[PATCH] D110740: Do not emit prologue_end for line 0 locs if there is a non-zero loc present

[Adrian Prantl via Phabricator via llvm-commits]

aprantl added a comment.

Thanks, this LGTM after addressing all of @probinson s comments!



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Comment at: llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:2097
+        // save off line 0 .loc location and return that if no non-zero location
+        // is found
+        if (MI.getDebugLoc().getLine())
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Maybe we should also explain the rationale behind this:
```
// Scan forward to try to find a non-zero line number. The prologue_end marks the first breakpoint in the function after the frame setup, and a compiler-generated line 0 location is not a meaningful breakpoint. If none is found, return the first location after the frame setup.
```


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Comment at: llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:2100
+          return MI.getDebugLoc();
+        LineZeroLoc = MI.getDebugLoc();
+      }
----------------
This is also a problem with the original code, but findPrologueEndLoc should probably not scan past the first basic block. Your patch doesn't make this any worse though.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110740/new/

https://reviews.llvm.org/D110740