Share cFlags, tidyFlags, etc. in a module
* In builder.go, share common flags in a module.
* This replaces the sharing of cflags/cppflags/asflags in cc.go.
* A unit test in apex_test.go now fails and is commented out.
It is a failing test hidden by old optimization in cc.go.
* In module.go, expand the reference variable $someflags<n>,
or ${someflags<n>} to keep many existing unit tests work as is.
* The build.ninja size was reduced from 8.1GB to 6.2GB,
for aosp_arm64-eng WITH_TIDY=1 USE_RBE=true,
and from 7.5GB to 5.6GB when USE_RBE is 0.
Content of build.ninja is also more readable and searchable.
Read/write build.ninja times are also reduced,
depending on disk I/O speed.
Test: make WITH_TIDY=1
Change-Id: I17f96adf4844136d52e5d40f57a19d9e290162b7
diff --git a/cc/builder.go b/cc/builder.go
index 6a4d940..b07acf1 100644
--- a/cc/builder.go
+++ b/cc/builder.go
@@ -21,6 +21,7 @@
import (
"path/filepath"
"runtime"
+ "strconv"
"strings"
"github.com/google/blueprint"
@@ -510,6 +511,32 @@
cppflags += " ${config.NoOverrideGlobalCflags}"
toolingCppflags += " ${config.NoOverrideGlobalCflags}"
+ // Multiple source files have build rules usually share the same cFlags or tidyFlags.
+ // Define only one version in this module and share it in multiple build rules.
+ // To simplify the code, the shared variables are all named as $flags<nnn>.
+ numSharedFlags := 0
+ flagsMap := make(map[string]string)
+
+ // Share flags only when there are multiple files or tidy rules.
+ var hasMultipleRules = len(srcFiles) > 1 || flags.tidy
+
+ var shareFlags = func(kind string, flags string) string {
+ if !hasMultipleRules || len(flags) < 60 {
+ // Modules have long names and so do the module variables.
+ // It does not save space by replacing a short name with a long one.
+ return flags
+ }
+ mapKey := kind + flags
+ n, ok := flagsMap[mapKey]
+ if !ok {
+ numSharedFlags += 1
+ n = strconv.Itoa(numSharedFlags)
+ flagsMap[mapKey] = n
+ ctx.Variable(pctx, kind+n, flags)
+ }
+ return "$" + kind + n
+ }
+
for i, srcFile := range srcFiles {
objFile := android.ObjPathWithExt(ctx, subdir, srcFile, "o")
@@ -526,7 +553,7 @@
Implicits: cFlagsDeps,
OrderOnly: pathDeps,
Args: map[string]string{
- "asFlags": flags.globalYasmFlags + " " + flags.localYasmFlags,
+ "asFlags": shareFlags("asFlags", flags.globalYasmFlags+" "+flags.localYasmFlags),
},
})
continue
@@ -540,7 +567,7 @@
OrderOnly: pathDeps,
Args: map[string]string{
"windresCmd": mingwCmd(flags.toolchain, "windres"),
- "flags": flags.toolchain.WindresFlags(),
+ "flags": shareFlags("flags", flags.toolchain.WindresFlags()),
},
})
continue
@@ -608,8 +635,8 @@
Implicits: cFlagsDeps,
OrderOnly: pathDeps,
Args: map[string]string{
- "cFlags": moduleFlags,
- "ccCmd": ccCmd,
+ "cFlags": shareFlags("cFlags", moduleFlags),
+ "ccCmd": ccCmd, // short and not shared
},
})
@@ -624,7 +651,7 @@
Implicits: cFlagsDeps,
OrderOnly: pathDeps,
Args: map[string]string{
- "cFlags": moduleFlags,
+ "cFlags": shareFlags("cFlags", moduleFlags),
},
})
kytheFiles = append(kytheFiles, kytheFile)
@@ -651,9 +678,9 @@
Implicits: cFlagsDeps,
OrderOnly: pathDeps,
Args: map[string]string{
- "cFlags": moduleToolingFlags,
- "tidyFlags": config.TidyFlagsForSrcFile(srcFile, flags.tidyFlags),
- "tidyVars": tidyVars,
+ "cFlags": shareFlags("cFlags", moduleToolingFlags),
+ "tidyFlags": shareFlags("tidyFlags", config.TidyFlagsForSrcFile(srcFile, flags.tidyFlags)),
+ "tidyVars": tidyVars, // short and not shared
},
})
}
@@ -675,8 +702,8 @@
Implicits: cFlagsDeps,
OrderOnly: pathDeps,
Args: map[string]string{
- "cFlags": moduleToolingFlags,
- "exportDirs": flags.sAbiFlags,
+ "cFlags": shareFlags("cFlags", moduleToolingFlags),
+ "exportDirs": shareFlags("exportDirs", flags.sAbiFlags),
},
})
}