Auto merge of #34208 - shepmaster:llvm-3.7-linking-intrinsics, r=alexcrichton

Remove linking and intrinsics code made dead by only supporting LLVM 3.7 and up

This is mostly based on Alex's throwaway comment:

> probably reject those that LLVM just doesn't support...

So I'm more than happy to adjust the PR based on how you thought this should look. Also happy to split it into two PRs, one for linking and one for intrinsics.

r? @alexcrichton

/cc @nagisa @brson

src/librustc_llvm/lib.rs

@@ -54,6 +54,7 @@ pub use self::DiagnosticSeverity::*;
 pub use self::Linkage::*;
 pub use self::DLLStorageClassTypes::*;
 
+use std::str::FromStr;
 use std::ffi::{CString, CStr};
 use std::cell::RefCell;
 use std::slice;
@@ -426,6 +427,20 @@ pub enum ArchiveKind {
     K_COFF,
 }
 
+impl FromStr for ArchiveKind {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "gnu" => Ok(ArchiveKind::K_GNU),
+            "mips64" => Ok(ArchiveKind::K_MIPS64),
+            "bsd" => Ok(ArchiveKind::K_BSD),
+            "coff" => Ok(ArchiveKind::K_COFF),
+            _ => Err(()),
+        }
+    }
+}
+
 /// Represents the different LLVM passes Rust supports
 #[derive(Copy, Clone, PartialEq, Debug)]
 #[repr(C)]

src/librustc_trans/back/archive.rs

@@ -10,14 +10,10 @@
 
 //! A helper class for dealing with static archives
 
-use std::env;
 use std::ffi::{CString, CStr, OsString};
-use std::fs::{self, File};
-use std::io::prelude::*;
 use std::io;
 use std::mem;
 use std::path::{Path, PathBuf};
-use std::process::{Command, Output, Stdio};
 use std::ptr;
 use std::str;
 
@@ -25,7 +21,6 @@ use libc;
 use llvm::archive_ro::{ArchiveRO, Child};
 use llvm::{self, ArchiveKind};
 use rustc::session::Session;
-use rustc_back::tempdir::TempDir;
 
 pub struct ArchiveConfig<'a> {
     pub sess: &'a Session,
@@ -41,7 +36,6 @@ pub struct ArchiveConfig<'a> {
 #[must_use = "must call build() to finish building the archive"]
 pub struct ArchiveBuilder<'a> {
     config: ArchiveConfig<'a>,
-    work_dir: TempDir,
     removals: Vec<String>,
     additions: Vec<Addition>,
     should_update_symbols: bool,
@@ -55,17 +49,10 @@ enum Addition {
     },
     Archive {
         archive: ArchiveRO,
-        archive_name: String,
         skip: Box<FnMut(&str) -> bool>,
     },
 }
 
-enum Action<'a> {
-    Remove(&'a [String]),
-    AddObjects(&'a [&'a PathBuf], bool),
-    UpdateSymbols,
-}
-
 pub fn find_library(name: &str, search_paths: &[PathBuf], sess: &Session)
                     -> PathBuf {
     // On Windows, static libraries sometimes show up as libfoo.a and other
@@ -102,7 +89,6 @@ impl<'a> ArchiveBuilder<'a> {
     pub fn new(config: ArchiveConfig<'a>) -> ArchiveBuilder<'a> {
         ArchiveBuilder {
             config: config,
-            work_dir: TempDir::new("rsar").unwrap(),
             removals: Vec::new(),
             additions: Vec::new(),
             should_update_symbols: false,
@@ -148,7 +134,7 @@ impl<'a> ArchiveBuilder<'a> {
     pub fn add_native_library(&mut self, name: &str) {
         let location = find_library(name, &self.config.lib_search_paths,
                                     self.config.sess);
-        self.add_archive(&location, name, |_| false).unwrap_or_else(|e| {
+        self.add_archive(&location, |_| false).unwrap_or_else(|e| {
             self.config.sess.fatal(&format!("failed to add native library {}: {}",
                                             location.to_string_lossy(), e));
         });
@@ -172,14 +158,14 @@ impl<'a> ArchiveBuilder<'a> {
         let metadata_filename =
             self.config.sess.cstore.metadata_filename().to_owned();
 
-        self.add_archive(rlib, &name[..], move |fname: &str| {
+        self.add_archive(rlib, move |fname: &str| {
             let skip_obj = lto && fname.starts_with(&obj_start)
                 && fname.ends_with(".o");
             skip_obj || fname.ends_with(bc_ext) || fname == metadata_filename
         })
     }
 
