Implement optimize(size) and optimize(speed) attributes

src/librustc/dep_graph/dep_node.rs

@@ -642,6 +642,7 @@ define_dep_nodes!( <'tcx>
     [eval_always] CollectAndPartitionMonoItems,
     [] IsCodegenedItem(DefId),
     [] CodegenUnit(InternedString),
+    [] BackendOptimizationLevel(CrateNum),
     [] CompileCodegenUnit(InternedString),
     [input] OutputFilenames,
     [] NormalizeProjectionTy(CanonicalProjectionGoal<'tcx>),

src/librustc/hir/mod.rs

@@ -21,7 +21,7 @@ use syntax::source_map::Spanned;
 use rustc_target::spec::abi::Abi;
 use syntax::ast::{self, CrateSugar, Ident, Name, NodeId, DUMMY_NODE_ID, AsmDialect};
 use syntax::ast::{Attribute, Label, Lit, StrStyle, FloatTy, IntTy, UintTy};
-use syntax::attr::InlineAttr;
+use syntax::attr::{InlineAttr, OptimizeAttr};
 use syntax::ext::hygiene::SyntaxContext;
 use syntax::ptr::P;
 use syntax::symbol::{Symbol, keywords};
@@ -2416,6 +2416,8 @@ pub struct CodegenFnAttrs {
     pub flags: CodegenFnAttrFlags,
     /// Parsed representation of the `#[inline]` attribute
     pub inline: InlineAttr,
+    /// Parsed representation of the `#[optimize]` attribute
+    pub optimize: OptimizeAttr,
     /// The `#[export_name = "..."]` attribute, indicating a custom symbol a
     /// function should be exported under
     pub export_name: Option<Symbol>,
@@ -2476,6 +2478,7 @@ impl CodegenFnAttrs {
         CodegenFnAttrs {
             flags: CodegenFnAttrFlags::empty(),
             inline: InlineAttr::None,
+            optimize: OptimizeAttr::None,
             export_name: None,
             link_name: None,
             target_features: vec![],

src/librustc/ich/impls_hir.rs

@@ -1159,6 +1159,7 @@ impl<'a> ToStableHashKey<StableHashingContext<'a>> for hir::TraitCandidate {
 impl_stable_hash_for!(struct hir::CodegenFnAttrs {
     flags,
     inline,
+    optimize,
     export_name,
     link_name,
     target_features,
@@ -1183,6 +1184,14 @@ impl<'hir> HashStable<StableHashingContext<'hir>> for attr::InlineAttr {
     }
 }
 
+impl<'hir> HashStable<StableHashingContext<'hir>> for attr::OptimizeAttr {
+    fn hash_stable<W: StableHasherResult>(&self,
+                                          hcx: &mut StableHashingContext<'hir>,
+                                          hasher: &mut StableHasher<W>) {
+        mem::discriminant(self).hash_stable(hcx, hasher);
+    }
+}
+
 impl_stable_hash_for!(struct hir::Freevar {
     def,
     span

src/librustc/session/config.rs

@@ -58,6 +58,8 @@ pub enum OptLevel {
     SizeMin,    // -Oz
 }
 
+impl_stable_hash_via_hash!(OptLevel);
+
 /// This is what the `LtoCli` values get mapped to after resolving defaults and
 /// and taking other command line options into account.
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]

src/librustc/ty/query/config.rs

@@ -967,6 +967,12 @@ impl<'tcx> QueryDescription<'tcx> for queries::dllimport_foreign_items<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription<'tcx> for queries::backend_optimization_level<'tcx> {
+    fn describe(_tcx: TyCtxt<'_, '_, '_>, _: CrateNum) -> Cow<'static, str> {
+        "optimization level used by backend".into()
+    }
+}
+
 macro_rules! impl_disk_cacheable_query(
     ($query_name:ident, |$key:tt| $cond:expr) => {
         impl<'tcx> QueryDescription<'tcx> for queries::$query_name<'tcx> {

src/librustc/ty/query/mod.rs

@@ -22,7 +22,7 @@ use mir::mono::CodegenUnit;
 use mir;
 use mir::interpret::GlobalId;
 use session::{CompileResult, CrateDisambiguator};
-use session::config::{EntryFnType, OutputFilenames};
+use session::config::{EntryFnType, OutputFilenames, OptLevel};
 use traits::{self, Vtable};
 use traits::query::{
     CanonicalPredicateGoal, CanonicalProjectionGoal,
@@ -573,6 +573,7 @@ define_queries! { <'tcx>
             -> (Arc<DefIdSet>, Arc<Vec<Arc<CodegenUnit<'tcx>>>>),
         [] fn is_codegened_item: IsCodegenedItem(DefId) -> bool,
         [] fn codegen_unit: CodegenUnit(InternedString) -> Arc<CodegenUnit<'tcx>>,
+        [] fn backend_optimization_level: BackendOptimizationLevel(CrateNum) -> OptLevel,
     },
 
