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

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-x86_64-debian` running on `lldb-x86_64-debian` while building `llvm` at step 6 "test".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/162/builds/10296

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test) failure: build (failure)
...
PASS: lldb-api :: lang/cpp/const_static_integral_member/TestConstStaticIntegralMember.py (53 of 2703)
PASS: lldb-api :: tools/lldb-dap/disconnect/TestDAP_disconnect.py (54 of 2703)
PASS: lldb-api :: python_api/frame/TestFrames.py (55 of 2703)
PASS: lldb-api :: functionalities/thread/num_threads/TestNumThreads.py (56 of 2703)
PASS: lldb-api :: functionalities/stop-on-sharedlibrary-load/TestStopOnSharedlibraryEvents.py (57 of 2703)
PASS: lldb-api :: commands/process/launch/TestProcessLaunch.py (58 of 2703)
PASS: lldb-api :: python_api/watchpoint/watchlocation/TestSetWatchlocation.py (59 of 2703)
PASS: lldb-api :: functionalities/step-avoids-no-debug/TestStepNoDebug.py (60 of 2703)
PASS: lldb-api :: tools/lldb-server/TestGdbRemoteExitCode.py (61 of 2703)
PASS: lldb-api :: python_api/find_in_memory/TestFindRangesInMemory.py (62 of 2703)
FAIL: lldb-api :: source-manager/TestSourceManager.py (63 of 2703)
******************** TEST 'lldb-api :: source-manager/TestSourceManager.py' FAILED ********************
Script:
--
/usr/bin/python3 /home/worker/2.0.1/lldb-x86_64-debian/llvm-project/lldb/test/API/dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=/home/worker/2.0.1/lldb-x86_64-debian/build/./lib --env LLVM_INCLUDE_DIR=/home/worker/2.0.1/lldb-x86_64-debian/build/include --env LLVM_TOOLS_DIR=/home/worker/2.0.1/lldb-x86_64-debian/build/./bin --arch x86_64 --build-dir /home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex --lldb-module-cache-dir /home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex/module-cache-lldb/lldb-api --clang-module-cache-dir /home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex/module-cache-clang/lldb-api --executable /home/worker/2.0.1/lldb-x86_64-debian/build/./bin/lldb --compiler /home/worker/2.0.1/lldb-x86_64-debian/build/./bin/clang --dsymutil /home/worker/2.0.1/lldb-x86_64-debian/build/./bin/dsymutil --make /usr/bin/make --llvm-tools-dir /home/worker/2.0.1/lldb-x86_64-debian/build/./bin --lldb-obj-root /home/worker/2.0.1/lldb-x86_64-debian/build/tools/lldb --lldb-libs-dir /home/worker/2.0.1/lldb-x86_64-debian/build/./lib -t /home/worker/2.0.1/lldb-x86_64-debian/llvm-project/lldb/test/API/source-manager -p TestSourceManager.py
--
Exit Code: 1

Command Output (stdout):
--
lldb version 20.0.0git (https://github.com/llvm/llvm-project.git revision bf483ddb42065405e345393e022dc72357ec5a3a)
  clang revision bf483ddb42065405e345393e022dc72357ec5a3a
  llvm revision bf483ddb42065405e345393e022dc72357ec5a3a
Skipping the following test categories: ['libc++', 'dsym', 'gmodules', 'debugserver', 'objc']
original content: #include <stdio.h>

int main(int argc, char const *argv[]) {
    printf("Hello world.\n"); // Set break point at this line.
    return 0;
}

new content: #include <stdio.h>

int main(int argc, char const *argv[]) {
    printf("Hello lldb.\n"); // Set break point at this line.
    return 0;
}

os.path.getmtime() after writing new content: 1731424476.6795385
original content: #include <stdio.h>

int main(int argc, char const *argv[]) {
    printf("Hello world.\n"); // Set break point at this line.
    return 0;
}

new content: #include <stdio.h>

int main(int argc, char const *argv[]) {

```

</details>

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