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Fixed another assert exposed by fuzzing. Now, when an encoding error occurs 

involing getBFCInvMask() where lsb <= msb does not hold true, the disassembler
just returns false, instead of assert, to indicate disassembly error.

llvm-svn: 101205
This commit is contained in:
Johnny Chen 2010-04-14 02:05:29 +00:00
parent b723860aac
commit 48bbf4910e
1 changed files with 14 additions and 4 deletions
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18
llvm/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
View File

@ -15,6 +15,7 @@
#include "ARMDisassemblerCore.h" #include "ARMDisassemblerCore.h"
#include "ARMAddressingModes.h" #include "ARMAddressingModes.h"
#include "llvm/Support/raw_ostream.h"
/// ARMGenInstrInfo.inc - ARMGenInstrInfo.inc contains the static const /// ARMGenInstrInfo.inc - ARMGenInstrInfo.inc contains the static const
/// TargetInstrDesc ARMInsts[] definition and the TargetOperandInfo[]'s /// TargetInstrDesc ARMInsts[] definition and the TargetOperandInfo[]'s
@ -885,14 +886,19 @@ static bool DisassembleBrMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
return false; return false;
} }
static inline uint32_t getBFCInvMask(uint32_t insn) { static inline bool getBFCInvMask(uint32_t insn, uint32_t &mask) {
uint32_t lsb = slice(insn, 11, 7); uint32_t lsb = slice(insn, 11, 7);
uint32_t msb = slice(insn, 20, 16); uint32_t msb = slice(insn, 20, 16);
uint32_t Val = 0; uint32_t Val = 0;
assert(lsb <= msb && "Encoding error: lsb > msb"); if (lsb > msb) {
errs() << "Encoding error: lsb > msb\n";
return false;
}
for (uint32_t i = lsb; i <= msb; ++i) for (uint32_t i = lsb; i <= msb; ++i)
Val |= (1 << i); Val |= (1 << i);
return ~Val; mask = ~Val;
return true;
} }
static inline bool SaturateOpcode(unsigned Opcode) { static inline bool SaturateOpcode(unsigned Opcode) {
@ -982,7 +988,11 @@ static bool DisassembleDPFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
MI.addOperand(MCOperand::CreateReg(Opcode == ARM::BFC ? 0 MI.addOperand(MCOperand::CreateReg(Opcode == ARM::BFC ? 0
: getRegisterEnum(ARM::GPRRegClassID, : getRegisterEnum(ARM::GPRRegClassID,
decodeRm(insn)))); decodeRm(insn))));
MI.addOperand(MCOperand::CreateImm(getBFCInvMask(insn))); uint32_t mask = 0;
if (!getBFCInvMask(insn, mask))
return false;
MI.addOperand(MCOperand::CreateImm(mask));
OpIdx += 2; OpIdx += 2;
return true; return true;
} }