[NFC][Fuzzer] Fix zero-size array argv warning

This is one of the many PRs to fix errors with LLVM_ENABLE_WERROR=on. Built by GCC 11.

Fix warning

llvm-project/llvm/tools/llvm-isel-fuzzer/llvm-isel-fuzzer.cpp
llvm-project/llvm/tools/llvm-isel-fuzzer/llvm-isel-fuzzer.cpp: In function ‘int LLVMFuzzerInitialize(int*, char***)’:
llvm-project/llvm/tools/llvm-isel-fuzzer/llvm-isel-fuzzer.cpp:141:43: error: ISO C++ forbids zero-size array ‘argv’ [-Werror=pedantic]
  141 |   ExitOnError ExitOnErr(std::string(*argv[0]) + ": error:");
      |

Author: jsji

llvm/tools/llvm-isel-fuzzer/llvm-isel-fuzzer.cpp

@@ -124,8 +124,10 @@ extern "C" LLVM_ATTRIBUTE_USED int LLVMFuzzerInitialize(int *argc,
   handleExecNameEncodedBEOpts(*argv[0]);
   parseFuzzerCLOpts(*argc, *argv);
 
+  std::string execName = *argv[0];
+
   if (TargetTriple.empty()) {
-    errs() << *argv[0] << ": -mtriple must be specified\n";
+    errs() << execName << ": -mtriple must be specified\n";
     exit(1);
   }
 
@@ -135,10 +137,10 @@ extern "C" LLVM_ATTRIBUTE_USED int LLVMFuzzerInitialize(int *argc,
   if (auto Level = CodeGenOpt::parseLevel(OptLevel)) {
     OLvl = *Level;
   } else {
-    errs() << argv[0] << ": invalid optimization level.\n";
+    errs() << execName << ": invalid optimization level.\n";
     return 1;
   }
-  ExitOnError ExitOnErr(std::string(*argv[0]) + ": error:");
+  ExitOnError ExitOnErr(std::string(execName) + ": error:");
   TM = ExitOnErr(codegen::createTargetMachineForTriple(
       Triple::normalize(TargetTriple), OLvl));
   assert(TM && "Could not allocate target machine!");

llvm/tools/llvm-opt-fuzzer/llvm-opt-fuzzer.cpp

@@ -193,27 +193,27 @@ extern "C" LLVM_ATTRIBUTE_USED int LLVMFuzzerInitialize(int *argc,
 
   // Create TargetMachine
   //
-
+  std::string execName = *argv[0];
   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)));
 
   // Check that pass pipeline is specified and correct
   //
 
   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);
   }