llvm-objdump: deal with invalid ARM encodings slightly better.

Before we printed a warning to stderr and left the actual output stream in a
mess. This tries to print a .long or .short representation of what we saw (as
if there was a data-in-code directive).

This isn't guaranteed to restore synchronization in Thumb-mode (if the invalid
instruction was supposed to be 32-bits, we may be off-by-16 for the rest of the
function). But there's no certain way to deal with that, and it's invalid code
anyway (if the data really wasn't an instruction, the user can add proper
.data_in_code directives if they care)

llvm-svn: 267250

1 files changed, 17 insertions, 7 deletions

diff --git a/llvm/tools/llvm-objdump/MachODump.cpp b/llvm/tools/llvm-objdump/MachODump.cpp
index 7f256cb58fe..71260ee8452 100644
--- a/llvm/tools/llvm-objdump/MachODump.cpp
+++ b/llvm/tools/llvm-objdump/MachODump.cpp
@@ -6034,7 +6034,7 @@ static void DisassembleMachO(StringRef Filename, MachOObjectFile *MachOOF,
     return;
   }
 
-  // Set up thumb disassembler.
+  // Set up separate thumb disassembler if needed.
   std::unique_ptr<const MCRegisterInfo> ThumbMRI;
   std::unique_ptr<const MCAsmInfo> ThumbAsmInfo;
   std::unique_ptr<const MCSubtargetInfo> ThumbSTI;
@@ -6275,8 +6275,11 @@ static void DisassembleMachO(StringRef Filename, MachOObjectFile *MachOOF,
       symbolTableWorked = true;
 
       DataRefImpl Symb = Symbols[SymIdx].getRawDataRefImpl();
-      bool isThumb =
-          (MachOOF->getSymbolFlags(Symb) & SymbolRef::SF_Thumb) && ThumbTarget;
+      bool IsThumb = MachOOF->getSymbolFlags(Symb) & SymbolRef::SF_Thumb;
+
+      // We only need the dedicated Thumb target if there's a real choice
+      // (i.e. we're not targeting M-class) and the function is Thumb.
+      bool UseThumbTarget = IsThumb && ThumbTarget;
 
       outs() << SymName << ":\n";
       DILineInfo lastLine;
@@ -6320,7 +6323,7 @@ static void DisassembleMachO(StringRef Filename, MachOObjectFile *MachOOF,
         raw_svector_ostream Annotations(AnnotationsBytes);
 
         bool gotInst;
-        if (isThumb)
+        if (UseThumbTarget)
           gotInst = ThumbDisAsm->getInstruction(Inst, Size, Bytes.slice(Index),
                                                 PC, DebugOut, Annotations);
         else
@@ -6332,7 +6335,7 @@ static void DisassembleMachO(StringRef Filename, MachOObjectFile *MachOOF,
           }
           formatted_raw_ostream FormattedOS(outs());
           StringRef AnnotationsStr = Annotations.str();
-          if (isThumb)
+          if (UseThumbTarget)
             ThumbIP->printInst(&Inst, FormattedOS, AnnotationsStr, *ThumbSTI);
           else
             IP->printInst(&Inst, FormattedOS, AnnotationsStr, *STI);
@@ -6354,14 +6357,21 @@ static void DisassembleMachO(StringRef Filename, MachOObjectFile *MachOOF,
             outs() << format("\t.byte 0x%02x #bad opcode\n",
                              *(Bytes.data() + Index) & 0xff);
             Size = 1; // skip exactly one illegible byte and move on.
-          } else if (Arch == Triple::aarch64) {
+          } else if (Arch == Triple::aarch64 ||
+                     (Arch == Triple::arm && !IsThumb)) {
             uint32_t opcode = (*(Bytes.data() + Index) & 0xff) |
                               (*(Bytes.data() + Index + 1) & 0xff) << 8 |
                               (*(Bytes.data() + Index + 2) & 0xff) << 16 |
                               (*(Bytes.data() + Index + 3) & 0xff) << 24;
             outs() << format("\t.long\t0x%08x\n", opcode);
             Size = 4;
-          } else {
+          } else if (Arch == Triple::arm) {
+            assert(IsThumb && "ARM mode should have been dealt with above");
+            uint32_t opcode = (*(Bytes.data() + Index) & 0xff) |
+                              (*(Bytes.data() + Index + 1) & 0xff) << 8;
+            outs() << format("\t.short\t0x%04x\n", opcode);
+            Size = 2;
+          } else{
             errs() << "llvm-objdump: warning: invalid instruction encoding\n";
             if (Size == 0)
               Size = 1; // skip illegible bytes