[llvm] r193569 - Move the STT_FILE symbols out of the normal symbol table processing for
Rafael Espíndola
rafael.espindola at gmail.com
Mon Oct 28 18:38:57 PDT 2013
thanks. This was one of the most amusing bugs we had!
On 28 October 2013 21:06, Joerg Sonnenberger <joerg at bec.de> wrote:
> Author: joerg
> Date: Mon Oct 28 20:06:17 2013
> New Revision: 193569
>
> URL: http://llvm.org/viewvc/llvm-project?rev=193569&view=rev
> Log:
> 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".
>
> Added:
> llvm/trunk/test/MC/ELF/file-double.s
> Modified:
> llvm/trunk/include/llvm/MC/MCAssembler.h
> llvm/trunk/lib/MC/ELFObjectWriter.cpp
> llvm/trunk/lib/MC/MCELF.cpp
> llvm/trunk/lib/MC/MCELFStreamer.cpp
>
> Modified: llvm/trunk/include/llvm/MC/MCAssembler.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCAssembler.h?rev=193569&r1=193568&r2=193569&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/MC/MCAssembler.h (original)
> +++ llvm/trunk/include/llvm/MC/MCAssembler.h Mon Oct 28 20:06:17 2013
> @@ -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();
>
> Modified: llvm/trunk/lib/MC/ELFObjectWriter.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/ELFObjectWriter.cpp?rev=193569&r1=193568&r2=193569&view=diff
> ==============================================================================
> --- llvm/trunk/lib/MC/ELFObjectWriter.cpp (original)
> +++ llvm/trunk/lib/MC/ELFObjectWriter.cpp Mon Oct 28 20:06:17 2013
> @@ -73,10 +73,6 @@ class ELFObjectWriter : public MCObjectW
>
> // 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 MCObjectW
> /// @{
>
> 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(MCData
> 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(M
> // 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
> // 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
>
> // 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::WriteRelocationsFr
> 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()) {
>
> Modified: llvm/trunk/lib/MC/MCELF.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCELF.cpp?rev=193569&r1=193568&r2=193569&view=diff
> ==============================================================================
> --- llvm/trunk/lib/MC/MCELF.cpp (original)
> +++ llvm/trunk/lib/MC/MCELF.cpp Mon Oct 28 20:06:17 2013
> @@ -36,8 +36,8 @@ unsigned MCELF::GetBinding(const MCSymbo
> 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 MCSymbolDa
> 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;
> }
>
>
> Modified: llvm/trunk/lib/MC/MCELFStreamer.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCELFStreamer.cpp?rev=193569&r1=193568&r2=193569&view=diff
> ==============================================================================
> --- llvm/trunk/lib/MC/MCELFStreamer.cpp (original)
> +++ llvm/trunk/lib/MC/MCELFStreamer.cpp Mon Oct 28 20:06:17 2013
> @@ -316,17 +316,11 @@ void MCELFStreamer::EmitValueToAlignment
> 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) {
>
> Added: llvm/trunk/test/MC/ELF/file-double.s
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/file-double.s?rev=193569&view=auto
> ==============================================================================
> --- llvm/trunk/test/MC/ELF/file-double.s (added)
> +++ llvm/trunk/test/MC/ELF/file-double.s Mon Oct 28 20:06:17 2013
> @@ -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: }
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
More information about the llvm-commits
mailing list