[llvm] [TableGen] Detect invalid -D arguments and fail. (PR #102813)

[Sergei Barannikov via llvm-commits]

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@@ -54,9 +74,17 @@ TGLexer::TGLexer(SourceMgr &SM, ArrayRef<std::string> Macros) : SrcMgr(SM) {
   PrepIncludeStack.push_back(
       std::make_unique<std::vector<PreprocessorControlDesc>>());
 
-  // Put all macros defined in the command line into the DefinedMacros set.
-  for (const std::string &MacroName : Macros)
+  // Add all macros defined on the command line to the DefinedMacros set.
+  // Check invalid macro names and print fatal error if we find one.
+  for (const std::string &MacroName : Macros) {
+    const char *Begin = MacroName.c_str();
+    const char *End = lexMacroName(Begin);
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s-barannikov wrote:

https://en.cppreference.com/w/cpp/string/basic_string/data
> The returned array is null-terminated, that is, data() and [c_str()](https://en.cppreference.com/w/cpp/string/basic_string/c_str) perform the same function.
> If [empty()](https://en.cppreference.com/w/cpp/string/basic_string/empty) returns true, the pointer points to a single null character.
> (since C++11)

https://github.com/llvm/llvm-project/pull/102813