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[TailDuplicator] Determine if computed gotos using blockaddress #132536

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Merged
merged 6 commits into from
Mar 26, 2025
Merged

[TailDuplicator] Determine if computed gotos using blockaddress #132536

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33b40ec
Add test cases
dianqk Mar 22, 2025
4ed0b5f
[TailDuplicator] Determine if computed gotos using blockaddress
dianqk Mar 22, 2025
6275a07
Address feedback
dianqk Mar 24, 2025
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dianqk Mar 25, 2025
246f4a0
Compact the register numbers by register-coalescer
dianqk Mar 26, 2025
c4204e2
Document terminatorIsComputedGoto
dianqk Mar 26, 2025
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7 changes: 4 additions & 3 deletions llvm/include/llvm/CodeGen/MachineInstr.h
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Original file line number Diff line number Diff line change
Expand Up @@ -997,9 +997,7 @@ class MachineInstr
bool isIndirectBranch(QueryType Type = AnyInBundle,
bool IncludeJumpTable = true) const {
return hasProperty(MCID::IndirectBranch, Type) &&
(IncludeJumpTable || !llvm::any_of(operands(), [](const auto &Op) {
return Op.isJTI();
}));
(IncludeJumpTable || jumpToIRBlockAddressTaken());
}

bool isComputedGoto(QueryType Type = AnyInBundle) const {
Expand Down Expand Up @@ -2088,6 +2086,9 @@ class MachineInstr
MCSymbol *PreInstrSymbol, MCSymbol *PostInstrSymbol,
MDNode *HeapAllocMarker, MDNode *PCSections,
uint32_t CFIType, MDNode *MMRAs);

/// Returns true if all successors are IRBlockAddressTaken.
bool jumpToIRBlockAddressTaken() const;
};

/// Special DenseMapInfo traits to compare MachineInstr* by *value* of the
Expand Down
6 changes: 6 additions & 0 deletions llvm/lib/CodeGen/MachineInstr.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -359,6 +359,12 @@ void MachineInstr::setExtraInfo(MachineFunction &MF,
Info.set<EIIK_MMO>(MMOs[0]);
}

bool MachineInstr::jumpToIRBlockAddressTaken() const {
return llvm::all_of(getParent()->successors(), [](const auto *Succ) {
return Succ->isIRBlockAddressTaken();
});
}

void MachineInstr::dropMemRefs(MachineFunction &MF) {
if (memoperands_empty())
return;
Expand Down
174 changes: 164 additions & 10 deletions llvm/test/CodeGen/X86/tail-dup-computed-goto.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -8,9 +8,21 @@
declare i64 @f3()
declare i64 @f4()
declare i64 @f5()
@computed_goto.dispatch = external global [5 x ptr]
define void @computed_goto() { ret void }
@computed_goto.dispatch = constant [5 x ptr] [ptr null, ptr blockaddress(@computed_goto, %bb1), ptr blockaddress(@computed_goto, %bb2), ptr blockaddress(@computed_goto, %bb3), ptr blockaddress(@computed_goto, %bb4)]
define void @computed_goto() {
start:
ret void
bb1:
ret void
bb2:
ret void
bb3:
ret void
bb4:
ret void
}
define void @jump_table() { ret void }
define void @jump_table_pic() { ret void }
...
---
name: computed_goto
Expand All @@ -28,7 +40,7 @@ body: |
; CHECK-NEXT: [[COPY2:%[0-9]+]]:gr64_nosp = COPY [[COPY1]]
; CHECK-NEXT: JMP64m $noreg, 8, [[COPY1]], @computed_goto.dispatch, $noreg
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.1:
; CHECK-NEXT: bb.1.bb1 (ir-block-address-taken %ir-block.bb1):
; CHECK-NEXT: successors: %bb.1(0x20000000), %bb.2(0x20000000), %bb.3(0x20000000), %bb.4(0x20000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
Expand All @@ -39,7 +51,7 @@ body: |
; CHECK-NEXT: [[COPY5:%[0-9]+]]:gr64_nosp = COPY [[COPY4]]
; CHECK-NEXT: JMP64m $noreg, 8, [[COPY4]], @computed_goto.dispatch, $noreg
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.2:
; CHECK-NEXT: bb.2.bb2 (ir-block-address-taken %ir-block.bb2):
; CHECK-NEXT: successors: %bb.1(0x20000000), %bb.2(0x20000000), %bb.3(0x20000000), %bb.4(0x20000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
Expand All @@ -50,7 +62,7 @@ body: |
; CHECK-NEXT: [[COPY8:%[0-9]+]]:gr64_nosp = COPY [[COPY7]]
; CHECK-NEXT: JMP64m $noreg, 8, [[COPY7]], @computed_goto.dispatch, $noreg
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.3:
; CHECK-NEXT: bb.3.bb3 (ir-block-address-taken %ir-block.bb3):
; CHECK-NEXT: successors: %bb.1(0x20000000), %bb.2(0x20000000), %bb.3(0x20000000), %bb.4(0x20000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
Expand All @@ -61,7 +73,7 @@ body: |
; CHECK-NEXT: [[COPY11:%[0-9]+]]:gr64_nosp = COPY [[COPY10]]
; CHECK-NEXT: JMP64m $noreg, 8, [[COPY10]], @computed_goto.dispatch, $noreg
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.4:
; CHECK-NEXT: bb.4.bb4 (ir-block-address-taken %ir-block.bb4):
; CHECK-NEXT: successors: %bb.1(0x20000000), %bb.2(0x20000000), %bb.3(0x20000000), %bb.4(0x20000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
Expand All @@ -79,31 +91,31 @@ body: |
%0:gr64 = COPY %6
JMP_1 %bb.5

