[llvm-readobj] Print MIPS .MIPS.options section content

.MIPS.options section specifies miscellaneous options to be applied
to an object file. LLVM as well as modern versions of GNU tools emit
the only type of the options - ODK_REGINFO. The patch teaches llvm-readobj
to print details of the ODK_REGINFO and skip contents of other options.

llvm-svn: 268478

test/tools/llvm-readobj/mips-options-sec.test

@@ -0,0 +1,12 @@
+RUN: llvm-readobj -mips-options %p/Inputs/options.obj.elf-mipsel | FileCheck %s
+
+CHECK:      MIPS Options {
+CHECK-NEXT:   ODK_REGINFO {
+CHECK-NEXT:     GP: 0x0
+CHECK-NEXT:     General Mask: 0xF2000017
+CHECK-NEXT:     Co-Proc Mask0: 0x0
+CHECK-NEXT:     Co-Proc Mask1: 0x0
+CHECK-NEXT:     Co-Proc Mask2: 0x0
+CHECK-NEXT:     Co-Proc Mask3: 0x0
+CHECK-NEXT:   }
+CHECK-NEXT: }

tools/llvm-readobj/ELFDumper.cpp

@@ -120,6 +120,7 @@ public:
   void printMipsPLTGOT() override;
   void printMipsABIFlags() override;
   void printMipsReginfo() override;
+  void printMipsOptions() override;
 
   void printStackMap() const override;
 
@@ -1214,6 +1215,25 @@ static const EnumEntry<unsigned> ElfMips16SymOtherFlags[] = {
   LLVM_READOBJ_ENUM_ENT(ELF, STO_MIPS_MIPS16)
 };
 
+static const char *getElfMipsOptionsOdkType(unsigned Odk) {
+  switch (Odk) {
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_NULL);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_REGINFO);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_EXCEPTIONS);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_PAD);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_HWPATCH);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_FILL);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_TAGS);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_HWAND);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_HWOR);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_GP_GROUP);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_IDENT);
+  LLVM_READOBJ_ENUM_CASE(ELF, ODK_PAGESIZE);
+  default:
+    return "Unknown";
+  }
+}
+
 template <typename ELFT>
 ELFDumper<ELFT>::ELFDumper(const ELFFile<ELFT> *Obj, ScopedPrinter &Writer)
     : ObjDumper(Writer), Obj(Obj) {
@@ -2187,6 +2207,17 @@ template <class ELFT> void ELFDumper<ELFT>::printMipsABIFlags() {
   W.printHex("Flags 2", Flags->flags2);
 }
 
+template <class ELFT>
+static void printMipsReginfoData(ScopedPrinter &W,
+                                 const Elf_Mips_RegInfo<ELFT> &Reginfo) {
+  W.printHex("GP", Reginfo.ri_gp_value);
+  W.printHex("General Mask", Reginfo.ri_gprmask);
+  W.printHex("Co-Proc Mask0", Reginfo.ri_cprmask[0]);
+  W.printHex("Co-Proc Mask1", Reginfo.ri_cprmask[1]);
+  W.printHex("Co-Proc Mask2", Reginfo.ri_cprmask[2]);
+  W.printHex("Co-Proc Mask3", Reginfo.ri_cprmask[3]);
+}
+
 template <class ELFT> void ELFDumper<ELFT>::printMipsReginfo() {
   const Elf_Shdr *Shdr = findSectionByName(*Obj, ".reginfo");
   if (!Shdr) {
@@ -2199,15 +2230,38 @@ template <class ELFT> void ELFDumper<ELFT>::printMipsReginfo() {
     return;
   }
 
-  auto *Reginfo = reinterpret_cast<const Elf_Mips_RegInfo<ELFT> *>(Sec.data());
-
   DictScope GS(W, "MIPS RegInfo");
-  W.printHex("GP", Reginfo->ri_gp_value);
-  W.printHex("General Mask", Reginfo->ri_gprmask);
-  W.printHex("Co-Proc Mask0", Reginfo->ri_cprmask[0]);
-  W.printHex("Co-Proc Mask1", Reginfo->ri_cprmask[1]);
-  W.printHex("Co-Proc Mask2", Reginfo->ri_cprmask[2]);
-  W.printHex("Co-Proc Mask3", Reginfo->ri_cprmask[3]);
+  auto *Reginfo = reinterpret_cast<const Elf_Mips_RegInfo<ELFT> *>(Sec.data());
+  printMipsReginfoData(W, *Reginfo);
+}
+
+template <class ELFT> void ELFDumper<ELFT>::printMipsOptions() {
+  const Elf_Shdr *Shdr = findSectionByName(*Obj, ".MIPS.options");
+  if (!Shdr) {
+    W.startLine() << "There is no .MIPS.options section in the file.\n";
+    return;
+  }
+
+  DictScope GS(W, "MIPS Options");
+
+  ArrayRef<uint8_t> Sec = unwrapOrError(Obj->getSectionContents(Shdr));
+  while (!Sec.empty()) {
+    if (Sec.size() < sizeof(Elf_Mips_Options<ELFT>)) {
+      W.startLine() << "The .MIPS.options section has a wrong size.\n";
+      return;
+    }
+    auto *O = reinterpret_cast<const Elf_Mips_Options<ELFT> *>(Sec.data());
+    DictScope GS(W, getElfMipsOptionsOdkType(O->kind));
+    switch (O->kind) {
+    case ODK_REGINFO:
+      printMipsReginfoData(W, O->getRegInfo());
+      break;
+    default:
+      W.startLine() << "Unsupported MIPS options tag.\n";
+      break;
+    }
+    Sec = Sec.slice(O->size);
+  }
 }
 
 template <class ELFT> void ELFDumper<ELFT>::printStackMap() const {

tools/llvm-readobj/ObjDumper.h

@@ -52,6 +52,7 @@ public:
   virtual void printMipsPLTGOT() { }
   virtual void printMipsABIFlags() { }
   virtual void printMipsReginfo() { }
+  virtual void printMipsOptions() { }
 
   // Only implemented for PE/COFF.
   virtual void printCOFFImports() { }

tools/llvm-readobj/llvm-readobj.cpp

@@ -168,6 +168,10 @@ namespace opts {
   cl::opt<bool> MipsReginfo("mips-reginfo",
                             cl::desc("Display the MIPS .reginfo section"));
 
+  // -mips-options
+  cl::opt<bool> MipsOptions("mips-options",
+                            cl::desc("Display the MIPS .MIPS.options section"));
+
   // -coff-imports
   cl::opt<bool>
   COFFImports("coff-imports", cl::desc("Display the PE/COFF import table"));
@@ -363,6 +367,8 @@ static void dumpObject(const ObjectFile *Obj) {
         Dumper->printMipsABIFlags();
       if (opts::MipsReginfo)
         Dumper->printMipsReginfo();
+      if (opts::MipsOptions)
+        Dumper->printMipsOptions();
     }
     if (opts::SectionGroups)
       Dumper->printGroupSections();