[clang] [llvm] [Clang] Show inlining hints for __attribute__((warning/error)) (PR #174892)

[Nick Desaulniers via cfe-commits]

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@@ -2253,6 +2253,14 @@ bool CompilerInvocation::ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args,
       Opts.getDebugInfo() == llvm::codegenoptions::NoDebugInfo)
     Opts.setDebugInfo(llvm::codegenoptions::LocTrackingOnly);
 
+  // Debug mode for inlining chain diagnostics requires at least
+  // -gline-directives-only to track inlining locations via DILocation.
+  if (Opts.getInliningChain() == CodeGenOptions::Inlining_Debug &&
+      Opts.getDebugInfo() < llvm::codegenoptions::DebugDirectivesOnly) {
+    Diags.Report(diag::warn_fe_inlining_debug_requires_g);
+    Opts.setInliningChain(CodeGenOptions::Inlining_Heuristic);
+  }
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nickdesaulniers wrote:

Maybe it would be better to emit a Note diagnostic on the -Wwarning diagnostics if `FD->getStorageClass() == SC_Static` that enabling `-gline-directives-only` (or higher level debug flags) can provide additional info?

https://github.com/llvm/llvm-project/pull/174892