[lld] r346893 - [ELF] Make TrapInstr and Filler byte arrays. NFC.
Simon Atanasyan via llvm-commits
llvm-commits at lists.llvm.org
Wed Nov 14 13:05:20 PST 2018
Author: atanasyan
Date: Wed Nov 14 13:05:20 2018
New Revision: 346893
URL: http://llvm.org/viewvc/llvm-project?rev=346893&view=rev
Log:
[ELF] Make TrapInstr and Filler byte arrays. NFC.
The uint32_t type does not clearly convey that these fields are interpreted
in the target endianness. Converting them to byte arrays should make this
more obvious and less error-prone.
Patch by James Clarke
Differential Revision: http://reviews.llvm.org/D54207
Modified:
lld/trunk/ELF/Arch/ARM.cpp
lld/trunk/ELF/Arch/Mips.cpp
lld/trunk/ELF/Arch/PPC64.cpp
lld/trunk/ELF/Arch/X86.cpp
lld/trunk/ELF/Arch/X86_64.cpp
lld/trunk/ELF/OutputSections.cpp
lld/trunk/ELF/OutputSections.h
lld/trunk/ELF/ScriptParser.cpp
lld/trunk/ELF/Target.h
Modified: lld/trunk/ELF/Arch/ARM.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Arch/ARM.cpp?rev=346893&r1=346892&r2=346893&view=diff
==============================================================================
--- lld/trunk/ELF/Arch/ARM.cpp (original)
+++ lld/trunk/ELF/Arch/ARM.cpp Wed Nov 14 13:05:20 2018
@@ -61,7 +61,7 @@ ARM::ARM() {
GotPltEntrySize = 4;
PltEntrySize = 16;
PltHeaderSize = 32;
- TrapInstr = 0xd4d4d4d4;
+ TrapInstr = {0xd4, 0xd4, 0xd4, 0xd4};
NeedsThunks = true;
}
@@ -196,10 +196,10 @@ void ARM::writePltHeader(uint8_t *Buf) c
write32le(Buf + 4, PltData[1] | ((Offset >> 20) & 0xff));
write32le(Buf + 8, PltData[2] | ((Offset >> 12) & 0xff));
write32le(Buf + 12, PltData[3] | (Offset & 0xfff));
- write32le(Buf + 16, TrapInstr); // Pad to 32-byte boundary
- write32le(Buf + 20, TrapInstr);
- write32le(Buf + 24, TrapInstr);
- write32le(Buf + 28, TrapInstr);
+ memcpy(Buf + 16, TrapInstr.data(), 4); // Pad to 32-byte boundary
+ memcpy(Buf + 20, TrapInstr.data(), 4);
+ memcpy(Buf + 24, TrapInstr.data(), 4);
+ memcpy(Buf + 28, TrapInstr.data(), 4);
}
void ARM::addPltHeaderSymbols(InputSection &IS) const {
@@ -248,7 +248,7 @@ void ARM::writePlt(uint8_t *Buf, uint64_
write32le(Buf + 0, PltData[0] | ((Offset >> 20) & 0xff));
write32le(Buf + 4, PltData[1] | ((Offset >> 12) & 0xff));
write32le(Buf + 8, PltData[2] | (Offset & 0xfff));
- write32le(Buf + 12, TrapInstr); // Pad to 16-byte boundary
+ memcpy(Buf + 12, TrapInstr.data(), 4); // Pad to 16-byte boundary
}
void ARM::addPltSymbols(InputSection &IS, uint64_t Off) const {
Modified: lld/trunk/ELF/Arch/Mips.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Arch/Mips.cpp?rev=346893&r1=346892&r2=346893&view=diff
==============================================================================
--- lld/trunk/ELF/Arch/Mips.cpp (original)
+++ lld/trunk/ELF/Arch/Mips.cpp Wed Nov 14 13:05:20 2018
@@ -56,7 +56,7 @@ template <class ELFT> MIPS<ELFT>::MIPS()
NoneRel = R_MIPS_NONE;
PltRel = R_MIPS_JUMP_SLOT;
NeedsThunks = true;
- TrapInstr = 0xefefefef;
+ TrapInstr = {0xef, 0xef, 0xef, 0xef};
if (ELFT::Is64Bits) {
RelativeRel = (R_MIPS_64 << 8) | R_MIPS_REL32;
Modified: lld/trunk/ELF/Arch/PPC64.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Arch/PPC64.cpp?rev=346893&r1=346892&r2=346893&view=diff
==============================================================================
--- lld/trunk/ELF/Arch/PPC64.cpp (original)
+++ lld/trunk/ELF/Arch/PPC64.cpp Wed Nov 14 13:05:20 2018
@@ -230,8 +230,7 @@ PPC64::PPC64() {
// use 0x10000000 as the starting address.
