all: use compiler-rt for builtins

buildcache.go

@@ -0,0 +1,108 @@
+package main
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+// Get the cache directory, usually ~/.cache/tinygo
+func cacheDir() string {
+	home := getHomeDir()
+	dir := filepath.Join(home, ".cache", "tinygo")
+	return dir
+}
+
+// Return the newest timestamp of all the file paths passed in. Used to check
+// for stale caches.
+func cacheTimestamp(paths []string) (time.Time, error) {
+	var timestamp time.Time
+	for _, path := range paths {
+		st, err := os.Stat(path)
+		if err != nil {
+			return time.Time{}, err
+		}
+		if timestamp.IsZero() {
+			timestamp = st.ModTime()
+		} else if timestamp.Before(st.ModTime()) {
+			timestamp = st.ModTime()
+		}
+	}
+	return timestamp, nil
+}
+
+// Try to load a given file from the cache. Return "", nil if no cached file can
+// be found (or the file is stale), return the absolute path if there is a cache
+// and return an error on I/O errors.
+//
+// TODO: the configKey is currently ignored. It is supposed to be used as extra
+// data for the cache key, like the compiler version and arguments.
+func cacheLoad(name, configKey string, sourceFiles []string) (string, error) {
+	dir := cacheDir()
+	cachepath := filepath.Join(dir, name)
+	cacheStat, err := os.Stat(cachepath)
+	if os.IsNotExist(err) {
+		return "", nil // does not exist
+	} else if err != nil {
+		return "", err // cannot stat cache file
+	}
+
+	sourceTimestamp, err := cacheTimestamp(sourceFiles)
+	if err != nil {
+		return "", err // cannot stat source files
+	}
+
+	if cacheStat.ModTime().After(sourceTimestamp) {
+		return cachepath, nil
+	} else {
+		os.Remove(cachepath)
+		// stale cache
+		return "", nil
+	}
+}
+
+// Store the file located at tmppath in the cache with the given name. The
+// tmppath may or may not be gone afterwards.
+//
+// Note: the configKey is ignored, see cacheLoad.
+func cacheStore(tmppath, name, configKey string, sourceFiles []string) (string, error) {
+	// get the last modified time
+	if len(sourceFiles) == 0 {
+		panic("cache: no source files")
+	}
+
+	// TODO: check the config key
+
+	dir := cacheDir()
+	err := os.MkdirAll(dir, 0777)
+	if err != nil {
+		return "", err
+	}
+	cachepath := filepath.Join(dir, name)
+	err = os.Rename(tmppath, cachepath)
+	if err != nil {
+		inf, err := os.Open(tmppath)
+		if err != nil {
+			return "", err
+		}
+		defer inf.Close()
+		outf, err := os.Create(cachepath + ".tmp")
+		if err != nil {
+			return "", err
+		}
+
+		_, err = io.Copy(outf, inf)
+		if err != nil {
+			return "", err
+		}
+
+		err = os.Rename(cachepath+".tmp", cachepath)
+		if err != nil {
+			return "", err
+		}
+
+		return cachepath, outf.Close()
+	}
+	return cachepath, nil
+}