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[BOLT] Read .rela.dyn in static non-pie binary #71635

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Merged
merged 2 commits into from
Nov 10, 2023
Merged

[BOLT] Read .rela.dyn in static non-pie binary #71635

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1006708
[BOLT] Read .rela.dyn in static non-pie binary
yota9 Nov 8, 2023
7cd4470
Merge branch 'main' into main
yota9 Nov 9, 2023
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1 change: 1 addition & 0 deletions bolt/include/bolt/Rewrite/RewriteInstance.h
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Expand Up @@ -430,6 +430,7 @@ class RewriteInstance {

/// Common section names.
static StringRef getEHFrameSectionName() { return ".eh_frame"; }
static StringRef getRelaDynSectionName() { return ".rela.dyn"; }

/// An instance of the input binary we are processing, externally owned.
llvm::object::ELFObjectFileBase *InputFile;
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13 changes: 13 additions & 0 deletions bolt/lib/Rewrite/RewriteInstance.cpp
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Expand Up @@ -2217,6 +2217,19 @@ void RewriteInstance::processDynamicRelocations() {
}

// The rest of dynamic relocations - DT_RELA.
// The static executable might have .rela.dyn secion and not have PT_DYNAMIC
if (!DynamicRelocationsSize && BC->IsStaticExecutable) {
ErrorOr<BinarySection &> DynamicRelSectionOrErr =
BC->getUniqueSectionByName(getRelaDynSectionName());
if (DynamicRelSectionOrErr) {
DynamicRelocationsAddress = DynamicRelSectionOrErr->getAddress();
DynamicRelocationsSize = DynamicRelSectionOrErr->getSize();
const SectionRef &SectionRef = DynamicRelSectionOrErr->getSectionRef();
DynamicRelativeRelocationsCount = std::distance(
SectionRef.relocation_begin(), SectionRef.relocation_end());
}
}

if (DynamicRelocationsSize > 0) {
ErrorOr<BinarySection &> DynamicRelSectionOrErr =
BC->getSectionForAddress(*DynamicRelocationsAddress);
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23 changes: 23 additions & 0 deletions bolt/test/AArch64/ifunc.c
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Expand Up @@ -7,6 +7,20 @@
// RUN: llvm-bolt %t.O0.exe -o %t.O0.bolt.exe \
// RUN: --print-disasm --print-only=_start | \
// RUN: FileCheck --check-prefix=O0_CHECK %s
// RUN: llvm-readelf -aW %t.O0.bolt.exe | \
// RUN: FileCheck --check-prefix=REL_CHECK %s

// Non-pie static executable doesn't generate PT_DYNAMIC, check relocation
// is readed successfully and IPLT trampoline has been identified by bolt.
// RUN: %clang %cflags -nostdlib -O3 %s -fuse-ld=lld -no-pie \
// RUN: -o %t.O3_nopie.exe -Wl,-q
// RUN: llvm-readelf -l %t.O3_nopie.exe | \
// RUN: FileCheck --check-prefix=NON_DYN_CHECK %s
// RUN: llvm-bolt %t.O3_nopie.exe -o %t.O3_nopie.bolt.exe \
// RUN: --print-disasm --print-only=_start | \
// RUN: FileCheck --check-prefix=O3_CHECK %s
// RUN: llvm-readelf -aW %t.O3_nopie.bolt.exe | \
// RUN: FileCheck --check-prefix=REL_CHECK %s

// With -O3 direct call is performed on IPLT trampoline. IPLT trampoline
// doesn't have associated symbol. The ifunc symbol has the same address as
Expand All @@ -16,6 +30,8 @@
// RUN: llvm-bolt %t.O3_pie.exe -o %t.O3_pie.bolt.exe \
// RUN: --print-disasm --print-only=_start | \
// RUN: FileCheck --check-prefix=O3_CHECK %s
// RUN: llvm-readelf -aW %t.O3_pie.bolt.exe | \
// RUN: FileCheck --check-prefix=REL_CHECK %s

// Check that IPLT trampoline located in .plt section are normally handled by
// BOLT. The gnu-ld linker doesn't use separate .iplt section.
Expand All @@ -24,10 +40,17 @@
// RUN: llvm-bolt %t.iplt_O3_pie.exe -o %t.iplt_O3_pie.bolt.exe \
// RUN: --print-disasm --print-only=_start | \
// RUN: FileCheck --check-prefix=O3_CHECK %s
// RUN: llvm-readelf -aW %t.iplt_O3_pie.bolt.exe | \
// RUN: FileCheck --check-prefix=REL_CHECK %s

// NON_DYN_CHECK-NOT: DYNAMIC

// O0_CHECK: adr x{{[0-9]+}}, ifoo
// O3_CHECK: b "{{resolver_foo|ifoo}}{{.*}}@PLT"

// REL_CHECK: R_AARCH64_IRELATIVE [[#%x,REL_SYMB_ADDR:]]
// REL_CHECK: [[#REL_SYMB_ADDR]] {{.*}} FUNC {{.*}} resolver_foo

static void foo() {}

static void *resolver_foo(void) { return foo; }
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