DefaultImageBase = 0x10000000;
- TrapInstr =
- (Config->IsLE == sys::IsLittleEndianHost) ? 0x7fe00008 : 0x0800e07f;
+ write32(TrapInstr.data(), 0x7fe00008);
}
static uint32_t getEFlags(InputFile *File) {
Modified: lld/trunk/ELF/Arch/X86.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Arch/X86.cpp?rev=346893&r1=346892&r2=346893&view=diff
==============================================================================
--- lld/trunk/ELF/Arch/X86.cpp (original)
+++ lld/trunk/ELF/Arch/X86.cpp Wed Nov 14 13:05:20 2018
@@ -60,7 +60,7 @@ X86::X86() {
PltEntrySize = 16;
PltHeaderSize = 16;
TlsGdRelaxSkip = 2;
- TrapInstr = 0xcccccccc; // 0xcc = INT3
+ TrapInstr = {0xcc, 0xcc, 0xcc, 0xcc}; // 0xcc = INT3
// Align to the non-PAE large page size (known as a superpage or huge page).
// FreeBSD automatically promotes large, superpage-aligned allocations.
Modified: lld/trunk/ELF/Arch/X86_64.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Arch/X86_64.cpp?rev=346893&r1=346892&r2=346893&view=diff
==============================================================================
--- lld/trunk/ELF/Arch/X86_64.cpp (original)
+++ lld/trunk/ELF/Arch/X86_64.cpp Wed Nov 14 13:05:20 2018
@@ -67,7 +67,7 @@ template <class ELFT> X86_64<ELFT>::X86_
PltEntrySize = 16;
PltHeaderSize = 16;
TlsGdRelaxSkip = 2;
- TrapInstr = 0xcccccccc; // 0xcc = INT3
+ TrapInstr = {0xcc, 0xcc, 0xcc, 0xcc}; // 0xcc = INT3
// Align to the large page size (known as a superpage or huge page).
// FreeBSD automatically promotes large, superpage-aligned allocations.
Modified: lld/trunk/ELF/OutputSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.cpp?rev=346893&r1=346892&r2=346893&view=diff
==============================================================================
--- lld/trunk/ELF/OutputSections.cpp (original)
+++ lld/trunk/ELF/OutputSections.cpp Wed Nov 14 13:05:20 2018
@@ -25,6 +25,7 @@
using namespace llvm;
using namespace llvm::dwarf;
using namespace llvm::object;
+using namespace llvm::support::endian;
using namespace llvm::ELF;
using namespace lld;
@@ -170,11 +171,12 @@ void OutputSection::sort(llvm::function_
// Fill [Buf, Buf + Size) with Filler.
// This is used for linker script "=fillexp" command.
-static void fill(uint8_t *Buf, size_t Size, uint32_t Filler) {
+static void fill(uint8_t *Buf, size_t Size,
+ const std::array<uint8_t, 4> &Filler) {
size_t I = 0;
for (; I + 4 < Size; I += 4)
- memcpy(Buf + I, &Filler, 4);
- memcpy(Buf + I, &Filler, Size - I);
+ memcpy(Buf + I, Filler.data(), 4);
+ memcpy(Buf + I, Filler.data(), Size - I);
}
// Compress section contents if this section contains debug info.
@@ -235,8 +237,9 @@ template <class ELFT> void OutputSection
// Write leading padding.
std::vector<InputSection *> Sections = getInputSections(this);
- uint32_t Filler = getFiller();
- if (Filler)
+ std::array<uint8_t, 4> Filler = getFiller();
+ bool NonZeroFiller = read32(Filler.data()) != 0;
+ if (NonZeroFiller)
fill(Buf, Sections.empty() ? Size : Sections[0]->OutSecOff, Filler);
parallelForEachN(0, Sections.size(), [&](size_t I) {
@@ -244,7 +247,7 @@ template <class ELFT> void OutputSection
IS->writeTo<ELFT>(Buf);
// Fill gaps between sections.
