[llvm] c766d0c - [NFC][AsmPrinter] Refactor AsmPrinter and AArch64AsmPrinter to prepare for jump table partitions on aarch64 (#125993)
via llvm-commits
llvm-commits at lists.llvm.org
Mon Apr 14 11:08:33 PDT 2025
Author: Mingming Liu
Date: 2025-04-14T11:08:30-07:00
New Revision: c766d0c7321b12db12b3b087941e86df0f1a75d1
URL: https://github.com/llvm/llvm-project/commit/c766d0c7321b12db12b3b087941e86df0f1a75d1
DIFF: https://github.com/llvm/llvm-project/commit/c766d0c7321b12db12b3b087941e86df0f1a75d1.diff
LOG: [NFC][AsmPrinter] Refactor AsmPrinter and AArch64AsmPrinter to prepare for jump table partitions on aarch64 (#125993)
With
https://github.com/llvm/llvm-project/commit/3feb724496238ce10d32e8c2bd84b4ea50f9977e,
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 https://github.com/llvm/llvm-project/pull/125987,
and https://github.com/llvm/llvm-project/pull/126018 implements the port
for aarch64.
Added:
Modified:
llvm/include/llvm/CodeGen/AsmPrinter.h
llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
llvm/test/CodeGen/AArch64/jump-table-partition.ll
Removed:
################################################################################
diff --git a/llvm/include/llvm/CodeGen/AsmPrinter.h b/llvm/include/llvm/CodeGen/AsmPrinter.h
index 16363fbaa4f9a..79d23986f3b43 100644
--- a/llvm/include/llvm/CodeGen/AsmPrinter.h
+++ b/llvm/include/llvm/CodeGen/AsmPrinter.h
@@ -908,9 +908,8 @@ class AsmPrinter : public MachineFunctionPass {
// Internal Implementation Details
//===------------------------------------------------------------------===//
- void emitJumpTableImpl(const MachineJumpTableInfo &MJTI,
- ArrayRef<unsigned> JumpTableIndices,
- bool JTInDiffSection);
+ virtual void emitJumpTableImpl(const MachineJumpTableInfo &MJTI,
+ ArrayRef<unsigned> JumpTableIndices);
void emitJumpTableSizesSection(const MachineJumpTableInfo &MJTI,
const Function &F) const;
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 821879a1f7c36..1d72a1e116ecd 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -2860,22 +2860,12 @@ void AsmPrinter::emitConstantPool() {
void AsmPrinter::emitJumpTableInfo() {
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
if (!MJTI) return;
- if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
+
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
if (JT.empty()) return;
- // Pick the directive to use to print the jump table entries, and switch to
- // the appropriate section.
- const Function &F = MF->getFunction();
- const TargetLoweringObjectFile &TLOF = getObjFileLowering();
- bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
- MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
- MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference64,
- F);
-
if (!TM.Options.EnableStaticDataPartitioning) {
- emitJumpTableImpl(*MJTI, llvm::to_vector(llvm::seq<unsigned>(JT.size())),
- JTInDiffSection);
+ emitJumpTableImpl(*MJTI, llvm::to_vector(llvm::seq<unsigned>(JT.size())));
return;
}
@@ -2891,33 +2881,40 @@ void AsmPrinter::emitJumpTableInfo() {
}
}
- emitJumpTableImpl(*MJTI, HotJumpTableIndices, JTInDiffSection);
- emitJumpTableImpl(*MJTI, ColdJumpTableIndices, JTInDiffSection);
+ emitJumpTableImpl(*MJTI, HotJumpTableIndices);
+ emitJumpTableImpl(*MJTI, ColdJumpTableIndices);
}
void AsmPrinter::emitJumpTableImpl(const MachineJumpTableInfo &MJTI,
- ArrayRef<unsigned> JumpTableIndices,
- bool JTInDiffSection) {
- if (JumpTableIndices.empty())
+ ArrayRef<unsigned> JumpTableIndices) {
+ if (MJTI.getEntryKind() == MachineJumpTableInfo::EK_Inline ||
+ JumpTableIndices.empty())
return;
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
const Function &F = MF->getFunction();
const std::vector<MachineJumpTableEntry> &JT = MJTI.getJumpTables();
MCSection *JumpTableSection = nullptr;
- if (TM.Options.EnableStaticDataPartitioning) {
- JumpTableSection =
- TLOF.getSectionForJumpTable(F, TM, &JT[JumpTableIndices.front()]);
- } else {
- JumpTableSection = TLOF.getSectionForJumpTable(F, TM);
- }
- const DataLayout &DL = MF->getDataLayout();
+ const bool UseLabelDifference =
+ MJTI.getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
+ MJTI.getEntryKind() == MachineJumpTableInfo::EK_LabelDifference64;
+ // Pick the directive to use to print the jump table entries, and switch to
+ // the appropriate section.
