[clang] [clang][DebugInfo] Attach `DISubprogram` to additional call variants (PR #166202)

[J. Ryan Stinnett via cfe-commits]

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@@ -6277,6 +6277,21 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
     pushDestroy(QualType::DK_nontrivial_c_struct, Ret.getAggregateAddress(),
                 RetTy);
 
+  if (CalleeDecl) {
+    // Generate function declaration DISuprogram in order to be used
+    // in debug info about call sites.
+    if (CGDebugInfo *DI = getDebugInfo()) {
+      CodeGenFunction CalleeCGF(CGM);
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jryans wrote:

Here's a new round of compile time [results](http://llvm-compile-time-tracker.com/compare.php?from=34a34888152388c91dd66c10eefd600b3200e779&to=15cfbe5ae7d4ff4a48a648a9f5fa54404d5b3846&stat=instructions%3Au) after lifting up the call site emission conditions check.

We're now doing _less_ work on average for many O0 debug runs since we're checking whether to emit earlier than the previous version did. The O3 debug run continues to show a slight increase above baseline, but that's expected since there's a bit more call site emission work happening in optimised debug runs.

Please take a look and let me know if this round looks good to you as well.

https://github.com/llvm/llvm-project/pull/166202