rustdoc: Add a --target flag

Closes #13893

src/librustdoc/core.rs

@@ -80,7 +80,8 @@ pub struct CrateAnalysis {
 pub type Externs = HashMap<String, Vec<String>>;
 
 /// Parses, resolves, and typechecks the given crate
-fn get_ast_and_resolve(cpath: &Path, libs: HashSet<Path>, cfgs: Vec<String>, externs: Externs)
+fn get_ast_and_resolve(cpath: &Path, libs: HashSet<Path>, cfgs: Vec<String>,
+                       externs: Externs, triple: Option<String>)
                        -> (DocContext, CrateAnalysis) {
     use syntax::codemap::dummy_spanned;
     use rustc::driver::driver::{FileInput,
@@ -99,6 +100,7 @@ fn get_ast_and_resolve(cpath: &Path, libs: HashSet<Path>, cfgs: Vec<String>, ext
         crate_types: vec!(driver::config::CrateTypeRlib),
         lint_opts: vec!((warning_lint, lint::Allow)),
         externs: externs,
+        target_triple: triple.unwrap_or(driver::driver::host_triple().to_string()),
         ..rustc::driver::config::basic_options().clone()
     };
 
@@ -151,9 +153,10 @@ fn get_ast_and_resolve(cpath: &Path, libs: HashSet<Path>, cfgs: Vec<String>, ext
     })
 }
 
-pub fn run_core(libs: HashSet<Path>, cfgs: Vec<String>, externs: Externs, path: &Path)
+pub fn run_core(libs: HashSet<Path>, cfgs: Vec<String>, externs: Externs,
+                path: &Path, triple: Option<String>)
                 -> (clean::Crate, CrateAnalysis) {
-    let (ctxt, analysis) = get_ast_and_resolve(path, libs, cfgs, externs);
+    let (ctxt, analysis) = get_ast_and_resolve(path, libs, cfgs, externs, triple);
     let ctxt = box(GC) ctxt;
     super::ctxtkey.replace(Some(ctxt));
 

src/librustdoc/lib.rs

@@ -117,6 +117,7 @@ pub fn opts() -> Vec<getopts::OptGroup> {
         optflag("", "test", "run code examples as tests"),
         optmulti("", "test-args", "arguments to pass to the test runner",
                  "ARGS"),
+        optopt("", "target", "target triple to document", "TRIPLE"),
         optmulti("", "markdown-css", "CSS files to include via <link> in a rendered Markdown file",
                  "FILES"),
         optmulti("", "html-in-header",
@@ -321,6 +322,7 @@ fn rust_input(cratefile: &str, externs: core::Externs, matches: &getopts::Matche
                                  .map(|s| Path::new(s.as_slice()))
                                  .collect();
     let cfgs = matches.opt_strs("cfg");
+    let triple = matches.opt_str("target");
 
     let cr = Path::new(cratefile);
     info!("starting to run rustc");
@@ -329,7 +331,8 @@ fn rust_input(cratefile: &str, externs: core::Externs, matches: &getopts::Matche
         core::run_core(libs.move_iter().collect(),
                        cfgs,
                        externs,
-                       &cr)
+                       &cr,
+                       triple)
     }).map_err(|boxed_any|format!("{:?}", boxed_any)).unwrap();
     info!("finished with rustc");
     analysiskey.replace(Some(analysis));