     Other {

src/librustc/ty/query/plumbing.rs

@@ -1410,6 +1410,9 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
         DepKind::UpstreamMonomorphizationsFor => {
             force!(upstream_monomorphizations_for, def_id!());
         }
+        DepKind::BackendOptimizationLevel => {
+            force!(backend_optimization_level, krate!());
+        }
     }
 
     true

src/librustc_codegen_llvm/attributes.rs

@@ -5,7 +5,7 @@ use std::ffi::CString;
 use rustc::hir::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::session::Session;
-use rustc::session::config::Sanitizer;
+use rustc::session::config::{Sanitizer, OptLevel};
 use rustc::ty::{self, TyCtxt, PolyFnSig};
 use rustc::ty::layout::HasTyCtxt;
 use rustc::ty::query::Providers;
@@ -20,7 +20,7 @@ use attributes;
 use llvm::{self, Attribute};
 use llvm::AttributePlace::Function;
 use llvm_util;
-pub use syntax::attr::{self, InlineAttr};
+pub use syntax::attr::{self, InlineAttr, OptimizeAttr};
 
 use context::CodegenCx;
 use value::Value;
@@ -57,13 +57,6 @@ fn unwind(val: &'ll Value, can_unwind: bool) {
     Attribute::NoUnwind.toggle_llfn(Function, val, !can_unwind);
 }
 
-/// Tell LLVM whether it should optimize function for size.
-#[inline]
-#[allow(dead_code)] // possibly useful function
-pub fn set_optimize_for_size(val: &'ll Value, optimize: bool) {
-    Attribute::OptimizeForSize.toggle_llfn(Function, val, optimize);
-}
-
 /// Tell LLVM if this function should be 'naked', i.e., skip the epilogue and prologue.
 #[inline]
 pub fn naked(val: &'ll Value, is_naked: bool) {
@@ -151,6 +144,28 @@ pub fn non_lazy_bind(sess: &Session, llfn: &'ll Value) {
     }
 }
 
+pub(crate) fn default_optimisation_attrs(sess: &Session, llfn: &'ll Value) {
+    match sess.opts.optimize {
+        OptLevel::Size => {
+            llvm::Attribute::MinSize.unapply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeNone.unapply_llfn(Function, llfn);
+        },
+        OptLevel::SizeMin => {
+            llvm::Attribute::MinSize.apply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeNone.unapply_llfn(Function, llfn);
+        }
+        OptLevel::No => {
+            llvm::Attribute::MinSize.unapply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeForSize.unapply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeNone.unapply_llfn(Function, llfn);
+        }
+        _ => {}
+    }
+}
+
+
 /// Composite function which sets LLVM attributes for function depending on its AST (`#[attribute]`)
 /// attributes.
 pub fn from_fn_attrs(
@@ -162,6 +177,22 @@ pub fn from_fn_attrs(
     let codegen_fn_attrs = id.map(|id| cx.tcx.codegen_fn_attrs(id))
         .unwrap_or_else(|| CodegenFnAttrs::new());
 
+    match codegen_fn_attrs.optimize {
+        OptimizeAttr::None => {
+            default_optimisation_attrs(cx.tcx.sess, llfn);
+        }
+        OptimizeAttr::Speed => {
+            llvm::Attribute::MinSize.unapply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeForSize.unapply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeNone.unapply_llfn(Function, llfn);
+        }
+        OptimizeAttr::Size => {
+            llvm::Attribute::MinSize.apply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeNone.unapply_llfn(Function, llfn);
+        }
+    }
+
     inline(cx, llfn, codegen_fn_attrs.inline);
 