+ const bool JTInDiffSection =
+ !TLOF.shouldPutJumpTableInFunctionSection(UseLabelDifference, F);
if (JTInDiffSection) {
+ if (TM.Options.EnableStaticDataPartitioning) {
+ JumpTableSection =
+ TLOF.getSectionForJumpTable(F, TM, &JT[JumpTableIndices.front()]);
+ } else {
+ JumpTableSection = TLOF.getSectionForJumpTable(F, TM);
+ }
OutStreamer->switchSection(JumpTableSection);
}
- emitAlignment(Align(MJTI.getEntryAlignment(MF->getDataLayout())));
+ const DataLayout &DL = MF->getDataLayout();
+ emitAlignment(Align(MJTI.getEntryAlignment(DL)));
// Jump tables in code sections are marked with a data_region directive
// where that's supported.
diff --git a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
index db0652bc5949c..132e962a065e3 100644
--- a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -113,7 +113,8 @@ class AArch64AsmPrinter : public AsmPrinter {
const MCExpr *lowerBlockAddressConstant(const BlockAddress &BA) override;
void emitStartOfAsmFile(Module &M) override;
- void emitJumpTableInfo() override;
+ void emitJumpTableImpl(const MachineJumpTableInfo &MJTI,
+ ArrayRef<unsigned> JumpTableIndices) override;
std::tuple<const MCSymbol *, uint64_t, const MCSymbol *,
codeview::JumpTableEntrySize>
getCodeViewJumpTableInfo(int JTI, const MachineInstr *BranchInstr,
@@ -1290,19 +1291,18 @@ void AArch64AsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
printOperand(MI, NOps - 2, OS);
}
-void AArch64AsmPrinter::emitJumpTableInfo() {
- const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
- if (!MJTI) return;
-
- const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
- if (JT.empty()) return;
-
+void AArch64AsmPrinter::emitJumpTableImpl(const MachineJumpTableInfo &MJTI,
+ ArrayRef<unsigned> JumpTableIndices) {
+ // Fast return if there is nothing to emit to avoid creating empty sections.
+ if (JumpTableIndices.empty())
+ return;
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
MCSection *ReadOnlySec = TLOF.getSectionForJumpTable(MF->getFunction(), TM);
OutStreamer->switchSection(ReadOnlySec);
+ const std::vector<MachineJumpTableEntry> &JT = MJTI.getJumpTables();
auto AFI = MF->getInfo<AArch64FunctionInfo>();
- for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
+ for (unsigned JTI : JumpTableIndices) {
const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
// If this jump table was deleted, ignore it.
diff --git a/llvm/test/CodeGen/AArch64/jump-table-partition.ll b/llvm/test/CodeGen/AArch64/jump-table-partition.ll
index 122bbaef09185..14717d718c146 100644
--- a/llvm/test/CodeGen/AArch64/jump-table-partition.ll
+++ b/llvm/test/CodeGen/AArch64/jump-table-partition.ll
@@ -17,48 +17,29 @@
; DEFAULT: .section .rodata.func_without_profile,"a", at progbits
; DEFAULT: .LJTI1_0:
; DEFAULT: .section .rodata.bar_prefix.bar,"a", at progbits
-; DEFAULT: .LJTI2_0
-
-; RUN: llc -mtriple=aarch64-unknown-linux-gnu -enable-split-machine-functions \
-; RUN: -partition-static-data-sections=true -function-sections=true \
+; DEFAULT: .LJTI2_0
+
+; Test that section names are uniqufied by numbers but not function names with
+; {-function-sections, -unique-section-names=false}. Specifically, @foo jump
+; tables are emitted in two sections, one with unique ID 2 and the other with
+; unique ID 3.
