llvm-objdump: Implement --start-address and --stop-address

[khemant]

Summary

Disassembly only part of the file using address specifiers.

Note: The test is a fully baked executable as relocatables do not have addresses. Test exercises disassembly across symbols, sections and range within a symbol (including data).

[compnerd]

Thoughts on using obj2yaml/yaml2obj on the binary?

test/tools/llvm-objdump/X86/start-stop-address.test

29

Alignment makes reading the output easier, and whitespace is ignored anyways.

tools/llvm-objdump/llvm-objdump.cpp

1529

Why use goto rather than wrap the bit in the if condition?

[khemant]

tools/llvm-objdump/llvm-objdump.cpp

1529

Yea. Even using this goto should have been merged with above goto. I will invert the if condition for both of those cases.

[khemant]

Made test case a yaml instead of binary.

Addressed few comments.

[khemant]

ping..

[compnerd]

Would make it easier to read the test if you aligned the disassembled mnemonics.

test/tools/llvm-objdump/X86/start-stop-address.test

+// RUN: llvm-objdump -d %p/Inputs/simple-executable-x86_64 --start-address=0x18 --stop-address=0x2f | FileCheck %s 
+// RUN: llvm-objdump -d %p/Inputs/simple-executable-x86_64 --start-address=0xc --stop-address=0x11 | FileCheck %s --check-prefix "CROSSSECTION"
+// RUN: llvm-objdump -d %p/Inputs/simple-executable-x86_64 --start-address=0x40 --stop-address=0x47 | FileCheck %s --check-prefix "CROSSDATA"
+
+// CHECK:       Disassembly of section .anothertext:
+// CHECK-NEXT:  main:
+// CHECK-NEXT:        18: 48 8d 04 25 a8 00 00 00   leaq  168, %rax
+// CHECK-NEXT:        20: c7 45 fc 00 00 00 00  movl  $0, -4(%rbp)
+// CHECK-NEXT:        27: 48 89 45 f0   movq  %rax, -16(%rbp)
+// CHECK-NEXT:        2b: 48 8b 45 f0   movq  -16(%rbp), %rax
+// CHECK-NOT:         2f:
+
+// CROSSSECTION:      Disassembly of section .text:
+// CROSSSECTION-NEXT:  foo:
+// CROSSSECTION-NEXT:         c:  c3  retq
+// CROSSSECTION-NEXT:         d:  0f 1f 00  nopl  (%rax)
+// CROSSSECTION-NEXT: Disassembly of section .anothertext:
+// CROSSSECTION-NEXT: main:
+// CROSSSECTION-NEXT:      10:  55  pushq %rbp
+// CROSSSECTION-NOT:       11:
+
+// CROSSDATA:  Disassembly of section .anothertext:
+// CROSSDATA:  main:
+// CROSSDATA:        40:  48 83 c4 20   addq  $32, %rsp
+// CROSSDATA:        44:  5d  popq  %rbp
+
+// CROSSDATA-DAG:   somedata:
+// CROSSDATA-NEXT:        45:  74 65                           te
+

tools/llvm-objdump/llvm-objdump.cpp

cl::alias PrintSourceShort("S", cl::desc("Alias for -source"),
                            cl::aliasopt(PrintSource));
 
 cl::opt<bool> PrintLines("line-numbers",
                          cl::desc("Display source line numbers with "
                                   "disassembly. Implies disassemble object"));
 
 cl::alias PrintLinesShort("l", cl::desc("Alias for -line-numbers"),
                           cl::aliasopt(PrintLines));
+
+cl::opt<unsigned long long>
+    StartAddress("start-address", cl::desc("Disassemble beginning at address"),
+                 cl::value_desc("address"), cl::init(0));
+cl::opt<unsigned long long>
+    StopAddress("stop-address", cl::desc("Stop disassembly at address"),
+                cl::value_desc("address"), cl::init(UINT64_MAX));
 static StringRef ToolName;
 
 namespace {
 typedef std::function<bool(llvm::object::SectionRef const &)> FilterPredicate;
 
 class SectionFilterIterator {
 public:
   SectionFilterIterator(FilterPredicate P,
static uint8_t getElfSymbolType(const ObjectFile *Obj, const SymbolRef &Sym) {
   if (auto *Elf32BEObj = dyn_cast<ELF32BEObjectFile>(Obj))
     return Elf32BEObj->getSymbol(Sym.getRawDataRefImpl())->getType();
   if (auto *Elf64BEObj = cast<ELF64BEObjectFile>(Obj))
     return Elf64BEObj->getSymbol(Sym.getRawDataRefImpl())->getType();
   llvm_unreachable("Unsupported binary format");
 }
 
 static void DisassembleObject(const ObjectFile *Obj, bool InlineRelocs) {
+  if (StartAddress > StopAddress)
+    error("Start address should be less than stop address");
+
   const Target *TheTarget = getTarget(Obj);
 
   // Package up features to be passed to target/subtarget
   SubtargetFeatures Features = Obj->getFeatures();
   if (MAttrs.size()) {
     for (unsigned i = 0; i != MAttrs.size(); ++i)
       Features.AddFeature(MAttrs[i]);
   }
for (const SectionRef &Section : ToolSectionFilter(*Obj)) {
 
     StringRef SegmentName = "";
     if (const MachOObjectFile *MachO = dyn_cast<const MachOObjectFile>(Obj)) {
       DataRefImpl DR = Section.getRawDataRefImpl();
       SegmentName = MachO->getSectionFinalSegmentName(DR);
     }
     StringRef name;
     error(Section.getName(name));
+
+    if ((SectionAddr <= StopAddress) &&
+        (SectionAddr + SectSize) >= StartAddress) {
     outs() << "Disassembly of section ";
     if (!SegmentName.empty())
       outs() << SegmentName << ",";
     outs() << name << ':';
+    }
 
