Add -Zast and -Zast-noexpand to dump AST w/o JSON

-Zast behaves like -Zast-json but uses {:#?} pretty-printing instead of
converting to JSON.

-Zast-noexpand is the pretty-printing counterpart to -Zast-json-noexpand.

Author: spinda

src/librustc/session/config.rs

@@ -862,6 +862,10 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "print the arguments passed to the linker"),
     print_llvm_passes: bool = (false, parse_bool, [UNTRACKED],
         "prints the llvm optimization passes being run"),
+    ast: bool = (false, parse_bool, [UNTRACKED],
+        "pretty-print the AST and halt"),
+    ast_noexpand: bool = (false, parse_bool, [UNTRACKED],
+        "pretty-print the pre-expansion AST and halt"),
     ast_json: bool = (false, parse_bool, [UNTRACKED],
         "print the AST as JSON and halt"),
     ast_json_noexpand: bool = (false, parse_bool, [UNTRACKED],
@@ -2404,6 +2408,10 @@ mod tests {
         assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
         opts.debugging_opts.print_llvm_passes = true;
         assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
+        opts.debugging_opts.ast = true;
+        assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
+        opts.debugging_opts.ast_noexpand = true;
+        assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
         opts.debugging_opts.ast_json = true;
         assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
         opts.debugging_opts.ast_json_noexpand = true;

src/librustc_driver/driver.rs

@@ -501,6 +501,10 @@ pub fn phase_1_parse_input<'a>(sess: &'a Session, input: &Input) -> PResult<'a,
 
     sess.diagnostic().set_continue_after_error(true);
 
+    if sess.opts.debugging_opts.ast_noexpand {
+        println!("{:#?}", &krate);
+    }
+
     if sess.opts.debugging_opts.ast_json_noexpand {
         println!("{}", json::as_json(&krate));
     }
@@ -733,6 +737,10 @@ pub fn phase_2_configure_and_expand<F>(sess: &Session,
         hir_stats::print_ast_stats(&krate, "POST EXPANSION AST STATS");
     }
 
+    if sess.opts.debugging_opts.ast {
+        println!("{:#?}", &krate);
+    }
+
     if sess.opts.debugging_opts.ast_json {
         println!("{}", json::as_json(&krate));
     }

src/librustc_driver/lib.rs

@@ -484,11 +484,13 @@ impl<'a> CompilerCalls<'a> for RustcDefaultCalls {
 
         if sess.opts.debugging_opts.parse_only ||
            sess.opts.debugging_opts.show_span.is_some() ||
+           sess.opts.debugging_opts.ast_noexpand ||
            sess.opts.debugging_opts.ast_json_noexpand {
             control.after_parse.stop = Compilation::Stop;
         }
 
         if sess.opts.debugging_opts.no_analysis ||
+           sess.opts.debugging_opts.ast ||
            sess.opts.debugging_opts.ast_json {
             control.after_hir_lowering.stop = Compilation::Stop;
         }