Merge pull request #1293 from Qcloud1223/master

consider multiple uses of heap object
SVF-tools · Dec 20, 2023 · 7d68ccb · 7d68ccb
2 parents af2bdc8 + 9122f3d
commit 7d68ccb
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Showing 4 changed files with 17 additions and 11 deletions.
diff --git a/svf-llvm/include/SVF-LLVM/LLVMUtil.h b/svf-llvm/include/SVF-LLVM/LLVMUtil.h
@@ -225,9 +225,9 @@ const Value* stripAllCasts(const Value* val);
 /// Get the type of the heap allocation
 const Type* getTypeOfHeapAlloc(const Instruction* inst);
 
-/// Return the bitcast instruction which is val's only use site, otherwise
+/// Return the bitcast instruction right next to val, otherwise
 /// return nullptr
-const Value* getUniqueUseViaCastInst(const Value* val);
+const Value* getFirstUseViaCastInst(const Value* val);
 
 /// Return corresponding constant expression, otherwise return nullptr
 //@{

diff --git a/svf-llvm/lib/LLVMUtil.cpp b/svf-llvm/lib/LLVMUtil.cpp
@@ -346,17 +346,23 @@ void LLVMUtil::getPrevInsts(const Instruction* curInst, std::vector<const SVFIns
  * for example, %4 = call align 16 i8* @malloc(i64 10); %5 = bitcast i8* %4 to i32*
  * return %5 whose type is i32* but not %4 whose type is i8*
  */
-const Value* LLVMUtil::getUniqueUseViaCastInst(const Value* val)
+const Value* LLVMUtil::getFirstUseViaCastInst(const Value* val)
 {
     const PointerType * type = SVFUtil::dyn_cast<PointerType>(val->getType());
     assert(type && "this value should be a pointer type!");
-    /// If type is void* (i8*) and val is only used at a bitcast instruction
+    /// If type is void* (i8*) and val is immediately used at a bitcast instruction
     if (IntegerType *IT = SVFUtil::dyn_cast<IntegerType>(getPtrElementType(type)))
     {
-        if (IT->getBitWidth() == 8 && val->getNumUses()==1)
+        if (IT->getBitWidth() == 8)
         {
-            const Use *u = &*val->use_begin();
-            return SVFUtil::dyn_cast<BitCastInst>(u->getUser());
+            const Value *latestUse = nullptr;
+            for (const auto &it : val->uses()) {
+                if (SVFUtil::isa<BitCastInst>(it.getUser()))
+                    latestUse = it.getUser();
+                else
+                    latestUse = nullptr;
+            }
+            return latestUse;
         }
     }
     return nullptr;
@@ -371,7 +377,7 @@ const Type* LLVMUtil::getTypeOfHeapAlloc(const Instruction *inst)
     const SVFInstruction* svfinst = LLVMModuleSet::getLLVMModuleSet()->getSVFInstruction(inst);
     if(SVFUtil::isHeapAllocExtCallViaRet(svfinst))
     {
-        if(const Value* v = getUniqueUseViaCastInst(inst))
+        if(const Value* v = getFirstUseViaCastInst(inst))
         {
             if(const PointerType* newTy = SVFUtil::dyn_cast<PointerType>(v->getType()))
                 type = newTy;

diff --git a/svf-llvm/lib/SVFIRBuilder.cpp b/svf-llvm/lib/SVFIRBuilder.cpp
@@ -1101,7 +1101,7 @@ const Value* SVFIRBuilder::getBaseValueForExtArg(const Value* V)
             const SVFInstruction* svfInst = LLVMModuleSet::getLLVMModuleSet()->getSVFInstruction(cb);
             if (SVFUtil::isHeapAllocExtCallViaRet(svfInst))
             {
-                if (const Value* bitCast = getUniqueUseViaCastInst(cb))
+                if (const Value* bitCast = getFirstUseViaCastInst(cb))
                     return bitCast;
             }
         }

diff --git a/svf-llvm/lib/SymbolTableBuilder.cpp b/svf-llvm/lib/SymbolTableBuilder.cpp
@@ -755,7 +755,7 @@ u32_t SymbolTableBuilder::analyzeHeapAllocByteSize(const Value* val)
  */
 void SymbolTableBuilder::analyzeHeapObjType(ObjTypeInfo* typeinfo, const Value* val)
 {
-    if(const Value* castUse = getUniqueUseViaCastInst(val))
+    if(const Value* castUse = getFirstUseViaCastInst(val))
     {
         typeinfo->setFlag(ObjTypeInfo::HEAP_OBJ);
         typeinfo->resetTypeForHeapStaticObj(
@@ -774,7 +774,7 @@ void SymbolTableBuilder::analyzeHeapObjType(ObjTypeInfo* typeinfo, const Value*
  */
 void SymbolTableBuilder::analyzeStaticObjType(ObjTypeInfo* typeinfo, const Value* val)
 {
-    if(const Value* castUse = getUniqueUseViaCastInst(val))
+    if(const Value* castUse = getFirstUseViaCastInst(val))
     {
         typeinfo->setFlag(ObjTypeInfo::STATIC_OBJ);
         typeinfo->resetTypeForHeapStaticObj(