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More IT instruction error-handling improvements from fuzzing.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101839 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Johnny Chen
2010-04-20 00:15:41 +00:00
parent 68b7960c1a
commit 6bcf52f00a
1 changed files with 17 additions and 3 deletions
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20
lib/Target/ARM/Disassembler/ARMDisassembler.cpp
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@ -513,7 +513,7 @@ static unsigned short CountITSize(unsigned ITMask) {
// First count the trailing zeros of the IT mask. // First count the trailing zeros of the IT mask.
unsigned TZ = CountTrailingZeros_32(ITMask); unsigned TZ = CountTrailingZeros_32(ITMask);
if (TZ > 3) { if (TZ > 3) {
DEBUG(errs() << "Encoding error of IT mask"); DEBUG(errs() << "Encoding error: IT Mask '0000'");
return 0; return 0;
} }
return (4 - TZ); return (4 - TZ);
@ -522,9 +522,23 @@ static unsigned short CountITSize(unsigned ITMask) {
/// Init ITState. Note that at least one bit is always 1 in mask. /// Init ITState. Note that at least one bit is always 1 in mask.
bool Session::InitIT(unsigned short bits7_0) { bool Session::InitIT(unsigned short bits7_0) {
ITCounter = CountITSize(slice(bits7_0, 3, 0)); ITCounter = CountITSize(slice(bits7_0, 3, 0));
if (ITCounter == 0)
return false;
// A8.6.50 IT
unsigned short FirstCond = slice(bits7_0, 7, 4);
if (FirstCond == 0xF) {
DEBUG(errs() << "Encoding error: IT FirstCond '1111'");
return false;
}
if (FirstCond == 0xE && ITCounter != 1) {
DEBUG(errs() << "Encoding error: IT FirstCond '1110' && Mask != '1000'");
return false;
}
ITState = bits7_0; ITState = bits7_0;
// Only need to check for > 0.
return ITCounter > 0; return true;
} }
/// Update ITState if necessary. /// Update ITState if necessary.