     // If the section has no symbol at the start, just insert a dummy one.
     if (Symbols.empty() || std::get<0>(Symbols[0]) != 0) {
       Symbols.insert(Symbols.begin(),
                      std::make_tuple(SectionAddr, name, Section.isText()
                                                             ? ELF::STT_FUNC
                                                             : ELF::STT_OBJECT));
     }
for (unsigned si = 0, se = Symbols.size(); si != se; ++si) {
           (si == se - 1) ? SectSize : std::get<0>(Symbols[si + 1]) - SectionAddr;
       // Don't try to disassemble beyond the end of section contents.
       if (End > SectSize)
         End = SectSize;
       // If this symbol has the same address as the next symbol, then skip it.
       if (Start >= End)
         continue;
 
+      // Check if we need to skip symbol
+      // Skip if the symbol's data is not between StartAddress and StopAddress
+      if (End + SectionAddr < StartAddress ||
+          Start + SectionAddr > StopAddress) {
+        continue;
+      }
+
+      // Stop disassembly at the stop address specified
+      if (End + SectionAddr > StopAddress)
+        End = StopAddress - SectionAddr;
+
       if (Obj->isELF() && Obj->getArch() == Triple::amdgcn) {
         // make size 4 bytes folded
         End = Start + ((End - Start) & ~0x3ull);
         if (std::get<2>(Symbols[si]) == ELF::STT_AMDGPU_HSA_KERNEL) {
           // skip amd_kernel_code_t at the begining of kernel symbol (256 bytes)
           Start += 256;
         }
         if (si == se - 1 ||
#ifndef NDEBUG
       raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls();
 #else
       raw_ostream &DebugOut = nulls();
 #endif
 
       for (Index = Start; Index < End; Index += Size) {
         MCInst Inst;
 
+        if (Index + SectionAddr < StartAddress ||
+            Index + SectionAddr > StopAddress) {
+          // skip byte by byte till StartAddress is reached
+          Size = 1;
+          continue;
+        }
         // AArch64 ELF binaries can interleave data and text in the
         // same section. We rely on the markers introduced to
         // understand what we need to dump. If the data marker is within a
         // function, it is denoted as a word/short etc
         if (isArmElf(Obj) && std::get<2>(Symbols[si]) != ELF::STT_OBJECT &&
             !DisassembleAll) {
           uint64_t Stride = 0;
 
#endif
         if (Obj->isELF() && std::get<2>(Symbols[si]) == ELF::STT_OBJECT &&
             !DisassembleAll && Section.isText()) {
           // print out data up to 8 bytes at a time in hex and ascii
           uint8_t AsciiData[9] = {'\0'};
           uint8_t Byte;
           int NumBytes = 0;
 
           for (Index = Start; Index < End; Index += 1) {
+            if (((SectionAddr + Index) < StartAddress) ||
+                ((SectionAddr + Index) > StopAddress))
+              continue;
             if (NumBytes == 0) {
               outs() << format("%8" PRIx64 ":", SectionAddr + Index);
               outs() << "\t";
             }
             Byte = Bytes.slice(Index)[0];
             outs() << format(" %02x", Byte);
             AsciiData[NumBytes] = isprint(Byte) ? Byte : '.';
 
#endif
           bool hidden = getHidden(*rel_cur);
           uint64_t addr = rel_cur->getOffset();
           SmallString<16> name;
           SmallString<32> val;
 
           // If this relocation is hidden, skip it.
           if (hidden) goto skip_print_rel;
 
+          if ((SectionAddr + addr) < StartAddress)
+            goto skip_print_rel;
           // Stop when rel_cur's address is past the current instruction.
           if (addr >= Index + Size) break;
           rel_cur->getTypeName(name);
           error(getRelocationValueString(*rel_cur, val));
           outs() << format(Fmt.data(), SectionAddr + addr) << name
                  << "\t" << val << "\n";
 
         skip_print_rel:
for (const SectionRef &Section : ToolSectionFilter(*Obj)) {
     StringRef secname;
     error(Section.getName(secname));
     outs() << "RELOCATION RECORDS FOR [" << secname << "]:\n";
     for (const RelocationRef &Reloc : Section.relocations()) {
       bool hidden = getHidden(Reloc);
       uint64_t address = Reloc.getOffset();
       SmallString<32> relocname;
       SmallString<32> valuestr;
-      if (hidden)
+      if (address < StartAddress || address > StopAddress || hidden)
         continue;
       Reloc.getTypeName(relocname);
       error(getRelocationValueString(Reloc, valuestr));
       outs() << format(Fmt.data(), address) << " " << relocname << " "
              << valuestr << "\n";
     }
     outs() << "\n";
   }
if (const COFFObjectFile *coff = dyn_cast<const COFFObjectFile>(o)) {
     printCOFFSymbolTable(coff);
     return;
   }
   for (const SymbolRef &Symbol : o->symbols()) {
     Expected<uint64_t> AddressOrError = Symbol.getAddress();
     if (!AddressOrError)
       report_error(ArchiveName, o->getFileName(), AddressOrError.takeError());
     uint64_t Address = *AddressOrError;
+    if ((Address < StartAddress) || (Address > StopAddress))
+      continue;
     Expected<SymbolRef::Type> TypeOrError = Symbol.getType();
     if (!TypeOrError)
       report_error(ArchiveName, o->getFileName(), TypeOrError.takeError());
     SymbolRef::Type Type = *TypeOrError;
     uint32_t Flags = Symbol.getFlags();
     Expected<section_iterator> SectionOrErr = Symbol.getSection();
     error(errorToErrorCode(SectionOrErr.takeError()));
     section_iterator Section = *SectionOrErr;