[llvm] [DWARF] Emit a worst-case prologue_end flag for pathological inputs (PR #107849)

[Michael Buch via llvm-commits]

Michael137 wrote:

Looks like this is breaking the `source-manager/TestSourceManager.py` LLDB test on macOS: https://green.lab.llvm.org/job/llvm.org/view/LLDB/job/as-lldb-cmake/15127/execution/node/97/log/
```
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FAIL: test_artificial_source_location (TestSourceManager.SourceManagerTestCase)
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Traceback (most recent call last):
  File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/source-manager/TestSourceManager.py", line 325, in test_artificial_source_location
    self.expect(
  File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 2475, in expect
    self.fail(log_msg)
AssertionError: Ran command:
"process status"

Got output:
Process 99092 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
    frame #0: 0x000000010402bf8c a.out`main at artificial_location.c:3
   1   	int foo() { return 42; }
   2   	
-> 3   	int main() {
   4   	#line 0
   5   	  return foo();
   6   	}

Expecting sub string: "stop reason = breakpoint" (was found)
Expecting sub string: "artificial_location.c:0" (was not found)
Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
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```

Could you please take a look?

https://github.com/llvm/llvm-project/pull/107849