llvm_mode/split-switches-pass: add checks
Add extra check to allow early exist in trivial cases that would
sometimes lead to crashes.
MODIFY
llvm_mode/split-switches-pass.so.cc
llvm_mode/split-switches-pass.so.cc
@@ -87,6 +87,7 @@ BasicBlock* SplitSwitchesTransform::switchConvert(CaseVector Cases, std::vector<
std::vector<uint8_t> setSizes;
std::vector<std::set<uint8_t>> byteSets(BytesInValue, std::set<uint8_t>());
+ assert(ValTypeBitWidth >= 8 && ValTypeBitWidth <= 64);
/* for each of the possible cases we iterate over all bytes of the values
* build a set of possible values at each byte position in byteSets */
@@ -98,6 +99,8 @@ BasicBlock* SplitSwitchesTransform::switchConvert(CaseVector Cases, std::vector<
}
}
+ /* find the index of the first byte position that was not yet checked. then
+ * save the number of possible values at that byte position */
unsigned smallestIndex = 0;
unsigned smallestSize = 257;
for(unsigned i = 0; i < byteSets.size(); i++) {
@@ -235,9 +238,13 @@ bool SplitSwitchesTransform::splitSwitches(Module &M) {
/* this is the value we are switching on */
Value *Val = SI->getCondition();
BasicBlock* Default = SI->getDefaultDest();
+ unsigned bitw = Val->getType()->getIntegerBitWidth();
- /* If there is only the default destination, don't bother with the code below. */
- if (!SI->getNumCases()) {
+ errs() << "switch: " << SI->getNumCases() << " cases " << bitw << " bit\n";
+
+ /* If there is only the default destination or the condition checks 8 bit or less, don't bother with the code below. */
+ if (!SI->getNumCases() || bitw <= 8) {
+ errs() << "skip trivial switch..\n";
continue;
}

llvm_mode/split-switches-pass: add checks

Add extra check to allow early exist in trivial cases that would
sometimes lead to crashes.