bb.1:
bb.1.bb1 (ir-block-address-taken %ir-block.bb1):
ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
CALL64pcrel32 target-flags(x86-plt) @f1, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
%10:gr64 = COPY $rax
%1:gr64 = COPY %10
JMP_1 %bb.5

bb.2:
bb.2.bb2 (ir-block-address-taken %ir-block.bb2):
ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
CALL64pcrel32 target-flags(x86-plt) @f2, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
%9:gr64 = COPY $rax
%2:gr64 = COPY %9
JMP_1 %bb.5

bb.3:
bb.3.bb3 (ir-block-address-taken %ir-block.bb3):
ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
CALL64pcrel32 target-flags(x86-plt) @f3, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
%8:gr64 = COPY $rax
%3:gr64 = COPY %8
JMP_1 %bb.5

bb.4:
bb.4.bb4 (ir-block-address-taken %ir-block.bb4):
ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
CALL64pcrel32 target-flags(x86-plt) @f4, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
Expand Down Expand Up @@ -253,3 +265,145 @@ body: |
bb.7:

...
---
name: jump_table_pic
tracksRegLiveness: true
jumpTable:
kind: block-address
entries:
- id: 0
blocks: [ '%bb.2', '%bb.3', '%bb.4', '%bb.5', '%bb.6' ]
body: |
; CHECK-LABEL: name: jump_table_pic
; CHECK: bb.0:
; CHECK-NEXT: successors: %bb.1(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: CALL64pcrel32 target-flags(x86-plt) @f0, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
; CHECK-NEXT: ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: [[COPY:%[0-9]+]]:gr64 = COPY $rax
; CHECK-NEXT: [[COPY1:%[0-9]+]]:gr64 = COPY [[COPY]]
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.1:
; CHECK-NEXT: successors: %bb.3(0x1999999a), %bb.4(0x1999999a), %bb.5(0x1999999a), %bb.6(0x1999999a), %bb.7(0x1999999a)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: [[PHI:%[0-9]+]]:gr64 = PHI [[COPY1]], %bb.0, %3, %bb.7, %4, %bb.6, %5, %bb.5, %6, %bb.4, %7, %bb.3
; CHECK-NEXT: [[DEC64r:%[0-9]+]]:gr64_nosp = DEC64r [[PHI]], implicit-def dead $eflags
; CHECK-NEXT: [[LEA64r:%[0-9]+]]:gr64 = LEA64r $rip, 1, $noreg, %jump-table.0, $noreg
; CHECK-NEXT: [[MOVSX64rm32_:%[0-9]+]]:gr64 = MOVSX64rm32 [[DEC64r]], 4, [[DEC64r]], 0, $noreg :: (load (s32) from jump-table)
; CHECK-NEXT: [[ADD64rr:%[0-9]+]]:gr64 = ADD64rr [[LEA64r]], [[MOVSX64rm32_]], implicit-def dead $eflags
; CHECK-NEXT: JMP64r [[ADD64rr]]
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.3:
; CHECK-NEXT: successors: %bb.1(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: CALL64pcrel32 target-flags(x86-plt) @f1, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
; CHECK-NEXT: ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: [[COPY2:%[0-9]+]]:gr64 = COPY $rax
; CHECK-NEXT: [[COPY3:%[0-9]+]]:gr64 = COPY [[COPY2]]
; CHECK-NEXT: JMP_1 %bb.1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.4:
; CHECK-NEXT: successors: %bb.1(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: CALL64pcrel32 target-flags(x86-plt) @f2, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
; CHECK-NEXT: ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: [[COPY4:%[0-9]+]]:gr64 = COPY $rax
; CHECK-NEXT: [[COPY5:%[0-9]+]]:gr64 = COPY [[COPY4]]
