Run globs during earlier bootstrap phases

Instead of sometimes re-running minibp/the primary builder during the
next phase, run bpglob earlier to check dependencies.

We've run into issues where the environment is slightly different
between bootstrapping phase and the main build phase. It's also a
problem because our primary builder (Soong) exports information used by
another tool (Kati) that runs in between the bootstrapping phases and
the main phase. When Soong would run in the main phase, it could get out
of sync, and would require the build to be run again.

To do this, add a "subninja" include a build-globs.ninja file to each
build.ninja file. The first time, this will be an empty file, but we'll
always run minibp / the primary builder anyway. When the builder runs,
in addition to writing a dependency file, write out the
build-globs.ninja file with the rules to run bpglob.

Since bpglob may need to be run very early, before it would normally be
built, build it with microfactory.

Change-Id: I89fcd849a8729e892f163d40060ab90b5d4dfa5d

1 files changed, 14 insertions, 0 deletions

diff --git a/context.go b/context.go
index 919377c..69f26f6 100644
--- a/context.go
+++ b/context.go
@@ -102,6 +102,8 @@ type Context struct {
 	requiredNinjaMinor int          // For the ninja_required_version variable
 	requiredNinjaMicro int          // For the ninja_required_version variable
 
+	subninjas []string
+
 	// set lazily by sortedModuleGroups
 	cachedSortedModuleGroups []*moduleGroup
 
@@ -2939,6 +2941,11 @@ func (c *Context) WriteBuildFile(w io.Writer) error {
 		return err
 	}
 
+	err = c.writeSubninjas(nw)
+	if err != nil {
+		return err
+	}
+
 	// TODO: Group the globals by package.
 
 	err = c.writeGlobalVariables(nw)
@@ -3048,6 +3055,13 @@ func (c *Context) writeNinjaRequiredVersion(nw *ninjaWriter) error {
 	return nw.BlankLine()
 }
 
+func (c *Context) writeSubninjas(nw *ninjaWriter) error {
+	for _, subninja := range c.subninjas {
+		nw.Subninja(subninja)
+	}
+	return nw.BlankLine()
+}
+
 func (c *Context) writeBuildDir(nw *ninjaWriter) error {
 	if c.ninjaBuildDir != nil {
 		err := nw.Assign("builddir", c.ninjaBuildDir.Value(c.pkgNames))