make asm_comments something that you opt in to

src/librustc/driver/driver.rs

@@ -600,11 +600,6 @@ pub fn build_session_options(binary: @~str,
     let target_opt = getopts::opt_maybe_str(matches, ~"target");
     let target_feature_opt = getopts::opt_maybe_str(matches, ~"target-feature");
     let save_temps = getopts::opt_present(matches, ~"save-temps");
-    match output_type {
-      // unless we're emitting huamn-readable assembly, omit comments.
-      link::output_type_llvm_assembly | link::output_type_assembly => (),
-      _ => debugging_opts |= session::no_asm_comments
-    }
     let opt_level = {
         if (debugging_opts & session::no_opt) != 0 {
             No

src/librustc/driver/session.rs

@@ -45,7 +45,7 @@ pub static time_passes: uint = 1 << 1;
 pub static count_llvm_insns: uint = 1 << 2;
 pub static time_llvm_passes: uint = 1 << 3;
 pub static trans_stats: uint = 1 << 4;
-pub static no_asm_comments: uint = 1 << 5;
+pub static asm_comments: uint = 1 << 5;
 pub static no_verify: uint = 1 << 6;
 pub static trace: uint = 1 << 7;
 pub static coherence: uint = 1 << 8;
@@ -72,7 +72,7 @@ pub fn debugging_opts_map() -> ~[(~str, ~str, uint)] {
      (~"time-llvm-passes", ~"measure time of each LLVM pass",
       time_llvm_passes),
      (~"trans-stats", ~"gather trans statistics", trans_stats),
-     (~"no-asm-comments", ~"omit comments when using -S", no_asm_comments),
+     (~"asm-comments", ~"generate comments into the assembly (may change behavior)", asm_comments),
      (~"no-verify", ~"skip LLVM verification", no_verify),
      (~"trace", ~"emit trace logs", trace),
      (~"coherence", ~"perform coherence checking", coherence),
@@ -267,7 +267,7 @@ pub impl Session_ {
     }
     fn trans_stats(@self) -> bool { self.debugging_opt(trans_stats) }
     fn meta_stats(@self) -> bool { self.debugging_opt(meta_stats) }
-    fn no_asm_comments(@self) -> bool { self.debugging_opt(no_asm_comments) }
+    fn asm_comments(@self) -> bool { self.debugging_opt(asm_comments) }
     fn no_verify(@self) -> bool { self.debugging_opt(no_verify) }
     fn trace(@self) -> bool { self.debugging_opt(trace) }
     fn coherence(@self) -> bool { self.debugging_opt(coherence) }

src/librustc/middle/borrowck/check_loans.rs

@@ -374,7 +374,7 @@ pub impl<'self> CheckLoanCtxt<'self> {
                     }
                 }
 
-                mc::cat_deref(base, deref_count, mc::gc_ptr(ast::m_mutbl)) => {
+                mc::cat_deref(_, deref_count, mc::gc_ptr(ast::m_mutbl)) => {
                     // Dynamically check writes to `@mut`
 
                     let key = root_map_key {

src/librustc/middle/mem_categorization.rs

@@ -378,7 +378,6 @@ pub impl mem_categorization_ctxt {
         debug!("cat_expr: id=%d expr=%s",
                expr.id, pprust::expr_to_str(expr, self.tcx.sess.intr()));
 
-        let tcx = self.tcx;
         let expr_ty = self.expr_ty(expr);
         match expr.node {
           ast::expr_unary(ast::deref, e_base) => {

src/librustc/middle/trans/base.rs

@@ -1133,7 +1133,7 @@ pub fn trans_stmt(cx: block, s: &ast::stmt) -> block {
     let _icx = cx.insn_ctxt("trans_stmt");
     debug!("trans_stmt(%s)", stmt_to_str(s, cx.tcx().sess.intr()));
 
-    if !cx.sess().no_asm_comments() {
+    if cx.sess().asm_comments() {
         add_span_comment(cx, s.span, stmt_to_str(s, cx.ccx().sess.intr()));
     }
 

src/librustc/middle/trans/build.rs

@@ -846,7 +846,7 @@ pub fn _UndefReturn(cx: block, Fn: ValueRef) -> ValueRef {
 
 pub fn add_span_comment(bcx: block, sp: span, text: &str) {
     let ccx = bcx.ccx();
-    if !ccx.sess.no_asm_comments() {
+    if ccx.sess.asm_comments() {
         let s = fmt!("%s (%s)", text, ccx.sess.codemap.span_to_str(sp));
         debug!("%s", copy s);
         add_comment(bcx, s);
@@ -856,7 +856,7 @@ pub fn add_span_comment(bcx: block, sp: span, text: &str) {
 pub fn add_comment(bcx: block, text: &str) {
     unsafe {
         let ccx = bcx.ccx();
-        if !ccx.sess.no_asm_comments() {
+        if ccx.sess.asm_comments() {
             let sanitized = str::replace(text, ~"$", ~"");
             let comment_text = ~"# " +
                 str::replace(sanitized, ~"\n", ~"\n\t# ");

src/librustc/middle/trans/closure.rs

@@ -224,7 +224,7 @@ pub fn store_environment(bcx: block,
     for vec::eachi(bound_values) |i, bv| {
         debug!("Copy %s into closure", bv.to_str(ccx));
 
-        if !ccx.sess.no_asm_comments() {
+        if ccx.sess.asm_comments() {
             add_comment(bcx, fmt!("Copy %s into closure",
                                   bv.to_str(ccx)));
         }