; CHECK-NEXT: JMP_1 %bb.1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.5:
; CHECK-NEXT: successors: %bb.1(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: CALL64pcrel32 target-flags(x86-plt) @f3, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
; CHECK-NEXT: ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: [[COPY6:%[0-9]+]]:gr64 = COPY $rax
; CHECK-NEXT: [[COPY7:%[0-9]+]]:gr64 = COPY [[COPY6]]
; CHECK-NEXT: JMP_1 %bb.1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.6:
; CHECK-NEXT: successors: %bb.1(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: CALL64pcrel32 target-flags(x86-plt) @f4, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
; CHECK-NEXT: ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: [[COPY8:%[0-9]+]]:gr64 = COPY $rax
; CHECK-NEXT: [[COPY9:%[0-9]+]]:gr64 = COPY [[COPY8]]
; CHECK-NEXT: JMP_1 %bb.1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.7:
; CHECK-NEXT: successors: %bb.1(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: CALL64pcrel32 target-flags(x86-plt) @f5, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
; CHECK-NEXT: ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
; CHECK-NEXT: [[COPY10:%[0-9]+]]:gr64 = COPY $rax
; CHECK-NEXT: [[COPY11:%[0-9]+]]:gr64 = COPY [[COPY10]]
; CHECK-NEXT: JMP_1 %bb.1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.8:
bb.0:
ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
CALL64pcrel32 target-flags(x86-plt) @f0, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
%7:gr64 = COPY $rax
%0:gr64 = COPY %7
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Could compact the register numbers, these will be renumbered on MIR parse which can be confusing when later debugging the testacy


bb.1:
%1:gr64 = PHI %0, %bb.0, %6, %bb.6, %5, %bb.5, %4, %bb.4, %3, %bb.3, %2, %bb.2
%8:gr64_nosp = DEC64r %1, implicit-def dead $eflags

bb.8:
successors: %bb.2(0x1999999a), %bb.3(0x1999999a), %bb.4(0x1999999a), %bb.5(0x1999999a), %bb.6(0x1999999a)

%14:gr64 = LEA64r $rip, 1, $noreg, %jump-table.0, $noreg
%15:gr64 = MOVSX64rm32 %8, 4, %8, 0, $noreg :: (load (s32) from jump-table)
%16:gr64 = ADD64rr %14, killed %15, implicit-def dead $eflags
JMP64r killed %16

bb.2:
ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
CALL64pcrel32 target-flags(x86-plt) @f1, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
%13:gr64 = COPY $rax
%2:gr64 = COPY %13
JMP_1 %bb.1

bb.3:
ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
CALL64pcrel32 target-flags(x86-plt) @f2, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
%12:gr64 = COPY $rax
%3:gr64 = COPY %12
JMP_1 %bb.1

bb.4:
ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
CALL64pcrel32 target-flags(x86-plt) @f3, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
%11:gr64 = COPY $rax
%4:gr64 = COPY %11
JMP_1 %bb.1

bb.5:
ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
CALL64pcrel32 target-flags(x86-plt) @f4, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
%10:gr64 = COPY $rax
%5:gr64 = COPY %10
JMP_1 %bb.1

bb.6:
ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
CALL64pcrel32 target-flags(x86-plt) @f5, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
%9:gr64 = COPY $rax
%6:gr64 = COPY %9
JMP_1 %bb.1

bb.7:

...