[llvm-commits] [llvm] r101201 - in /llvm/trunk/lib/Target/ARM/Disassembler: ARMDisassemblerCore.cpp ARMDisassemblerCore.h

[Johnny Chen]

Author: johnny
Date: Tue Apr 13 20:17:37 2010
New Revision: 101201

URL: http://llvm.org/viewvc/llvm-project?rev=101201&view=rev
Log:
Fixed an assert() exposed by fuzzing.  Now, instead of assert when an invalid
instruction encoding is encountered, we just return a NULL ARMBasicMCBuilder
instance and the client just returns false to indicate disassembly error.

Modified:
    llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
    llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.h

Modified: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp?rev=101201&r1=101200&r2=101201&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp Tue Apr 13 20:17:37 2010
@@ -3257,6 +3257,9 @@
 /// are responsible for freeing up of the allocated memory.  Cacheing can be
 /// performed by the API clients to improve performance.
 ARMBasicMCBuilder *llvm::CreateMCBuilder(unsigned Opcode, ARMFormat Format) {
+  // For "Unknown format", fail by returning a NULL pointer.
+  if ((unsigned)Format >= (array_lengthof(FuncPtrs) - 1))
+    return 0;
 
   return new ARMBasicMCBuilder(Opcode, Format,
                                ARMInsts[Opcode].getNumOperands());

Modified: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.h?rev=101201&r1=101200&r2=101201&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.h (original)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.h Tue Apr 13 20:17:37 2010
@@ -171,24 +171,33 @@
 typedef bool (*DisassembleFP)(MCInst &MI, unsigned Opcode, uint32_t insn,
     unsigned short NumOps, unsigned &NumOpsAdded, BO Builder);
 
+/// CreateMCBuilder - Return an ARMBasicMCBuilder that can build up the MC
+/// infrastructure of an MCInst given the Opcode and Format of the instr.
+/// Return NULL if it fails to create/return a proper builder.  API clients
+/// are responsible for freeing up of the allocated memory.  Cacheing can be
+/// performed by the API clients to improve performance.
+extern ARMBasicMCBuilder *CreateMCBuilder(unsigned Opcode, ARMFormat Format);
+
 /// ARMBasicMCBuilder - ARMBasicMCBuilder represents an ARM MCInst builder that
 /// knows how to build up the MCOperand list.
 class ARMBasicMCBuilder {
+  friend ARMBasicMCBuilder *CreateMCBuilder(unsigned Opcode, ARMFormat Format);
   unsigned Opcode;
   ARMFormat Format;
   unsigned short NumOps;
   DisassembleFP Disasm;
   Session *SP;
 
+private:
+  /// Opcode, Format, and NumOperands make up an ARM Basic MCBuilder.
+  ARMBasicMCBuilder(unsigned opc, ARMFormat format, unsigned short num);
+
 public:
   ARMBasicMCBuilder(ARMBasicMCBuilder &B)
     : Opcode(B.Opcode), Format(B.Format), NumOps(B.NumOps), Disasm(B.Disasm),
       SP(B.SP)
   {}
 
-  /// Opcode, Format, and NumOperands make up an ARM Basic MCBuilder.
-  ARMBasicMCBuilder(unsigned opc, ARMFormat format, unsigned short num);
-
   virtual ~ARMBasicMCBuilder() {}
 
   void setSession(Session *sp) {
@@ -236,13 +245,6 @@
   }
 };
 
-/// CreateMCBuilder - Return an ARMBasicMCBuilder that can build up the MC
-/// infrastructure of an MCInst given the Opcode and Format of the instr.
-/// Return NULL if it fails to create/return a proper builder.  API clients
-/// are responsible for freeing up of the allocated memory.  Cacheing can be
-/// performed by the API clients to improve performance.
-extern ARMBasicMCBuilder *CreateMCBuilder(unsigned Opcode, ARMFormat Format);
-
 } // namespace llvm
 
 #endif