Add a function to get the segment name of a section.

On MachO, sections also have segment names. When a tool looking at a .o file
prints a segment name, this is what they mean. In reality, a .o has only one
anonymous, segment.

This patch adds a MachO only function to fetch that segment name. I named it
getSectionFinalSegmentName since the main use for the name seems to be inform
the linker with segment this section should go to.

The patch also changes MachOObjectFile::getSectionName to return just the
section name instead of computing SegmentName,SectionName.

The main difference from the previous patch is that it doesn't use
InMemoryStruct. It is extremely dangerous: if the endians match it returns
a pointer to the file buffer, if not, it returns a pointer to an internal buffer
that is overwritten in the next API call.

We should change all of this code to use
support::detail::packed_endian_specific_integral like ELF, but since these
functions only handle strings, they work with big and little endian machines
as is.

I have tested this by installing ubuntu 12.10 ppc on qemu, that is why it took
so long :-)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170838 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Rafael Espindola
2012-12-21 03:47:03 +00:00
parent ab37b2c4bb
commit cef81b37c7
4 changed files with 75 additions and 20 deletions

View File

@ -28,6 +28,7 @@
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Object/Archive.h"
#include "llvm/Object/COFF.h"
#include "llvm/Object/MachO.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
@ -72,9 +73,9 @@ static cl::opt<bool>
SymbolTable("t", cl::desc("Display the symbol table"));
static cl::opt<bool>
MachO("macho", cl::desc("Use MachO specific object file parser"));
MachOOpt("macho", cl::desc("Use MachO specific object file parser"));
static cl::alias
MachOm("m", cl::desc("Alias for --macho"), cl::aliasopt(MachO));
MachOm("m", cl::desc("Alias for --macho"), cl::aliasopt(MachOOpt));
cl::opt<std::string>
llvm::TripleName("triple", cl::desc("Target triple to disassemble for, "
@ -241,9 +242,18 @@ static void DisassembleObject(const ObjectFile *Obj, bool InlineRelocs) {
// Sort relocations by address.
std::sort(Rels.begin(), Rels.end(), RelocAddressLess);
StringRef SegmentName = "";
if (const MachOObjectFile *MachO = dyn_cast<const MachOObjectFile>(Obj)) {
DataRefImpl DR = i->getRawDataRefImpl();
if (error(MachO->getSectionFinalSegmentName(DR, SegmentName)))
break;
}
StringRef name;
if (error(i->getName(name))) break;
outs() << "Disassembly of section " << name << ':';
outs() << "Disassembly of section ";
if (!SegmentName.empty())
outs() << SegmentName << ",";
outs() << name << ':';
// If the section has no symbols just insert a dummy one and disassemble
// the whole section.
@ -567,6 +577,13 @@ static void PrintSymbolTable(const ObjectFile *o) {
else if (Section == o->end_sections())
outs() << "*UND*";
else {
if (const MachOObjectFile *MachO = dyn_cast<const MachOObjectFile>(o)) {
StringRef SegmentName;
DataRefImpl DR = Section->getRawDataRefImpl();
if (error(MachO->getSectionFinalSegmentName(DR, SegmentName)))
SegmentName = "";
outs() << SegmentName << ",";
}
StringRef SectionName;
if (error(Section->getName(SectionName)))
SectionName = "";
@ -640,7 +657,7 @@ static void DumpInput(StringRef file) {
return;
}
if (MachO && Disassemble) {
if (MachOOpt && Disassemble) {
DisassembleInputMachO(file);
return;
}