frontend: llvm: catch arg names using debug info

The current way we extract function names from arguments in LLVM is rarely successful. This is because the names attached to the LLVM Argument objects are empty, likely removed during the compilation process. This adds an option for looking at debug information to spot the right argument name. Ref: #1175 Signed-off-by: David Korczynski <[email protected]>
ossf · Aug 3, 2023 · d9ec830 · d9ec830
1 parent d514a6f
commit d9ec830
Showing 1 changed file with 30 additions and 1 deletion.
diff --git a/frontends/llvm/lib/Transforms/FuzzIntrospector/FuzzIntrospector.cpp b/frontends/llvm/lib/Transforms/FuzzIntrospector/FuzzIntrospector.cpp
@@ -1067,11 +1067,40 @@ FuzzerFunctionWrapper FuzzIntrospector::wrapFunction(Function *F) {
   FuncWrap.ReturnType = resolveTypeName(F->getReturnType());
 
   // Arguments
+  // errs() << "Function:\n";
+  // errs() << FuncWrap.FunctionName << "\n";
   for (auto &A : F->args()) {
     FuncWrap.ArgTypes.push_back(resolveTypeName(A.getType()));
-    FuncWrap.ArgNames.push_back(A.getName().str());
+    //FuncWrap.ArgNames.push_back(A.getName().str());
+    if (A.getName().str().empty()) {
+      const DILocalVariable* Var = NULL;
+      bool FoundArg = false;
+      for (auto &BB : *F) {
+        for (auto &I : BB) {
+          if (const DbgDeclareInst* DbgDeclare = dyn_cast<DbgDeclareInst>(&I)) {
+            if (auto DLV = dyn_cast<DILocalVariable>(DbgDeclare->getVariable())) {
+              if (  DLV->getArg() == A.getArgNo() + 1 &&
+                    !DLV->getName().empty() &&
+                     DLV->getScope()->getSubprogram() == F->getSubprogram()) {
+                //errs() << "--" << DLV->getName().str() << "\n";
+                FuncWrap.ArgNames.push_back(DLV->getName().str());
+                FoundArg = true;
+              }
+            }
+          }
+        }
+      }
+      if (FoundArg == false) {
+        FuncWrap.ArgNames.push_back("");
+      }
+    }
+    else {
+      // It's non empty, we just push that.
+      FuncWrap.ArgNames.push_back(A.getName().str());
+    }
   }
 
+
   // Log the amount of basic blocks, instruction count and cyclomatic
   // complexity of the function.
   FuncWrap.BBCount = 0;