+; RUN: llc -mtriple=aarch64-unknown-linux-gnu -partition-static-data-sections \
+; RUN: -function-sections -unique-section-names=false \
; RUN: -aarch64-enable-atomic-cfg-tidy=false -aarch64-min-jump-table-entries=2 \
-; RUN: -unique-section-names=false %s -o - 2>&1 | FileCheck %s --check-prefixes=NUM,JT
+; RUN: %s -o - 2>&1 | FileCheck %s --check-prefixes=NUM,JT
-; Section names will optionally have `.<func>` if -function-sections is enabled.
-; RUN: llc -mtriple=aarch64-unknown-linux-gnu -enable-split-machine-functions \
-; RUN: -partition-static-data-sections=true -function-sections=true \
+; Section names will optionally have `.<func>` with {-function-sections, -unique-section-names}.
+; RUN: llc -mtriple=aarch64-unknown-linux-gnu -partition-static-data-sections \
+; RUN: -function-sections -unique-section-names \
; RUN: -aarch64-enable-atomic-cfg-tidy=false -aarch64-min-jump-table-entries=2 \
; RUN: %s -o - 2>&1 | FileCheck %s --check-prefixes=FUNC,JT
-; RUN: llc -mtriple=aarch64-unknown-linux-gnu -enable-split-machine-functions \
-; RUN: -partition-static-data-sections=true -function-sections=false \
+; Test that section names won't have `.<func>` with -function-sections=false.
+; RUN: llc -mtriple=aarch64-unknown-linux-gnu -partition-static-data-sections \
+; RUN: -function-sections=false \
; 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", at progbits,unique,2
-; FUNC: .section .rodata.hot.foo,"a", at progbits
-; FUNCLESS: .section .rodata.hot.,"a", at progbits
-; JT: .LJTI0_0:
-; JT: .LJTI0_1:
-; JT: .LJTI0_2:
-; JT: .LJTI0_3:
-
-; func_without_profile doesn't have profiles, so its jumptable doesn't have
-; hotness-based prefix.
-; NUM: .section .rodata,"a", at progbits,unique,4
-; FUNC: .section .rodata.func_without_profile,"a", at progbits
-; FUNCLESS: .section .rodata,"a", at progbits
-; JT: .LJTI1_0:
-
-; @bar doesn't have profile information and it has a section prefix.
-; Tests that its jump tables are placed in sections with function prefixes.
-; NUM: .section .rodata.bar_prefix.,"a", at progbits,unique,
-; FUNC: .section .rodata.bar_prefix.bar
-; FUNCLESS: .section .rodata.bar_prefix.,"a"
-; JT: .LJTI2_0
-
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "aarch64-unknown-linux-gnu"
@@ -71,6 +52,19 @@ 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.
+; NUM: .section .rodata.hot.,"a", at progbits,unique,2
+; FUNC: .section .rodata.hot.foo,"a", at progbits
+; FUNCLESS: .section .rodata.hot.,"a", at progbits
+; JT: .LJTI0_0:
+; JT: .LJTI0_2:
+; NUM: .section .rodata.hot.,"a", at progbits,unique,3
+; FUNC-NOT: .section .rodata.hot.foo
+; FUNCLESS-NOT: .section .rodata.hot.,"a", at progbits
+; JT: .LJTI0_1:
+; JT: .LJTI0_3:
+
; jt0 and jt2 are hot. jt1 and jt3 are cold.
define i32 @foo(i32 %num) !prof !13 {
entry:
@@ -168,6 +162,12 @@ return:
ret i32 %mod3
}
+; @func_without_profile doesn't have profiles, so its jumptable doesn't have
+; hotness-based prefix.
+; NUM: .section .rodata,"a", at progbits,unique,5
+; FUNC: .section .rodata.func_without_profile,"a", at progbits
+; FUNCLESS: .section .rodata,"a", at progbits
+; JT: .LJTI1_0:
define void @func_without_profile(i32 %num) {
entry:
switch i32 %num, label %sw.default [
@@ -191,6 +191,12 @@ sw.epilog:
ret void
}
+; @bar doesn't have profile information and it has a section prefix.
+; Tests that its jump tables are placed in sections with function prefixes.
+; NUM: .section .rodata.bar_prefix.,"a", at progbits,unique,7
+; FUNC: .section .rodata.bar_prefix.bar
+; FUNCLESS: .section .rodata.bar_prefix.,"a"
+; JT: .LJTI2_0
define void @bar(i32 %num) !section_prefix !20 {
entry:
switch i32 %num, label %sw.default [
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