Merge pull request Battelle#6 from pbst/patch

Fix crashes
domenukk · Jun 17, 2019 · d64efa6 · d64efa6
2 parents 0113c4f + 7b5905b
commit d64efa6
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Showing 2 changed files with 16 additions and 9 deletions.
diff --git a/llvm_mode/compare-transform-pass.so.cc b/llvm_mode/compare-transform-pass.so.cc
@@ -184,6 +184,7 @@ bool CompareTransform::transformCmps(Module &M, const bool processStrcmp, const
 
     Value *Str1P = callInst->getArgOperand(0), *Str2P = callInst->getArgOperand(1);
     StringRef Str1, Str2, ConstStr;
+    std::string TmpConstStr;
     Value *VarStr;
     bool HasStr1 = getConstantStringInfo(Str1P, Str1);
     getConstantStringInfo(Str2P, Str2);
@@ -202,21 +203,20 @@ bool CompareTransform::transformCmps(Module &M, const bool processStrcmp, const
     }
 
     if (HasStr1) {
-      ConstStr = Str1;
+      TmpConstStr = Str1.str();
       VarStr = Str2P;
       constLen = isMemcmp ? sizedLen : GetStringLength(Str1P);
     }
     else {
-      ConstStr = Str2;
+      TmpConstStr = Str2.str();
       VarStr = Str1P;
       constLen = isMemcmp ? sizedLen : GetStringLength(Str2P);
     }
 
-    /* bugfix thanks to pbst */
-    /* ignore terminating '\0' in string for strcmp */
-    if (!isSizedcmp && constLen > 0) {
-      constLen--;
-    }
+    /* properly handle zero terminated C strings by adding the terminating 0 to
+     * the StringRef (in comparison to std::string a StringRef has built-in
+     * runtime bounds checking, which makes debugging easier) */
+    TmpConstStr.append("\0", 1); ConstStr = StringRef(TmpConstStr);
 
     if (isSizedcmp && constLen > sizedLen) {
       constLen = sizedLen;

diff --git a/llvm_mode/split-switches-pass.so.cc b/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;
     }