[AArch64AsmPrinter]Place jump tables into hot/unlikely-prefixed data sections for aarch64 #126018
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@llvm/pr-subscribers-backend-aarch64 Author: Mingming Liu (mingmingl-llvm) ChangesThis is a follow-up patch of #125993 to port jump table partitions for aarch64. Full diff: https://github.com/llvm/llvm-project/pull/126018.diff 2 Files Affected:
diff --git a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
index c92c203f247954..0593c1cd2b14d2 100644
--- a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -1280,10 +1280,18 @@ 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();
+ const std::vector<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;
diff --git a/llvm/test/CodeGen/AArch64/jump-table-partition.ll b/llvm/test/CodeGen/AArch64/jump-table-partition.ll
index e0525d0384a978..d282c366578d70 100644
--- a/llvm/test/CodeGen/AArch64/jump-table-partition.ll
+++ b/llvm/test/CodeGen/AArch64/jump-table-partition.ll
@@ -35,16 +35,17 @@
; RUN: -aarch64-enable-atomic-cfg-tidy=false -aarch64-min-jump-table-entries=2 \
; RUN: %s -o - 2>&1 | FileCheck %s --check-prefixes=FUNCLESS,JT
-; 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.
-; NUM: .section .rodata.hot.,"a",@progbits,unique,2
+; 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:
|
ellishg
reviewed
Feb 6, 2025
Co-authored-by: Ellis Hoag <[email protected]>
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Hi folks, a reminder about this change when you have a moment :) thanks! |
david-xl
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Apr 7, 2025
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Apr 8, 2025
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…e for jump table partitions on aarch64 (#125993) With 3feb724, AsmPrinter can place jump table entries into `.hot` or `.unlikely` prefixed data sections. This change refactors AsmPrinter and AArch64AsmPrinter to prepare for the aarch64 port. * Before this patch, the AsmPrinter class exposes `emitJumpTableInfo` as a virtual method, and AArch64AsmPrinter overrides `emitJumpTableInfo` for jump table emission. * After this patch, both AsmPrinter and AArch64AsmPrinter shares `AsmPrinter::emitJumpTableInfo`, and class-specific code are moved inside each class's `emitJumpTableImpl` respectively. This is a follow-up of #125987, and #126018 implements the port for aarch64.
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…r to prepare for jump table partitions on aarch64 (#125993) With llvm/llvm-project@3feb724, AsmPrinter can place jump table entries into `.hot` or `.unlikely` prefixed data sections. This change refactors AsmPrinter and AArch64AsmPrinter to prepare for the aarch64 port. * Before this patch, the AsmPrinter class exposes `emitJumpTableInfo` as a virtual method, and AArch64AsmPrinter overrides `emitJumpTableInfo` for jump table emission. * After this patch, both AsmPrinter and AArch64AsmPrinter shares `AsmPrinter::emitJumpTableInfo`, and class-specific code are moved inside each class's `emitJumpTableImpl` respectively. This is a follow-up of llvm/llvm-project#125987, and llvm/llvm-project#126018 implements the port for aarch64.
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…e for jump table partitions on aarch64 (llvm#125993) With llvm@3feb724, AsmPrinter can place jump table entries into `.hot` or `.unlikely` prefixed data sections. This change refactors AsmPrinter and AArch64AsmPrinter to prepare for the aarch64 port. * Before this patch, the AsmPrinter class exposes `emitJumpTableInfo` as a virtual method, and AArch64AsmPrinter overrides `emitJumpTableInfo` for jump table emission. * After this patch, both AsmPrinter and AArch64AsmPrinter shares `AsmPrinter::emitJumpTableInfo`, and class-specific code are moved inside each class's `emitJumpTableImpl` respectively. This is a follow-up of llvm#125987, and llvm#126018 implements the port for aarch64.
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…sections for aarch64 (llvm#126018) This is a follow-up patch of llvm#125993 to port jump table partitions for aarch64. --------- Co-authored-by: Ellis Hoag <[email protected]>
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This is a follow-up patch of #125993 to port jump table partitions for aarch64.