void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID,
uint64_t Offset = RelI->getOffset();
unsigned RelType = RelI->getType();
// Look for an existing stub.
StubMap::const_iterator i = Stubs.find(Value);
if (i != Stubs.end()) {
auto [It, Inserted] = Stubs.try_emplace(Value);
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@DavidSpickett DavidSpickett Mar 26, 2025

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I think the problem here is that before, we only added an entry to the map if resolveAArch64ShortBranch returned false. Now, it could return true and it's too late, we already added the entry to the map.

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@kazutakahirata kazutakahirata Mar 26, 2025

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@DavidSpickett Ah, I see. Without this patch, we sometimes don't insert a new entry depending on the outcome of resolveAArch64ShortBranch.

Thanks for the revert!

if (!Inserted) {
resolveRelocation(Section, Offset,
Section.getLoadAddressWithOffset(i->second), RelType, 0);
Section.getLoadAddressWithOffset(It->second), RelType, 0);
LLVM_DEBUG(dbgs() << " Stub function found\n");
} else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) {
// Create a new stub function.
LLVM_DEBUG(dbgs() << " Create a new stub function\n");
Stubs[Value] = Section.getStubOffset();
It->second = Section.getStubOffset();
uint8_t *StubTargetAddr = createStubFunction(
Section.getAddressWithOffset(Section.getStubOffset()));

Expand Down Expand Up @@ -1837,15 +1837,15 @@ RuntimeDyldELF::processRelocationRef(
SectionEntry &Section = Sections[SectionID];

// Look up for existing stub.
StubMap::const_iterator i = Stubs.find(Value);
if (i != Stubs.end()) {
RelocationEntry RE(SectionID, Offset, RelType, i->second);
auto [It, Inserted] = Stubs.try_emplace(Value);
if (!Inserted) {
RelocationEntry RE(SectionID, Offset, RelType, It->second);
addRelocationForSection(RE, SectionID);
LLVM_DEBUG(dbgs() << " Stub function found\n");
} else {
// Create a new stub function.
LLVM_DEBUG(dbgs() << " Create a new stub function\n");
Stubs[Value] = Section.getStubOffset();
It->second = Section.getStubOffset();

unsigned AbiVariant = Obj.getPlatformFlags();

Expand Down Expand Up @@ -2075,10 +2075,10 @@ RuntimeDyldELF::processRelocationRef(
SectionEntry &Section = Sections[SectionID];

// Look for an existing stub.
StubMap::const_iterator i = Stubs.find(Value);
auto [It, Inserted] = Stubs.try_emplace(Value);
uintptr_t StubAddress;
if (i != Stubs.end()) {
StubAddress = uintptr_t(Section.getAddressWithOffset(i->second));
if (!Inserted) {
StubAddress = uintptr_t(Section.getAddressWithOffset(It->second));
LLVM_DEBUG(dbgs() << " Stub function found\n");
} else {
// Create a new stub function.
Expand All @@ -2089,7 +2089,7 @@ RuntimeDyldELF::processRelocationRef(
alignTo(BaseAddress + Section.getStubOffset(), getStubAlignment());
unsigned StubOffset = StubAddress - BaseAddress;

Stubs[Value] = StubOffset;
It->second = StubOffset;
createStubFunction((uint8_t *)StubAddress);
RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64,
Value.Offset);
Expand Down
8 changes: 4 additions & 4 deletions llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOARM.h
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Expand Up @@ -307,14 +307,14 @@ class RuntimeDyldMachOARM
// This is an ARM branch relocation, need to use a stub function.
// Look up for existing stub.
SectionEntry &Section = Sections[RE.SectionID];
RuntimeDyldMachO::StubMap::const_iterator i = Stubs.find(Value);
auto [It, Inserted] = Stubs.try_emplace(Value);
uint8_t *Addr;
if (i != Stubs.end()) {
Addr = Section.getAddressWithOffset(i->second);
if (!Inserted) {
Addr = Section.getAddressWithOffset(It->second);
} else {
// Create a new stub function.
assert(Section.getStubOffset() % 4 == 0 && "Misaligned stub");
Stubs[Value] = Section.getStubOffset();
It->second = Section.getStubOffset();
uint32_t StubOpcode = 0;
if (RE.RelType == MachO::ARM_RELOC_BR24)
StubOpcode = 0xe51ff004; // ldr pc, [pc, #-4]
Expand Down
8 changes: 4 additions & 4 deletions llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOX86_64.h
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Expand Up @@ -131,12 +131,12 @@ class RuntimeDyldMachOX86_64
assert(RE.IsPCRel);
assert(RE.Size == 2);
Value.Offset -= RE.Addend;
RuntimeDyldMachO::StubMap::const_iterator i = Stubs.find(Value);
auto [It, Inserted] = Stubs.try_emplace(Value);
uint8_t *Addr;
if (i != Stubs.end()) {
Addr = Section.getAddressWithOffset(i->second);
if (!Inserted) {
Addr = Section.getAddressWithOffset(It->second);
} else {
Stubs[Value] = Section.getStubOffset();
It->second = Section.getStubOffset();
uint8_t *GOTEntry = Section.getAddressWithOffset(Section.getStubOffset());
RelocationEntry GOTRE(RE.SectionID, Section.getStubOffset(),
MachO::X86_64_RELOC_UNSIGNED, Value.Offset, false,
Expand Down