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Move the STT_FILE symbols out of the normal symbol table processing for 

ELF. They can overlap with the other symbols, e.g. if a source file
"foo.c" contains a function "foo" with a static variable "c".

llvm-svn: 193569
This commit is contained in:
Joerg Sonnenberger 2013-10-29 01:06:17 +00:00
parent 4a841a86bd
commit fc18473400
5 changed files with 101 additions and 22 deletions
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21
llvm/include/llvm/MC/MCAssembler.h
View File

@ -19,6 +19,7 @@
#include "llvm/MC/MCInst.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/DataTypes.h"
#include <algorithm>
#include <vector> // FIXME: Shouldn't be needed.
namespace llvm {
@ -816,6 +817,9 @@ public:
typedef SymbolDataListType::const_iterator const_symbol_iterator;
typedef SymbolDataListType::iterator symbol_iterator;
typedef std::vector<std::string> FileNameVectorType;
typedef FileNameVectorType::const_iterator const_file_name_iterator;
typedef std::vector<IndirectSymbolData>::const_iterator
const_indirect_symbol_iterator;
typedef std::vector<IndirectSymbolData>::iterator indirect_symbol_iterator;
@ -859,6 +863,9 @@ private:
/// The list of linker options to propagate into the object file.
std::vector<std::vector<std::string> > LinkerOptions;
/// List of declared file names
FileNameVectorType FileNames;
/// The set of function symbols for which a .thumb_func directive has
/// been seen.
//
@ -1152,6 +1159,20 @@ public:
return *Entry;
}
const_file_name_iterator file_names_begin() const {
return FileNames.begin();
}
const_file_name_iterator file_names_end() const {
return FileNames.end();
}
void addFileName(StringRef FileName) {
if (std::find(file_names_begin(), file_names_end(), FileName) ==
file_names_end())
FileNames.push_back(FileName);
}
/// @}
void dump();

34
llvm/lib/MC/ELFObjectWriter.cpp
View File

@ -73,10 +73,6 @@ class ELFObjectWriter : public MCObjectWriter {
// Support lexicographic sorting.
bool operator<(const ELFSymbolData &RHS) const {
if (MCELF::GetType(*SymbolData) == ELF::STT_FILE)
return true;
if (MCELF::GetType(*RHS.SymbolData) == ELF::STT_FILE)
return false;
return SymbolData->getSymbol().getName() <
RHS.SymbolData->getSymbol().getName();
}
@ -98,6 +94,7 @@ class ELFObjectWriter : public MCObjectWriter {
/// @{
SmallString<256> StringTable;
std::vector<uint64_t> FileSymbolData;
std::vector<ELFSymbolData> LocalSymbolData;
std::vector<ELFSymbolData> ExternalSymbolData;
std::vector<ELFSymbolData> UndefinedSymbolData;
@ -551,7 +548,7 @@ void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF,
uint8_t Type = MCELF::GetType(Data);
uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift);
// Other and Visibility share the same byte with Visability using the lower
// Other and Visibility share the same byte with Visibility using the lower
// 2 bits
uint8_t Visibility = MCELF::GetVisibility(OrigData);
uint8_t Other = MCELF::getOther(OrigData) <<
@ -590,8 +587,15 @@ void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF,
// The first entry is the undefined symbol entry.
WriteSymbolEntry(SymtabF, ShndxF, 0, 0, 0, 0, 0, 0, false);
for (unsigned i = 0, e = FileSymbolData.size(); i != e; ++i) {
WriteSymbolEntry(SymtabF, ShndxF, FileSymbolData[i],
ELF::STT_FILE | ELF::STB_LOCAL, 0, 0,
ELF::STV_DEFAULT, ELF::SHN_ABS, true);
}
// Write the symbol table entries.
LastLocalSymbolIndex = LocalSymbolData.size() + 1;
LastLocalSymbolIndex = FileSymbolData.size() + LocalSymbolData.size() + 1;
for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
ELFSymbolData &MSD = LocalSymbolData[i];
WriteSymbol(SymtabF, ShndxF, MSD, Layout);
@ -880,6 +884,20 @@ void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
// FIXME: We could optimize suffixes in strtab in the same way we
// optimize them in shstrtab.
for (MCAssembler::const_file_name_iterator it = Asm.file_names_begin(),
ie = Asm.file_names_end();
it != ie;
++it) {
StringRef Name = *it;
uint64_t &Entry = StringIndexMap[Name];
if (!Entry) {
Entry = StringTable.size();
StringTable += Name;
StringTable += '\x00';
}
FileSymbolData.push_back(Entry);
}
// Add the data for the symbols.
for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
ie = Asm.symbol_end(); it != ie; ++it) {
@ -964,7 +982,7 @@ void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
// Set the symbol indices. Local symbols must come before all other
// symbols with non-local bindings.
unsigned Index = 1;
unsigned Index = FileSymbolData.size() + 1;
for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
LocalSymbolData[i].SymbolData->setIndex(Index++);
@ -1073,7 +1091,7 @@ void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm,
else if (entry.Index < 0)
entry.Index = getSymbolIndexInSymbolTable(Asm, entry.Symbol);
else
entry.Index += LocalSymbolData.size();
entry.Index += FileSymbolData.size() + LocalSymbolData.size();
if (is64Bit()) {
String64(*F, entry.r_offset);
if (TargetObjectWriter->isN64()) {

