[clang] [clang] Fix use of dangling ptr in CommandLineTest (PR #119798)

[via cfe-commits]

https://github.com/macurtis-amd created https://github.com/llvm/llvm-project/pull/119798

If 'GeneratedArgsStorage' ever grows, contained strings may get copied and data pointers stored in 'GeneratedArgs' may become invalid, pointing to deallocated memory.

>From 52bc1d826b7df0c9fbeb7d991e899909e260f86b Mon Sep 17 00:00:00 2001
From: Matthew Curtis <macurtis at amd.com>
Date: Thu, 12 Dec 2024 18:56:29 -0600
Subject: [PATCH] [clang] Fix use of dangling ptr in CommandLineTest

If 'GeneratedArgsStorage' ever grows, contained strings may get copied and data
pointers stored in 'GeneratedArgs' may become invalid, pointing to deallocated
memory.
---
 clang/unittests/Frontend/CompilerInvocationTest.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/clang/unittests/Frontend/CompilerInvocationTest.cpp b/clang/unittests/Frontend/CompilerInvocationTest.cpp
index 4ff6824f1e21e3..94ab9fe8451e0a 100644
--- a/clang/unittests/Frontend/CompilerInvocationTest.cpp
+++ b/clang/unittests/Frontend/CompilerInvocationTest.cpp
@@ -31,17 +31,19 @@ class CommandLineTest : public ::testing::Test {
 public:
   IntrusiveRefCntPtr<DiagnosticsEngine> Diags;
   SmallVector<const char *, 32> GeneratedArgs;
-  SmallVector<std::string, 32> GeneratedArgsStorage;
+  BumpPtrAllocator Alloc;
+  StringSaver StringPool;
   CompilerInvocation Invocation;
 
   const char *operator()(const Twine &Arg) {
-    return GeneratedArgsStorage.emplace_back(Arg.str()).c_str();
+    return StringPool.save(Arg).data();
   }
 
   CommandLineTest()
       : Diags(CompilerInstance::createDiagnostics(
             *llvm::vfs::getRealFileSystem(), new DiagnosticOptions(),
-            new TextDiagnosticBuffer())) {}
+            new TextDiagnosticBuffer())),
+        StringPool(Alloc) {}
 };
 
 template <typename M>