From cb9675259fd5b807d63a3986154031d38276c2dd Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Mon, 14 Nov 2011 14:03:20 -0800
Subject: [PATCH] enable comments in generated asm, ll

---
 src/comp/driver/rustc.rs       | 12 ++++++++++--
 src/comp/driver/session.rs     |  3 ++-
 src/comp/middle/trans.rs       |  4 +++-
 src/comp/middle/trans_build.rs | 23 +++++++++++++++++++++--
 4 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/src/comp/driver/rustc.rs b/src/comp/driver/rustc.rs
index 7ba36436d228..3623f451e9d8 100644
--- a/src/comp/driver/rustc.rs
+++ b/src/comp/driver/rustc.rs
@@ -263,6 +263,7 @@ options:
     --opt-level <lvl>  optimize with possible levels 0-3
     -O                 equivalent to --opt-level=2
     -S                 compile only; do not assemble or link
+    --no-asm-comments  do not add comments into the assembly source
     -c                 compile and assemble, but do not link
     --emit-llvm        produce an LLVM bitcode file
     --save-temps       write intermediate files in addition to normal output
@@ -365,6 +366,11 @@ fn build_session_options(match: getopts::match)
     let run_typestate = !opt_present(match, "no-typestate");
     let sysroot_opt = getopts::opt_maybe_str(match, "sysroot");
     let target_opt = getopts::opt_maybe_str(match, "target");
+    let no_asm_comments = getopts::opt_present(match, "no-asm-comments");
+    alt output_type { // unless we're emitting huamn-readable assembly, omit comments.
+      link::output_type_llvm_assembly. | link::output_type_assembly. {}
+      _ { no_asm_comments = true; }
+    }
     let opt_level: uint =
         if opt_present(match, "O") {
             if opt_present(match, "opt-level") {
@@ -414,7 +420,8 @@ fn build_session_options(match: getopts::match)
           parse_only: parse_only,
           no_trans: no_trans,
           do_gc: do_gc,
-          stack_growth: stack_growth};
+          stack_growth: stack_growth,
+          no_asm_comments: no_asm_comments};
     ret sopts;
 }
 
@@ -453,7 +460,8 @@ fn opts() -> [getopts::opt] {
          optflag("no-typestate"), optflag("noverify"),
          optmulti("cfg"), optflag("test"),
          optflag("lib"), optflag("static"), optflag("gc"),
-         optflag("stack-growth")];
+         optflag("stack-growth"), optflag("check-unsafe"),
+         optflag("no-asm-comments")];
 }
 
 fn build_output_filenames(ifile: str, ofile: option::t<str>,
diff --git a/src/comp/driver/session.rs b/src/comp/driver/session.rs
index a1fd65c44e7c..9793dae65d77 100644
--- a/src/comp/driver/session.rs
+++ b/src/comp/driver/session.rs
@@ -43,7 +43,8 @@ type options =
      parse_only: bool,
      no_trans: bool,
      do_gc: bool,
-     stack_growth: bool};
+     stack_growth: bool,
+     no_asm_comments: bool};
 
 type crate_metadata = {name: str, data: [u8]};
 
diff --git a/src/comp/middle/trans.rs b/src/comp/middle/trans.rs
index 60225b35a520..a6e1f5dbde54 100644
--- a/src/comp/middle/trans.rs
+++ b/src/comp/middle/trans.rs
@@ -24,7 +24,7 @@ import back::{link, abi, upcall};
 import syntax::{ast, ast_util};
 import syntax::visit;
 import syntax::codemap::span;
-import syntax::print::pprust::{expr_to_str};
+import syntax::print::pprust::{expr_to_str, path_to_str, stmt_to_str};
 import visit::vt;
 import util::common::*;
 import lib::llvm::{llvm, mk_target_data, mk_type_names};
@@ -4605,6 +4605,8 @@ fn zero_alloca(cx: @block_ctxt, llptr: ValueRef, t: ty::t)
 fn trans_stmt(cx: @block_ctxt, s: ast::stmt) -> @block_ctxt {
     // FIXME Fill in cx.sp
 
+    add_span_comment(cx, s.span, stmt_to_str(s));
+
     let bcx = cx;
     alt s.node {
       ast::stmt_expr(e, _) { bcx = trans_expr(cx, e, ignore); }
diff --git a/src/comp/middle/trans_build.rs b/src/comp/middle/trans_build.rs
index e888b00fa3a7..69ef397f9e13 100644
--- a/src/comp/middle/trans_build.rs
+++ b/src/comp/middle/trans_build.rs
@@ -1,10 +1,11 @@
 import std::{vec, str};
 import std::str::sbuf;
 import lib::llvm::llvm;
+import syntax::codemap::span;
 import llvm::{ValueRef, TypeRef, BasicBlockRef, BuilderRef, Opcode,
               ModuleRef};
-import trans_common::{block_ctxt, T_ptr, T_nil, T_i8, T_i1,
-                      val_ty, C_i32};
+import trans_common::{block_ctxt, T_ptr, T_nil, T_int, T_i8, T_i1, T_void,
+                      T_fn, val_ty, bcx_ccx, C_i32};
 
 fn B(cx: @block_ctxt) -> BuilderRef {
     let b = *cx.fcx.lcx.ccx.builder;
@@ -504,6 +505,24 @@ fn _UndefReturn(cx: @block_ctxt, Fn: ValueRef) -> ValueRef {
     ret llvm::LLVMGetUndef(retty);
 }
 
+fn add_span_comment(bcx: @block_ctxt, sp: span, text: str) {
+    let ccx = bcx_ccx(bcx);
+    if (!ccx.sess.get_opts().no_asm_comments) {
+        add_comment(bcx, text + " (" + ccx.sess.span_str(sp) + ")");
+    }
+}
+
+fn add_comment(bcx: @block_ctxt, text: str) {
+    let ccx = bcx_ccx(bcx);
+    if (!ccx.sess.get_opts().no_asm_comments) {
+        let comment_text = "; " + text;
+        let asm = str::as_buf(comment_text, { |c|
+            str::as_buf("", { |e|
+                llvm::LLVMConstInlineAsm(T_fn([], T_void()), c, e, 0, 0)})});
+        Call(bcx, asm, []);
+    }
+}
+
 fn Call(cx: @block_ctxt, Fn: ValueRef, Args: [ValueRef]) -> ValueRef {
     if cx.unreachable { ret _UndefReturn(cx, Fn); }
     unsafe {