Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/third_party/libwebrtc/build/docs/debugging_slow_builds.md b/third_party/libwebrtc/build/docs/debugging_slow_builds.md
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+# Debugging slow builds
+
+Some tips for debugging slow build times:
+* Use [ninjatracing](https://github.com/nico/ninjatracing) and chrome:tracing to
+  view a timeline of the most recent build.
+  * Many bots output a build trace (look for a `"ninja_log"` link).
+* Use `gn gen --tracelog trace.json` to create a similar trace for `gn gen`.
+* Depot Tool's `autoninja` has logic for summarizing slow steps. Enable it via:
+  * `NINJA_SUMMARIZE_BUILD=1 autoninja -C out/Debug my_target`
+* Many Android templates make use of
+  [`md5_check.py`](https://cs.chromium.org/chromium/src/build/android/gyp/util/md5_check.py)
+  to optimize incremental builds.
+  * Set `PRINT_BUILD_EXPLANATIONS=1` to have these commands log which inputs
+    changed.
+* If you suspect files are being rebuilt unnecessarily during incremental
+  builds:
+  * Use `ninja -n -d explain` to figure out why ninja thinks a target is dirty.
+  * Ensure actions are taking advantage of ninja's `restat=1` feature by not
+    updating timestamps on outputs when their content does not change.