Run regen commands sequentially
When I remove --ignore-dirty=$(OUT_DIR)/% from an Android build, it
turns out that we have $(shell) commands that have side effects and
cannot be reordered in relationship to one another. The trivial case is
a sequence of 'rm', 'write', 'write'..., 'cmp'. The 'rm' and 'write'
commands can be collapsed into a single $(file) function call, but it
still needs to be ordered for the 'cmp' function to work properly.
I've been making changes to prevent this from slowing down regen too
much, but it's still a 2-3x slowdown overall (0.3s -> 0.8s for
aosp_arm64-eng on aosp master).
diff --git a/regen.cc b/regen.cc
index f5ed50a..f7db27d 100644
--- a/regen.cc
+++ b/regen.cc
@@ -375,8 +375,8 @@
}
});
- for (ShellResult* sr : commands_) {
- tp->Submit([this, sr]() {
+ tp->Submit([this]() {
+ for (ShellResult* sr : commands_) {
string err;
if (CheckShellResult(sr, &err)) {
unique_lock<mutex> lock(mu_);
@@ -385,8 +385,8 @@
msg_ = err;
}
}
- });
- }
+ }
+ });
tp->Wait();
if (needs_regen_) {