Allow metadata to be not compressed

Author: brson

Makefile.in

@@ -107,6 +107,12 @@ else
   CFG_GCCISH_CFLAGS += -DRUST_NDEBUG
 endif
 
+ifndef CFG_ENABLE_COMPRESS_METADATA
+  # XXX: After snapshots extend this to all stages
+  RUSTFLAGS_STAGE1 += --no-compress-metadata
+  RUSTFLAGS_STAGE2 += --no-compress-metadata
+endif
+
 ifdef SAVE_TEMPS
   CFG_RUSTC_FLAGS += --save-temps
 endif

configure

@@ -381,7 +381,9 @@ opt mingw-cross 0 "cross-compile for win32 using mingw"
 opt clang 0 "prefer clang to gcc for building the runtime"
 opt ccache 0 "invoke gcc/clang via ccache to reuse object files between builds"
 opt local-rust 0 "use an installed rustc rather than downloading a snapshot"
-opt pax-flags 0 "apply PaX flags to rustc binaries (required for GRSecurity/PaX-patched kernels)"
+opt pax-flags 0 "apply PaX flags to rustc binaries (required for GRSecurity/PaX-patched
+ kernels)"
+opt compress-metadata 0 "compress crate metadata"
 valopt prefix "/usr/local" "set installation prefix"
 valopt local-rust-root "/usr/local" "set prefix for local rust binary"
 valopt llvm-root "" "set LLVM root"

src/librustc/driver/driver.rs

@@ -718,6 +718,8 @@ pub fn build_session_options(binary: @str,
     let android_cross_path = getopts::opt_maybe_str(
         matches, "android-cross-path");
 
+    let no_compress_metadata = opt_present(matches, "no-compress-metadata");
+
     let custom_passes = match getopts::opt_maybe_str(matches, "passes") {
         None => ~[],
         Some(s) => {
@@ -752,7 +754,8 @@ pub fn build_session_options(binary: @str,
         parse_only: parse_only,
         no_trans: no_trans,
         debugging_opts: debugging_opts,
-        android_cross_path: android_cross_path
+        android_cross_path: android_cross_path,
+        no_compress_metadata: no_compress_metadata
     };
     return sopts;
 }
@@ -870,6 +873,8 @@ pub fn optgroups() -> ~[getopts::groups::OptGroup] {
                           for details)", "FEATURE"),
   optopt("", "android-cross-path",
          "The path to the Android NDK", "PATH"),
+  optflag("", "no-compress-metadata",
+          "Do not compress crate metadata (make builds a little faster)"),
   optflagopt("W", "warn",
                         "Set lint warnings", "OPT"),
   optmulti("A", "allow",

src/librustc/driver/session.rs

@@ -166,6 +166,7 @@ pub struct options {
     no_trans: bool,
     debugging_opts: uint,
     android_cross_path: Option<~str>,
+    no_compress_metadata: bool
 }
 
 pub struct crate_metadata {
@@ -350,6 +351,7 @@ pub fn basic_options() -> @options {
         no_trans: false,
         debugging_opts: 0u,
         android_cross_path: None,
+        no_compress_metadata: false
     }
 }
 

src/librustc/metadata/encoder.rs

@@ -64,6 +64,7 @@ pub struct EncodeParams<'self> {
     cstore: @mut cstore::CStore,
     encode_inlined_item: encode_inlined_item<'self>,
     reachable: @mut HashSet<ast::NodeId>,
+    compress: bool
 }
 
 struct Stats {
@@ -1567,7 +1568,7 @@ pub static metadata_encoding_version : &'static [u8] =
       0x75, //'u' as u8,
       0x73, //'s' as u8,
       0x74, //'t' as u8,
-      0, 0, 0, 1 ];
+      0, 0, 0, 2 ];
 
 pub fn encode_metadata(parms: EncodeParams, crate: &Crate) -> ~[u8] {
     let wr = @io::BytesWriter::new();
@@ -1594,6 +1595,7 @@ pub fn encode_metadata(parms: EncodeParams, crate: &Crate) -> ~[u8] {
         encode_inlined_item,
         link_meta,
         reachable,
+        compress,
         _
     } = parms;
     let type_abbrevs = @mut HashMap::new();
@@ -1679,9 +1681,17 @@ pub fn encode_metadata(parms: EncodeParams, crate: &Crate) -> ~[u8] {
     wr.write(&[0u8, 0u8, 0u8, 0u8]);
 
     let writer_bytes: &mut ~[u8] = wr.bytes;
-
-    metadata_encoding_version.to_owned() +
-        flate::deflate_bytes(*writer_bytes)
+    let compression_flag = if compress { [1u8] } else { [0u8] };
+
+    if compress {
+        metadata_encoding_version.to_owned() +
+            compression_flag.to_owned() +
+            flate::deflate_bytes(*writer_bytes)
+    } else {
+        metadata_encoding_version.to_owned() +
+            compression_flag.to_owned() +
+            *writer_bytes
+    }
 }
 
 // Get the encoded string for a type

src/librustc/metadata/loader.rs

@@ -228,13 +228,26 @@ fn get_metadata_section(os: os,
                 }
                 if !version_ok { return None; }
 
-                let cvbuf1 = ptr::offset(cvbuf, vlen as int);
-                debug!("inflating %u bytes of compressed metadata",
-                       csz - vlen);
-                do vec::raw::buf_as_slice(cvbuf1, csz-vlen) |bytes| {
-                    let inflated = flate::inflate_bytes(bytes);
-                    found = Some(@(inflated));
+                assert!(csz >= vlen + 1);
+
+                let must_decompress = *ptr::offset(cvbuf, vlen as int) == 1;
+                let cvbuf1 = ptr::offset(cvbuf, vlen as int + 1);
+
+                do vec::raw::buf_as_slice(cvbuf1, csz-vlen-1) |bytes| {
+                    if must_decompress {
+                        debug!("inflating %u bytes of compressed metadata",
+                               csz - vlen);
+                        let inflated = flate::inflate_bytes(bytes);
+                        found = Some(@(inflated));
+                    } else {
+                        // Copy the byte vector as fast as possible
+                        let mut buf = vec::with_capacity(bytes.len());
+                        vec::raw::set_len(&mut buf, bytes.len());
+                        vec::raw::copy_memory(buf, bytes, bytes.len());
+                        found = Some(@buf)
+                    }
                 }
+
                 if found != None {
                     return found;
                 }

src/librustc/middle/trans/base.rs

@@ -2907,6 +2907,7 @@ pub fn crate_ctxt_to_encode_parms<'r>(cx: &'r CrateContext, ie: encoder::encode_
             cstore: cx.sess.cstore,
             encode_inlined_item: ie,
             reachable: cx.reachable,
+            compress: !cx.sess.opts.no_compress_metadata
         }
 }