     // The `uwtable` attribute according to LLVM is:

src/librustc_codegen_llvm/back/lto.rs

@@ -3,7 +3,7 @@ use rustc_codegen_ssa::back::symbol_export;
 use rustc_codegen_ssa::back::write::{ModuleConfig, CodegenContext, pre_lto_bitcode_filename};
 use rustc_codegen_ssa::back::lto::{SerializedModule, LtoModuleCodegen, ThinShared, ThinModule};
 use rustc_codegen_ssa::traits::*;
-use back::write::{self, DiagnosticHandlers, with_llvm_pmb, save_temp_bitcode, get_llvm_opt_level};
+use back::write::{self, DiagnosticHandlers, with_llvm_pmb, save_temp_bitcode, to_llvm_opt_settings};
 use errors::{FatalError, Handler};
 use llvm::archive_ro::ArchiveRO;
 use llvm::{self, True, False};
@@ -532,7 +532,7 @@ pub(crate) fn run_pass_manager(cgcx: &CodegenContext<LlvmCodegenBackend>,
         // Note that in general this shouldn't matter too much as you typically
         // only turn on ThinLTO when you're compiling with optimizations
         // otherwise.
-        let opt_level = config.opt_level.map(get_llvm_opt_level)
+        let opt_level = config.opt_level.map(|x| to_llvm_opt_settings(x).0)
             .unwrap_or(llvm::CodeGenOptLevel::None);
         let opt_level = match opt_level {
             llvm::CodeGenOptLevel::None => llvm::CodeGenOptLevel::Less,

src/librustc_codegen_llvm/back/write.rs

@@ -5,8 +5,10 @@ use rustc_codegen_ssa::back::write::{CodegenContext, ModuleConfig, run_assembler
 use rustc_codegen_ssa::traits::*;
 use base;
 use consts;
+use rustc::hir::def_id::LOCAL_CRATE;
 use rustc::session::config::{self, OutputType, Passes, Lto};
 use rustc::session::Session;
+use rustc::ty::TyCtxt;
 use time_graph::Timeline;
 use llvm::{self, DiagnosticInfo, PassManager, SMDiagnostic};
 use llvm_util;
@@ -81,42 +83,46 @@ pub fn write_output_file(
     }
 }
 
-pub(crate) fn get_llvm_opt_level(optimize: config::OptLevel) -> llvm::CodeGenOptLevel {
-    match optimize {
-      config::OptLevel::No => llvm::CodeGenOptLevel::None,
-      config::OptLevel::Less => llvm::CodeGenOptLevel::Less,
-      config::OptLevel::Default => llvm::CodeGenOptLevel::Default,
-      config::OptLevel::Aggressive => llvm::CodeGenOptLevel::Aggressive,
-      _ => llvm::CodeGenOptLevel::Default,
-    }
-}
-
-pub(crate) fn get_llvm_opt_size(optimize: config::OptLevel) -> llvm::CodeGenOptSize {
-    match optimize {
-      config::OptLevel::Size => llvm::CodeGenOptSizeDefault,
-      config::OptLevel::SizeMin => llvm::CodeGenOptSizeAggressive,
-      _ => llvm::CodeGenOptSizeNone,
-    }
+pub fn create_target_machine(
+    tcx: TyCtxt,
+    find_features: bool,
+) -> &'static mut llvm::TargetMachine {
+    target_machine_factory(tcx.sess, tcx.backend_optimization_level(LOCAL_CRATE), find_features)()
+        .unwrap_or_else(|err| llvm_err(tcx.sess.diagnostic(), &err).raise() )
 }
 
-pub fn create_target_machine(
+pub fn create_informational_target_machine(
     sess: &Session,
     find_features: bool,
 ) -> &'static mut llvm::TargetMachine {
-    target_machine_factory(sess, find_features)().unwrap_or_else(|err| {
+    target_machine_factory(sess, config::OptLevel::No, find_features)().unwrap_or_else(|err| {
         llvm_err(sess.diagnostic(), &err).raise()
     })
 }
 
+
+pub fn to_llvm_opt_settings(cfg: config::OptLevel) -> (llvm::CodeGenOptLevel, llvm::CodeGenOptSize)
+{
+    use self::config::OptLevel::*;
+    match cfg {
+        No => (llvm::CodeGenOptLevel::None, llvm::CodeGenOptSizeNone),
+        Less => (llvm::CodeGenOptLevel::Less, llvm::CodeGenOptSizeNone),
+        Default => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeNone),
+        Aggressive => (llvm::CodeGenOptLevel::Aggressive, llvm::CodeGenOptSizeNone),
+        Size => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeDefault),
+        SizeMin => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeAggressive),
+    }
+}
+
 // If find_features is true this won't access `sess.crate_types` by assuming
 // that `is_pie_binary` is false. When we discover LLVM target features
 // `sess.crate_types` is uninitialized so we cannot access it.
-pub fn target_machine_factory(sess: &Session, find_features: bool)
+pub fn target_machine_factory(sess: &Session, optlvl: config::OptLevel, find_features: bool)
     -> Arc<dyn Fn() -> Result<&'static mut llvm::TargetMachine, String> + Send + Sync>
 {
     let reloc_model = get_reloc_model(sess);
 
