[PATCH] D71394: llvm-objdump should ignore Mach-O stab symbols for disassembly.

[Michael Trent via Phabricator via llvm-commits]

mtrent updated this revision to Diff 233842.
mtrent added a comment.

Attempt to clarify STAB symbol restriction comment.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71394/new/

https://reviews.llvm.org/D71394

Files:
  llvm/test/tools/llvm-objdump/Inputs/macho-stabs-x86_64
  llvm/test/tools/llvm-objdump/macho-stabs.test
  llvm/tools/llvm-objdump/llvm-objdump.cpp


Index: llvm/tools/llvm-objdump/llvm-objdump.cpp
===================================================================
--- llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -1134,6 +1134,7 @@
   std::map<SectionRef, SectionSymbolsTy> AllSymbols;
   SectionSymbolsTy AbsoluteSymbols;
   const StringRef FileName = Obj->getFileName();
+  const MachOObjectFile *MachO = dyn_cast<const MachOObjectFile>(Obj);
   for (const SymbolRef &Symbol : Obj->symbols()) {
     uint64_t Address = unwrapOrError(Symbol.getAddress(), FileName);
 
@@ -1148,6 +1149,18 @@
         continue;
     }
 
+    // Don't ask a Mach-O STAB symbol for its section unless you know that 
+    // STAB symbol's section field refers to a valid section index. Otherwise
+    // the symbol may error trying to load a section that does not exist.
+    if (MachO) {
+      DataRefImpl SymDRI = Symbol.getRawDataRefImpl();
+      uint8_t NType = (MachO->is64Bit() ?
+                       MachO->getSymbol64TableEntry(SymDRI).n_type:
+                       MachO->getSymbolTableEntry(SymDRI).n_type);
+      if (NType & MachO::N_STAB)
+        continue;
+    }
+
     section_iterator SecI = unwrapOrError(Symbol.getSection(), FileName);
     if (SecI != Obj->section_end())
       AllSymbols[*SecI].emplace_back(Address, Name, SymbolType);
@@ -1244,7 +1257,7 @@
     }
 
     StringRef SegmentName = "";
-    if (const MachOObjectFile *MachO = dyn_cast<const MachOObjectFile>(Obj)) {
+    if (MachO) {
       DataRefImpl DR = Section.getRawDataRefImpl();
       SegmentName = MachO->getSectionFinalSegmentName(DR);
     }
@@ -1804,6 +1817,7 @@
   }
 
   const StringRef FileName = O->getFileName();
+  const MachOObjectFile *MachO = dyn_cast<const MachOObjectFile>(O);
   for (auto I = O->symbol_begin(), E = O->symbol_end(); I != E; ++I) {
     const SymbolRef &Symbol = *I;
     uint64_t Address = unwrapOrError(Symbol.getAddress(), FileName, ArchiveName,
@@ -1813,8 +1827,23 @@
     SymbolRef::Type Type = unwrapOrError(Symbol.getType(), FileName,
                                          ArchiveName, ArchitectureName);
     uint32_t Flags = Symbol.getFlags();
-    section_iterator Section = unwrapOrError(Symbol.getSection(), FileName,
+
+    // Don't ask a Mach-O STAB symbol for its section unless you know that 
+    // STAB symbol's section field refers to a valid section index. Otherwise
+    // the symbol may error trying to load a section that does not exist.
+    bool isSTAB = false;
+    if (MachO) {
+      DataRefImpl SymDRI = Symbol.getRawDataRefImpl();
+      uint8_t NType = (MachO->is64Bit() ?
+                       MachO->getSymbol64TableEntry(SymDRI).n_type:
+                       MachO->getSymbolTableEntry(SymDRI).n_type);
+      if (NType & MachO::N_STAB)
+        isSTAB = true;
+    }
+    section_iterator Section = isSTAB ? O->section_end() :
+                               unwrapOrError(Symbol.getSection(), FileName,
                                              ArchiveName, ArchitectureName);
+
     StringRef Name;
     if (Type == SymbolRef::ST_Debug && Section != O->section_end()) {
       if (Expected<StringRef> NameOrErr = Section->getName())
Index: llvm/test/tools/llvm-objdump/macho-stabs.test
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-objdump/macho-stabs.test
@@ -0,0 +1,2 @@
+# RUN: llvm-objdump --syms %p/Inputs/macho-stabs-x86_64
+# RUN: llvm-objdump -D %p/Inputs/macho-stabs-x86_64


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D71394.233842.patch
Type: text/x-patch
Size: 3505 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20191213/b3b11425/attachment.bin>