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[Backport] [BOLT] [AArch64] Handle data at the beginning of a function when disassembling and building CFG.

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xiongzhou4 2023-06-15 21:14:11 +08:00
parent 113bb21561
commit 98f073d7a1
2 changed files with 120 additions and 3 deletions
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109
0001-Backport-Handle-data-at-the-beginning-of-a-function.patch Normal file
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@ -0,0 +1,109 @@
From 963d19d86cca708957055f3072cbe8473c8e52e3 Mon Sep 17 00:00:00 2001
From: xiongzhou4 <xiongzhou4@huawei.com>
Date: Thu, 15 Jun 2023 20:34:42 +0800
Subject: [PATCH] [Backport] [BOLT] [AArch64] Handle data at the beginning of a
function when disassembling and building CFG.
---
bolt/src/BinaryFunction.cpp | 11 +++++++----
bolt/src/BinaryFunction.h | 9 +++++++++
bolt/src/Exceptions.cpp | 2 +-
bolt/test/AArch64/data-at-0-offset.c | 17 +++++++++++++++++
4 files changed, 34 insertions(+), 5 deletions(-)
create mode 100644 bolt/test/AArch64/data-at-0-offset.c
diff --git a/bolt/src/BinaryFunction.cpp b/bolt/src/BinaryFunction.cpp
index 9414b83ad..93de63d3f 100644
--- a/bolt/src/BinaryFunction.cpp
+++ b/bolt/src/BinaryFunction.cpp
@@ -1445,6 +1445,9 @@ add_instruction:
addInstruction(Offset, std::move(Instruction));
}
+ if (uint64_t Offset = getFirstInstructionOffset())
+ Labels[Offset] = BC.Ctx->createNamedTempSymbol();
+
clearList(Relocations);
if (!IsSimple) {
@@ -1987,7 +1990,7 @@ bool BinaryFunction::buildCFG(MCPlusBuilder::AllocatorIdTy AllocatorId) {
return false;
assert(BasicBlocks.empty() && "basic block list should be empty");
- assert((Labels.find(0) != Labels.end()) &&
+ assert((Labels.find(getFirstInstructionOffset()) != Labels.end()) &&
"first instruction should always have a label");
// Create basic blocks in the original layout order:
@@ -2087,9 +2090,9 @@ bool BinaryFunction::buildCFG(MCPlusBuilder::AllocatorIdTy AllocatorId) {
updateOffset(LastInstrOffset);
}
}
- if (Offset == 0) {
- // Add associated CFI pseudos in the first offset (0)
- addCFIPlaceholders(0, InsertBB);
+ if (Offset == getFirstInstructionOffset()) {
+ // Add associated CFI pseudos in the first offset.
+ addCFIPlaceholders(Offset, InsertBB);
}
const bool IsBlockEnd = MIB->isTerminator(Instr);
diff --git a/bolt/src/BinaryFunction.h b/bolt/src/BinaryFunction.h
index a824f3d58..3b435cfb3 100644
--- a/bolt/src/BinaryFunction.h
+++ b/bolt/src/BinaryFunction.h
@@ -967,6 +967,15 @@ public:
return const_cast<BinaryFunction *>(this)->getInstructionAtOffset(Offset);
}
+ /// Return offset for the first instruction. If there is data at the
+ /// beginning of a function then offset of the first instruction could
+ /// be different from 0.
+ uint64_t getFirstInstructionOffset() const {
+ if (Instructions.empty())
+ return 0;
+ return Instructions.begin()->first;
+ }
+
/// Return jump table that covers a given \p Address in memory.
JumpTable *getJumpTableContainingAddress(uint64_t Address) {
auto JTI = JumpTables.upper_bound(Address);
diff --git a/bolt/src/Exceptions.cpp b/bolt/src/Exceptions.cpp
index f73054aa8..0a64e3fca 100644
--- a/bolt/src/Exceptions.cpp
+++ b/bolt/src/Exceptions.cpp
@@ -499,7 +499,7 @@ bool CFIReaderWriter::fillCFIInfoFor(BinaryFunction &Function) const {
Optional<uint64_t> LSDA = CurFDE.getLSDAAddress();
Function.setLSDAAddress(LSDA ? *LSDA : 0);
- uint64_t Offset = 0;
+ uint64_t Offset = Function.getFirstInstructionOffset();
uint64_t CodeAlignment = CurFDE.getLinkedCIE()->getCodeAlignmentFactor();
uint64_t DataAlignment = CurFDE.getLinkedCIE()->getDataAlignmentFactor();
if (CurFDE.getLinkedCIE()->getPersonalityAddress()) {
diff --git a/bolt/test/AArch64/data-at-0-offset.c b/bolt/test/AArch64/data-at-0-offset.c
new file mode 100644
index 000000000..e0c689a19
--- /dev/null
+++ b/bolt/test/AArch64/data-at-0-offset.c
@@ -0,0 +1,17 @@
+// RUN: %clang %cflags -O2 -fPIE -Wl,-q -pie %s -o %t.exe
+// RUN: llvm-bolt %t.exe -o %t.bolt 2>&1 | FileCheck %s
+// CHECK-NOT: BOLT-WARNING: unable to disassemble instruction at offset
+
+void extra_space() {
+ asm volatile(".rept 256\n"
+ " .byte 0xff\n"
+ ".endr\n");
+ return;
+}
+
+int main(int argc, char **argv) {
+ void (*fn)(void);
+ fn = extra_space + 256;
+ fn();
+ return 0;
+}
--
2.33.0

14
llvm-bolt.spec
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@ -1,13 +1,15 @@
Name: llvm-bolt
Version: 0
Release: 1.20211016.gitb72f753
Release: 2.20211016.gitb72f753
Summary: BOLT is a post-link optimizer developed to speed up large applications
License: Apache 2.0
URL: https://github.com/facebookincubator/BOLT
Source0: %{name}-%{version}.tar.xz
BuildRequires: gcc gcc-c++ cmake ninja-build libstdc++-static chrpath ncurses-devel zlib-devel
Requires: glibc zlib ncurses-libs libstdc++ libgcc
Requires: glibc zlib ncurses-libs libstdc++ libgcc
Patch1: 0001-Backport-Handle-data-at-the-beginning-of-a-function.patch
%description
BOLT is a post-link optimizer developed to speed up large applications.
@ -15,7 +17,7 @@ It achieves the improvements by optimizing application's code layout based
on execution profile gathered by sampling profiler, such as Linux perf tool.
%prep
%setup -q
%autosetup -p1
mkdir -p _build
cd _build
%{__cmake} -G Ninja ../llvm -DCMAKE_BUILD_TYPE=RelWithDebInfo -DLLVM_ENABLE_ASSERTIONS=ON \
@ -54,6 +56,12 @@ chrpath -d %{_bolt_install_dir}/bin/merge-fdata
%attr(-,root,root) %{_bindir}/perf2bolt
%changelog
* Thu Jun 15 2023 Xiong Zhou <xiongzhou4@huawei.com> 0-2.20211016.gitb72f753
- Type:backport
- ID:NA
- SUG:NA
- DESC: Handle data at the beginning of a function when disassembling and building CFG.
* Mon Dec 19 2022 liyancheng <412998149@qq.com> 0-1.20211016.gitb72f753
- Type:fix
- ID:NA