[llvm] [NFC][Fuzzer] Fix zero-size array argv warning (PR #112944)

[Björn Pettersson via llvm-commits]

================
@@ -193,27 +193,27 @@ extern "C" LLVM_ATTRIBUTE_USED int LLVMFuzzerInitialize(int *argc,
 
   // Create TargetMachine
   //
-
+  std::string execName = *argv[0];
----------------
bjope wrote:

I suggest doing something like this instead:

```
diff --git a/llvm/tools/llvm-opt-fuzzer/llvm-opt-fuzzer.cpp b/llvm/tools/llvm-opt-fuzzer/llvm-opt-fuzzer.cpp
index fcccf0e07ef8..8e8e73967e3c 100644
--- a/llvm/tools/llvm-opt-fuzzer/llvm-opt-fuzzer.cpp
+++ b/llvm/tools/llvm-opt-fuzzer/llvm-opt-fuzzer.cpp
@@ -175,6 +175,7 @@ static void handleLLVMFatalError(void *, const char *Message, bool) {
 extern "C" LLVM_ATTRIBUTE_USED int LLVMFuzzerInitialize(int *argc,
                                                         char ***argv) {
   EnableDebugBuffering = true;
+  StringRef ExecName = *argv[0];
 
   // Make sure we print the summary and the current unit when LLVM errors out.
   install_fatal_error_handler(handleLLVMFatalError, nullptr);
@@ -188,17 +189,17 @@ extern "C" LLVM_ATTRIBUTE_USED int LLVMFuzzerInitialize(int *argc,
   // Parse input options
   //
 
-  handleExecNameEncodedOptimizerOpts(*argv[0]);
+  handleExecNameEncodedOptimizerOpts(ExecName);
   parseFuzzerCLOpts(*argc, *argv);
 
   // Create TargetMachine
   //
 
   if (TargetTripleStr.empty()) {
-    errs() << *argv[0] << ": -mtriple must be specified\n";
+    errs() << ExecName << ": -mtriple must be specified\n";
     exit(1);
   }
-  ExitOnError ExitOnErr(std::string(*argv[0]) + ": error:");
+  ExitOnError ExitOnErr(std::string(ExecName) + ": error:");
   TM = ExitOnErr(codegen::createTargetMachineForTriple(
       Triple::normalize(TargetTripleStr)));
 
@@ -206,14 +207,14 @@ extern "C" LLVM_ATTRIBUTE_USED int LLVMFuzzerInitialize(int *argc,
   //
 
   if (PassPipeline.empty()) {
-    errs() << *argv[0] << ": at least one pass should be specified\n";
+    errs() << ExecName << ": at least one pass should be specified\n";
     exit(1);
   }
 
   PassBuilder PB(TM.get());
   ModulePassManager MPM;
   if (auto Err = PB.parsePassPipeline(MPM, PassPipeline)) {
-    errs() << *argv[0] << ": " << toString(std::move(Err)) << "\n";
+    errs() << ExecName << ": " << toString(std::move(Err)) << "\n";
     exit(1);
   }

```

https://github.com/llvm/llvm-project/pull/112944