Add a funciton 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 informing
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170095 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 18 insertions, 4 deletions

diff --git a/tools/llvm-objdump/MachODump.cpp b/tools/llvm-objdump/MachODump.cpp
index 3a350382ae1..c324ff13a6b 100644
--- a/tools/llvm-objdump/MachODump.cpp
+++ b/tools/llvm-objdump/MachODump.cpp
@@ -334,9 +334,15 @@ void llvm::DisassembleInputMachO(StringRef Filename) {
   for (unsigned SectIdx = 0; SectIdx != Sections.size(); SectIdx++) {
     StringRef SectName;
     if (Sections[SectIdx].getName(SectName) ||
-        SectName.compare("__TEXT,__text"))
+        SectName != "__text")
       continue; // Skip non-text sections
 
+    StringRef SegmentName;
+    DataRefImpl DR = Sections[SectIdx].getRawDataRefImpl();
+    if (MachOOF->getSectionFinalSegmentName(DR, SegmentName) ||
+        SegmentName != "__TEXT")
+      continue;
+
     // Insert the functions from the function starts segment into our map.
     uint64_t VMAddr;
     Sections[SectIdx].getAddress(VMAddr);
diff --git a/tools/llvm-objdump/llvm-objdump.cpp b/tools/llvm-objdump/llvm-objdump.cpp
index 2838a2a2b30..9edcae8d6b3 100644
--- a/tools/llvm-objdump/llvm-objdump.cpp
+++ b/tools/llvm-objdump/llvm-objdump.cpp
@@ -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, "
@@ -567,6 +568,13 @@ 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 +648,7 @@ static void DumpInput(StringRef file) {
     return;
   }
 
-  if (MachO && Disassemble) {
+  if (MachOOpt && Disassemble) {
     DisassembleInputMachO(file);
     return;
   }