[all-commits] [llvm/llvm-project] 76cb4c: [clang] Fix serialized diagnostics edge-cases

[Jan Svoboda via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 76cb4cd074a6816f3801fd4a2bd8854597748239
      https://github.com/llvm/llvm-project/commit/76cb4cd074a6816f3801fd4a2bd8854597748239
  Author: Jan Svoboda <jan_svoboda at apple.com>
  Date:   2022-01-26 (Wed, 26 Jan 2022)

  Changed paths:
    M clang/lib/Frontend/CompilerInstance.cpp
    A clang/test/Misc/serialized-diags-emit-header-module-misconfig.c
    A clang/test/Misc/serialized-diags-unknown-argument.c
    A clang/test/Misc/serialized-diags-unknown-target.c
    M clang/tools/driver/cc1_main.cpp

  Log Message:
  -----------
  [clang] Fix serialized diagnostics edge-cases

The Clang frontend sometimes fails on the following assertion when launched with `-serialize-diagnostic-file <x>`:

```
Assertion failed: (BlockScope.empty() && CurAbbrevs.empty() && "Block imbalance"), function ~BitstreamWriter, file BitstreamWriter.h, line 125.
```

This was first noticed when passing an unknown command-line argument to `-cc1`.

It turns out the `DiagnosticConsumer::finish()` function should be called as soon as processing of all source files ends, but there are some code paths where that doesn't happen:

1. when command line parsing fails in `cc1_main()`,
2. when `!Act.PrepareToExecute(*this)` or `!createTarget()` evaluate to `true` in `CompilerInstance::ExecuteAction` and the function returns early.

This patch ensures `finish()` is called in all those code paths.

Reviewed By: Bigcheese

Differential Revision: https://reviews.llvm.org/D118150