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.

llvm-svn: 170095

1 files changed, 25 insertions, 10 deletions

diff --git a/llvm/lib/Object/MachOObjectFile.cpp b/llvm/lib/Object/MachOObjectFile.cpp
index a38fac78aae..392563ad194 100644
--- a/llvm/lib/Object/MachOObjectFile.cpp
+++ b/llvm/lib/Object/MachOObjectFile.cpp
@@ -473,28 +473,43 @@ static bool is64BitLoadCommand(const MachOObject *MachOObj, DataRefImpl DRI) {
   return false;
 }
 
+static StringRef parseSegmentOrSectionName(const char *P) {
+  if (P[15] == 0)
+    // Null terminated.
+    return P;
+  // Not null terminated, so this is a 16 char string.
+  return StringRef(P, 16);
+}
+
 error_code MachOObjectFile::getSectionName(DataRefImpl DRI,
                                            StringRef &Result) const {
-  // FIXME: thread safety.
-  static char result[34];
   if (is64BitLoadCommand(MachOObj.get(), DRI)) {
     LoadCommandInfo LCI = MachOObj->getLoadCommandInfo(DRI.d.a);
     InMemoryStruct<macho::Section64> Sect;
     MachOObj->ReadSection64(LCI, DRI.d.b, Sect);
-
-    strcpy(result, Sect->SegmentName);
-    strcat(result, ",");
-    strcat(result, Sect->Name);
+    Result = parseSegmentOrSectionName(Sect->Name);
   } else {
     LoadCommandInfo LCI = MachOObj->getLoadCommandInfo(DRI.d.a);
     InMemoryStruct<macho::Section> Sect;
     MachOObj->ReadSection(LCI, DRI.d.b, Sect);
+    Result = parseSegmentOrSectionName(Sect->Name);
+  }
+  return object_error::success;
+}
 
-    strcpy(result, Sect->SegmentName);
-    strcat(result, ",");
-    strcat(result, Sect->Name);
+error_code MachOObjectFile::getSectionFinalSegmentName(DataRefImpl Sec,
+                                                       StringRef &Res) const {
+  if (is64BitLoadCommand(MachOObj.get(), Sec)) {
+    LoadCommandInfo LCI = MachOObj->getLoadCommandInfo(Sec.d.a);
+    InMemoryStruct<macho::Section64> Sect;
+    MachOObj->ReadSection64(LCI, Sec.d.b, Sect);
+    Res = parseSegmentOrSectionName(Sect->SegmentName);
+  } else {
+    LoadCommandInfo LCI = MachOObj->getLoadCommandInfo(Sec.d.a);
+    InMemoryStruct<macho::Section> Sect;
+    MachOObj->ReadSection(LCI, Sec.d.b, Sect);
+    Res = parseSegmentOrSectionName(Sect->SegmentName);
   }
-  Result = StringRef(result);
   return object_error::success;
 }