7
llvm/lib/MC/MCELF.cpp
View File

@ -36,8 +36,8 @@ unsigned MCELF::GetBinding(const MCSymbolData &SD) {
void MCELF::SetType(MCSymbolData &SD, unsigned Type) {
assert(Type == ELF::STT_NOTYPE || Type == ELF::STT_OBJECT ||
Type == ELF::STT_FUNC || Type == ELF::STT_SECTION ||
Type == ELF::STT_FILE || Type == ELF::STT_COMMON ||
Type == ELF::STT_TLS || Type == ELF::STT_GNU_IFUNC);
Type == ELF::STT_COMMON || Type == ELF::STT_TLS ||
Type == ELF::STT_GNU_IFUNC);
uint32_t OtherFlags = SD.getFlags() & ~(0xf << ELF_STT_Shift);
SD.setFlags(OtherFlags | (Type << ELF_STT_Shift));
@ -47,8 +47,7 @@ unsigned MCELF::GetType(const MCSymbolData &SD) {
uint32_t Type = (SD.getFlags() & (0xf << ELF_STT_Shift)) >> ELF_STT_Shift;
assert(Type == ELF::STT_NOTYPE || Type == ELF::STT_OBJECT ||
Type == ELF::STT_FUNC || Type == ELF::STT_SECTION ||
Type == ELF::STT_FILE || Type == ELF::STT_COMMON ||
Type == ELF::STT_TLS || Type == ELF::STT_GNU_IFUNC);
Type == ELF::STT_COMMON || Type == ELF::STT_TLS || Type == ELF::STT_GNU_IFUNC);
return Type;
}

14
llvm/lib/MC/MCELFStreamer.cpp
View File

@ -316,17 +316,11 @@ void MCELFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
ValueSize, MaxBytesToEmit);
}
// Add a symbol for the file name of this module. This is the second
// entry in the module's symbol table (the first being the null symbol).
// Add a symbol for the file name of this module. They start after the
// null symbol and don't count as normal symbol, i.e. a non-STT_FILE symbol
// with the same name may appear.
void MCELFStreamer::EmitFileDirective(StringRef Filename) {
MCSymbol *Symbol = getAssembler().getContext().GetOrCreateSymbol(Filename);
Symbol->setSection(*getCurrentSection().first);
Symbol->setAbsolute();
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
SD.setFlags(ELF_STT_File | ELF_STB_Local | ELF_STV_Default);
getAssembler().addFileName(Filename);
}
void MCELFStreamer::EmitIdent(StringRef IdentString) {

47
llvm/test/MC/ELF/file-double.s Normal file
View File

@ -0,0 +1,47 @@
// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -t | FileCheck %s
// Test that a STT_FILE symbol and a symbol of the same name can coexist.
.file "foo.c"
.file "bar.c"
.globl foo.c
foo.c:
.globl bar.c
bar.c:
// CHECK: Symbol {
// CHECK: Name: foo.c (1)
// CHECK-NEXT: Value: 0x0
// CHECK-NEXT: Size: 0
// CHECK-NEXT: Binding: Local
// CHECK-NEXT: Type: File
// CHECK-NEXT: Other: 0
// CHECK-NEXT: Section: (0xFFF1)
// CHECK-NEXT: }
// CHECK: Name: bar.c (7)
// CHECK-NEXT: Value: 0x0
// CHECK-NEXT: Size: 0
// CHECK-NEXT: Binding: Local
// CHECK-NEXT: Type: File
// CHECK-NEXT: Other: 0
// CHECK-NEXT: Section: (0xFFF1)
// CHECK-NEXT: }
// CHECK: Symbol {
// CHECK: Name: bar.c (7)
// CHECK-NEXT: Value: 0x0
// CHECK-NEXT: Size: 0
// CHECK-NEXT: Binding: Global
// CHECK-NEXT: Type: None
// CHECK-NEXT: Other: 0
// CHECK-NEXT: Section: .text (0x1)
// CHECK-NEXT: }
// CHECK: Symbol {
// CHECK: Name: foo.c (1)
// CHECK-NEXT: Value: 0x0
// CHECK-NEXT: Size: 0
// CHECK-NEXT: Binding: Global
// CHECK-NEXT: Type: None
// CHECK-NEXT: Other: 0
// CHECK-NEXT: Section: .text (0x1)
// CHECK-NEXT: }