- if (Filler) {
+ if (NonZeroFiller) {
uint8_t *Start = Buf + IS->OutSecOff + IS->getSize();
uint8_t *End;
if (I + 1 == Sections.size())
@@ -405,12 +408,12 @@ void OutputSection::sortInitFini() {
sort([](InputSectionBase *S) { return getPriority(S->Name); });
}
-uint32_t OutputSection::getFiller() {
+std::array<uint8_t, 4> OutputSection::getFiller() {
if (Filler)
return *Filler;
if (Flags & SHF_EXECINSTR)
return Target->TrapInstr;
- return 0;
+ return {0, 0, 0, 0};
}
template void OutputSection::writeHeaderTo<ELF32LE>(ELF32LE::Shdr *Shdr);
Modified: lld/trunk/ELF/OutputSections.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.h?rev=346893&r1=346892&r2=346893&view=diff
==============================================================================
--- lld/trunk/ELF/OutputSections.h (original)
+++ lld/trunk/ELF/OutputSections.h Wed Nov 14 13:05:20 2018
@@ -17,6 +17,7 @@
#include "lld/Common/LLVM.h"
#include "llvm/MC/StringTableBuilder.h"
#include "llvm/Object/ELF.h"
+#include <array>
namespace lld {
namespace elf {
@@ -94,7 +95,7 @@ public:
Expr SubalignExpr;
std::vector<BaseCommand *> SectionCommands;
std::vector<StringRef> Phdrs;
- llvm::Optional<uint32_t> Filler;
+ llvm::Optional<std::array<uint8_t, 4>> Filler;
ConstraintKind Constraint = ConstraintKind::NoConstraint;
std::string Location;
std::string MemoryRegionName;
@@ -117,7 +118,7 @@ private:
std::vector<uint8_t> ZDebugHeader;
llvm::SmallVector<char, 1> CompressedData;
- uint32_t getFiller();
+ std::array<uint8_t, 4> getFiller();
};
int getPriority(StringRef S);
Modified: lld/trunk/ELF/ScriptParser.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/ScriptParser.cpp?rev=346893&r1=346892&r2=346893&view=diff
==============================================================================
--- lld/trunk/ELF/ScriptParser.cpp (original)
+++ lld/trunk/ELF/ScriptParser.cpp Wed Nov 14 13:05:20 2018
@@ -78,8 +78,8 @@ private:
SymbolAssignment *readSymbolAssignment(StringRef Name);
ByteCommand *readByteCommand(StringRef Tok);
- uint32_t readFill();
- uint32_t parseFill(StringRef Tok);
+ std::array<uint8_t, 4> readFill();
+ std::array<uint8_t, 4> parseFill(StringRef Tok);
bool readSectionDirective(OutputSection *Cmd, StringRef Tok1, StringRef Tok2);
void readSectionAddressType(OutputSection *Cmd);
OutputSection *readOverlaySectionDescription();
@@ -727,9 +727,9 @@ Expr ScriptParser::readAssert() {
// alias for =fillexp section attribute, which is different from
// what GNU linkers do.
// https://sourceware.org/binutils/docs/ld/Output-Section-Data.html
-uint32_t ScriptParser::readFill() {
+std::array<uint8_t, 4> ScriptParser::readFill() {
expect("(");
- uint32_t V = parseFill(next());
+ std::array<uint8_t, 4> V = parseFill(next());
expect(")");
return V;
}
@@ -879,13 +879,13 @@ OutputSection *ScriptParser::readOutputS
// When reading a hexstring, ld.bfd handles it as a blob of arbitrary
// size, while ld.gold always handles it as a 32-bit big-endian number.
// We are compatible with ld.gold because it's easier to implement.
-uint32_t ScriptParser::parseFill(StringRef Tok) {
+std::array<uint8_t, 4> ScriptParser::parseFill(StringRef Tok) {
uint32_t V = 0;
if (!to_integer(Tok, V))
setError("invalid filler expression: " + Tok);
- uint32_t Buf;
- write32be(&Buf, V);
+ std::array<uint8_t, 4> Buf;
+ write32be(Buf.data(), V);
return Buf;
}
Modified: lld/trunk/ELF/Target.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Target.h?rev=346893&r1=346892&r2=346893&view=diff
==============================================================================
--- lld/trunk/ELF/Target.h (original)
+++ lld/trunk/ELF/Target.h Wed Nov 14 13:05:20 2018
@@ -14,6 +14,7 @@
#include "lld/Common/ErrorHandler.h"
#include "llvm/Object/ELF.h"
#include "llvm/Support/MathExtras.h"
+#include <array>
namespace lld {
std::string toString(elf::RelType Type);
@@ -121,7 +122,7 @@ public:
// A 4-byte field corresponding to one or more trap instructions, used to pad
// executable OutputSections.
- uint32_t TrapInstr = 0;
+ std::array<uint8_t, 4> TrapInstr = {0, 0, 0, 0};
// If a target needs to rewrite calls to __morestack to instead call
// __morestack_non_split when a split-stack enabled caller calls a
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