-    let opt_level = get_llvm_opt_level(sess.opts.optimize);
+    let (opt_level, _) = to_llvm_opt_settings(optlvl);
     let use_softfp = sess.opts.cg.soft_float;
 
     let ffunction_sections = sess.target.target.options.function_sections;
@@ -357,7 +363,7 @@ pub(crate) unsafe fn optimize(cgcx: &CodegenContext<LlvmCodegenBackend>,
             if !config.no_prepopulate_passes {
                 llvm::LLVMRustAddAnalysisPasses(tm, fpm, llmod);
                 llvm::LLVMRustAddAnalysisPasses(tm, mpm, llmod);
-                let opt_level = config.opt_level.map(get_llvm_opt_level)
+                let opt_level = config.opt_level.map(|x| to_llvm_opt_settings(x).0)
                     .unwrap_or(llvm::CodeGenOptLevel::None);
                 let prepare_for_thin_lto = cgcx.lto == Lto::Thin || cgcx.lto == Lto::ThinLocal ||
                     (cgcx.lto != Lto::Fat && cgcx.opts.debugging_opts.cross_lang_lto.enabled());
@@ -689,7 +695,8 @@ pub unsafe fn with_llvm_pmb(llmod: &llvm::Module,
     // reasonable defaults and prepare it to actually populate the pass
     // manager.
     let builder = llvm::LLVMPassManagerBuilderCreate();
-    let opt_size = config.opt_size.map(get_llvm_opt_size).unwrap_or(llvm::CodeGenOptSizeNone);
+    let opt_size = config.opt_size.map(|x| to_llvm_opt_settings(x).1)
+        .unwrap_or(llvm::CodeGenOptSizeNone);
     let inline_threshold = config.inline_threshold;
 
     let pgo_gen_path = config.pgo_gen.as_ref().map(|s| {

src/librustc_codegen_llvm/base.rs

@@ -136,7 +136,7 @@ pub fn iter_globals(llmod: &'ll llvm::Module) -> ValueIter<'ll> {
     }
 }
 
-pub fn compile_codegen_unit<'ll, 'tcx>(tcx: TyCtxt<'ll, 'tcx, 'tcx>,
+pub fn compile_codegen_unit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                   cgu_name: InternedString)
                                   -> Stats {
     let start_time = Instant::now();
@@ -164,7 +164,7 @@ pub fn compile_codegen_unit<'ll, 'tcx>(tcx: TyCtxt<'ll, 'tcx, 'tcx>,
         let backend = LlvmCodegenBackend(());
         let cgu = tcx.codegen_unit(cgu_name);
         // Instantiate monomorphizations without filling out definitions yet...
-        let llvm_module = backend.new_metadata(tcx.sess, &cgu_name.as_str());
+        let llvm_module = backend.new_metadata(tcx, &cgu_name.as_str());
         let stats = {
             let cx = CodegenCx::new(tcx, cgu, &llvm_module);
             let mono_items = cx.codegen_unit

src/librustc_codegen_llvm/context.rs

@@ -144,16 +144,17 @@ pub fn is_pie_binary(sess: &Session) -> bool {
 }
 
 pub unsafe fn create_module(
-    sess: &Session,
+    tcx: TyCtxt,
     llcx: &'ll llvm::Context,
     mod_name: &str,
 ) -> &'ll llvm::Module {
+    let sess = tcx.sess;
     let mod_name = SmallCStr::new(mod_name);
     let llmod = llvm::LLVMModuleCreateWithNameInContext(mod_name.as_ptr(), llcx);
 
     // Ensure the data-layout values hardcoded remain the defaults.
     if sess.target.target.options.is_builtin {
-        let tm = ::back::write::create_target_machine(sess, false);
+        let tm = ::back::write::create_target_machine(tcx, false);
         llvm::LLVMRustSetDataLayoutFromTargetMachine(llmod, tm);
         llvm::LLVMRustDisposeTargetMachine(tm);
 

src/librustc_codegen_llvm/declare.rs

@@ -65,19 +65,8 @@ fn declare_raw_fn(
         }
     }
 
-    match cx.tcx.sess.opts.cg.opt_level.as_ref().map(String::as_ref) {
-        Some("s") => {
-            llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
-        },
-        Some("z") => {
-            llvm::Attribute::MinSize.apply_llfn(Function, llfn);
-            llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
-        },
-        _ => {},
-    }
-
+    attributes::default_optimisation_attrs(cx.tcx.sess, llfn);
     attributes::non_lazy_bind(cx.sess(), llfn);
-
     llfn
 }