Add a compilation pass timing facility.

Individual compilation passes call the corresponding timing::*()
function and hold on to their timing token while they run. This causes
nested per-pass timing information to be recorded in thread-local
storage.

The --time-passes command line option prints a pass timing report to
stdout.

lib/cretonne/src/verifier/cssa.rs

@@ -6,6 +6,7 @@ use ir::Function;
 use regalloc::liveness::Liveness;
 use regalloc::virtregs::VirtRegs;
 use std::cmp::Ordering;
+use timing;
 use verifier::Result;
 
 /// Verify conventional SSA form for `func`.
@@ -29,6 +30,7 @@ pub fn verify_cssa(
     liveness: &Liveness,
     virtregs: &VirtRegs,
 ) -> Result {
+    let _tt = timing::verify_cssa();
     let verifier = CssaVerifier {
         func,
         cfg,

lib/cretonne/src/verifier/flags.rs

@@ -8,6 +8,7 @@ use isa;
 use packed_option::PackedOption;
 use std::result;
 use verifier::{Result, Error};
+use timing;
 
 /// Verify that CPU flags are used correctly.
 ///
@@ -26,6 +27,7 @@ pub fn verify_flags(
     cfg: &ControlFlowGraph,
     isa: Option<&isa::TargetIsa>,
 ) -> Result {
+    let _tt = timing::verify_flags();
     let mut verifier = FlagsVerifier {
         func,
         cfg,

lib/cretonne/src/verifier/liveness.rs

@@ -8,6 +8,7 @@ use regalloc::liveness::Liveness;
 use regalloc::liverange::LiveRange;
 use std::cmp::Ordering;
 use verifier::Result;
+use timing;
 
 /// Verify liveness information for `func`.
 ///
@@ -27,6 +28,7 @@ pub fn verify_liveness(
     cfg: &ControlFlowGraph,
     liveness: &Liveness,
 ) -> Result {
+    let _tt = timing::verify_liveness();
     let verifier = LivenessVerifier {
         isa,
         func,

lib/cretonne/src/verifier/locations.rs

@@ -5,6 +5,7 @@ use isa;
 use regalloc::RegDiversions;
 use regalloc::liveness::Liveness;
 use verifier::Result;
+use timing;
 
 /// Verify value locations for `func`.
 ///
@@ -22,6 +23,7 @@ pub fn verify_locations(
     func: &ir::Function,
     liveness: Option<&Liveness>,
 ) -> Result {
+    let _tt = timing::verify_locations();
     let verifier = LocationVerifier {
         isa,
         func,

lib/cretonne/src/verifier/mod.rs

@@ -73,6 +73,7 @@ use std::collections::BTreeSet;
 use std::error as std_error;
 use std::fmt::{self, Display, Formatter, Write};
 use std::result;
+use timing;
 
 pub use self::cssa::verify_cssa;
 pub use self::liveness::verify_liveness;
@@ -126,6 +127,7 @@ pub type Result = result::Result<(), Error>;
 
 /// Verify `func`.
 pub fn verify_function<'a, FOI: Into<FlagsOrIsa<'a>>>(func: &Function, fisa: FOI) -> Result {
+    let _tt = timing::verifier();
     Verifier::new(func, fisa.into()).run()
 }
 
@@ -137,6 +139,7 @@ pub fn verify_context<'a, FOI: Into<FlagsOrIsa<'a>>>(
     domtree: &DominatorTree,
     fisa: FOI,
 ) -> Result {
+    let _tt = timing::verifier();
     let verifier = Verifier::new(func, fisa.into());
     if cfg.is_valid() {
         verifier.cfg_integrity(cfg)?;