[AArch64AsmPrinter]Place jump tables into hot/unlikely-prefixed data sections for aarch64 #126018
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
mingmingl-llvm
requested review from
HaohaiWen,
david-xl,
ellishg and
williamweixiao
Contributor
Author
|
cc @Colibrow |
Member
|
@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]>
Contributor
Author
|
Hi folks, a reminder about this change when you have a moment :) thanks! |
david-xl
approved these changes
Apr 7, 2025
williamweixiao
approved these changes
Apr 8, 2025
mingmingl-llvm
added a commit
that referenced
this pull request
Apr 14, 2025
…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.
mingmingl-llvm
changed the base branch from
main
to
users/mingmingl-llvm/spr/nfc
mingmingl-llvm
requested review from
JDevlieghere,
aaupov,
maksfb and
rafaelauler
as code owners
mingmingl-llvm
requested review from
a team,
Endilll,
bcardosolopes,
dcci,
lanza,
nikic and
yota9
as code owners
mingmingl-llvm
changed the base branch from
users/mingmingl-llvm/spr/nfc
to
main
mingmingl-llvm
removed request for
a team,
Endilll,
JDevlieghere,
aaupov,
ayermolo,
bcardosolopes,
dcci,
lanza,
maksfb,
nikic,
rafaelauler and
yota9
Contributor
Author
|
Sorry for the spam! I forgot the change the base branch after merging the main branch. |
llvm-sync bot
pushed a commit
to arm/arm-toolchain
that referenced
this pull request
Apr 14, 2025
…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.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This is a follow-up patch of #125993 to port jump table partitions for aarch64.