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[AArch64AsmPrinter]Place jump tables into hot/unlikely-prefixed data sections for aarch64 #126018

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Merged
merged 9 commits into from
Apr 14, 2025
Merged

[AArch64AsmPrinter]Place jump tables into hot/unlikely-prefixed data sections for aarch64 #126018

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fb2e048
[NFC][Test]Add a test case for aarch64 jump table sections
mingmingl-llvm Feb 6, 2025
a5e6552
remove requires and stat
mingmingl-llvm Feb 6, 2025
169486b
[nfc]asm printer jump table
mingmingl-llvm Feb 6, 2025
acc7e25
rebase on top of precommit test
mingmingl-llvm Feb 6, 2025
bbec612
Fast return in aarch64 impl
mingmingl-llvm Feb 6, 2025
eaa5fd5
code style
mingmingl-llvm Feb 6, 2025
bcd1e15
[AArch64AsmPrinter]Place jump tables into hot/unlikely-prefixed secti…
mingmingl-llvm Feb 6, 2025
0c0b21d
Update llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
mingmingl-llvm Feb 6, 2025
6e19de8
run 'git merge main' and resolve conflicts
mingmingl-llvm Apr 14, 2025
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12 changes: 10 additions & 2 deletions llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1297,10 +1297,18 @@ void AArch64AsmPrinter::emitJumpTableImpl(const MachineJumpTableInfo &MJTI,
if (JumpTableIndices.empty())
return;
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
MCSection *ReadOnlySec = TLOF.getSectionForJumpTable(MF->getFunction(), TM);
const auto &F = MF->getFunction();
ArrayRef<MachineJumpTableEntry> JT = MJTI.getJumpTables();

MCSection *ReadOnlySec = nullptr;
if (TM.Options.EnableStaticDataPartitioning) {
ReadOnlySec =
TLOF.getSectionForJumpTable(F, TM, &JT[JumpTableIndices.front()]);
} else {
ReadOnlySec = TLOF.getSectionForJumpTable(F, TM);
}
OutStreamer->switchSection(ReadOnlySec);

const std::vector<MachineJumpTableEntry> &JT = MJTI.getJumpTables();
auto AFI = MF->getInfo<AArch64FunctionInfo>();
for (unsigned JTI : JumpTableIndices) {
const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
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11 changes: 6 additions & 5 deletions llvm/test/CodeGen/AArch64/jump-table-partition.ll
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Expand Up @@ -52,16 +52,17 @@ target triple = "aarch64-unknown-linux-gnu"
@default = private constant [8 x i8] c"default\00"
@jt3 = private constant [4 x i8] c"jt3\00"

; A function's section prefix is used for all jump tables of this function.
; @foo is hot so its jump table data section has a hot prefix.
; In function @foo, the 2 switch instructions to jt0.* and jt1.* are placed in
; hot-prefixed sections, and the 2 switch instructions to jt2.* and jt3.* are
; placed in cold-prefixed sections.
; NUM: .section .rodata.hot.,"a",@progbits,unique,2
; FUNC: .section .rodata.hot.foo,"a",@progbits
; FUNCLESS: .section .rodata.hot.,"a",@progbits
; JT: .LJTI0_0:
; JT: .LJTI0_2:
; NUM: .section .rodata.hot.,"a",@progbits,unique,3
; FUNC-NOT: .section .rodata.hot.foo
; FUNCLESS-NOT: .section .rodata.hot.,"a",@progbits
; NUM: .section .rodata.unlikely.,"a",@progbits,unique,3
; FUNC: .section .rodata.unlikely.foo
; FUNCLESS: .section .rodata.unlikely.,"a",@progbits
; JT: .LJTI0_1:
; JT: .LJTI0_3:

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