-    fn add_archive<F>(&mut self, archive: &Path, name: &str, skip: F)
+    fn add_archive<F>(&mut self, archive: &Path, skip: F)
                       -> io::Result<()>
         where F: FnMut(&str) -> bool + 'static
     {
@@ -190,7 +176,6 @@ impl<'a> ArchiveBuilder<'a> {
         };
         self.additions.push(Addition::Archive {
             archive: archive,
-            archive_name: name.to_string(),
             skip: Box::new(skip),
         });
         Ok(())
@@ -214,234 +199,23 @@ impl<'a> ArchiveBuilder<'a> {
     /// Combine the provided files, rlibs, and native libraries into a single
     /// `Archive`.
     pub fn build(&mut self) {
-        let res = match self.llvm_archive_kind() {
+        let kind = match self.llvm_archive_kind() {
-            Some(kind) => self.build_with_llvm(kind),
+            Ok(kind) => kind,
-            None => self.build_with_ar_cmd(),
+            Err(kind) => {
+                self.config.sess.fatal(&format!("Don't know how to build archive of type: {}",
+                                                kind));
+            }
         };
-        if let Err(e) = res {
+
+        if let Err(e) = self.build_with_llvm(kind) {
             self.config.sess.fatal(&format!("failed to build archive: {}", e));
         }
+
     }
 
-    pub fn llvm_archive_kind(&self) -> Option<ArchiveKind> {
+    fn llvm_archive_kind(&self) -> Result<ArchiveKind, &str> {
-        if unsafe { llvm::LLVMVersionMinor() < 7 } {
+        let kind = &self.config.sess.target.target.options.archive_format[..];
-            return None
+        kind.parse().map_err(|_| kind)
-        }
-
-        // Currently LLVM only supports writing archives in the 'gnu' format.
-        match &self.config.sess.target.target.options.archive_format[..] {
-            "gnu" => Some(ArchiveKind::K_GNU),
-            "mips64" => Some(ArchiveKind::K_MIPS64),
-            "bsd" => Some(ArchiveKind::K_BSD),
-            "coff" => Some(ArchiveKind::K_COFF),
-            _ => None,
-        }
-    }
-
-    pub fn using_llvm(&self) -> bool {
-        self.llvm_archive_kind().is_some()
-    }
-
-    fn build_with_ar_cmd(&mut self) -> io::Result<()> {
-        let removals = mem::replace(&mut self.removals, Vec::new());
-        let additions = mem::replace(&mut self.additions, Vec::new());
-        let should_update_symbols = mem::replace(&mut self.should_update_symbols,
-                                                 false);
-
-        // Don't use fs::copy because libs may be installed as read-only and we
-        // want to modify this archive, so we use `io::copy` to not preserve
-        // permission bits.
-        if let Some(ref s) = self.config.src {
-            io::copy(&mut File::open(s)?,
-                     &mut File::create(&self.config.dst)?)?;
-        }
-
-        if removals.len() > 0 {
-            self.run(None, Action::Remove(&removals));
-        }
-
-        let mut members = Vec::new();
-        for addition in additions {
-            match addition {
-                Addition::File { path, name_in_archive } => {
-                    let dst = self.work_dir.path().join(&name_in_archive);
-                    fs::copy(&path, &dst)?;
-                    members.push(PathBuf::from(name_in_archive));
-                }
-                Addition::Archive { archive, archive_name, mut skip } => {
-                    self.add_archive_members(&mut members, archive,
-                                             &archive_name, &mut *skip)?;
-                }
-            }
-        }
-
-        // Get an absolute path to the destination, so `ar` will work even
-        // though we run it from `self.work_dir`.
-        let mut objects = Vec::new();
-        let mut total_len = self.config.dst.to_string_lossy().len();
-
-        if members.is_empty() {
-            if should_update_symbols {
-                self.run(Some(self.work_dir.path()), Action::UpdateSymbols);
-            }
-            return Ok(())
-        }
-
-        // Don't allow the total size of `args` to grow beyond 32,000 bytes.
-        // Windows will raise an error if the argument string is longer than
-        // 32,768, and we leave a bit of extra space for the program name.
-        const ARG_LENGTH_LIMIT: usize = 32_000;
-
-        for member_name in &members {
-            let len = member_name.to_string_lossy().len();
-
-            // `len + 1` to account for the space that's inserted before each
-            // argument.  (Windows passes command-line arguments as a single
-            // string, not an array of strings.)
-            if total_len + len + 1 > ARG_LENGTH_LIMIT {
-                // Add the archive members seen so far, without updating the
-                // symbol table.
-                self.run(Some(self.work_dir.path()),
-                         Action::AddObjects(&objects, false));
-
-                objects.clear();
-                total_len = self.config.dst.to_string_lossy().len();
-            }
-
-            objects.push(member_name);
-            total_len += len + 1;
-        }
-
-        // Add the remaining archive members, and update the symbol table if
-        // necessary.
-        self.run(Some(self.work_dir.path()),
-                         Action::AddObjects(&objects, should_update_symbols));
-        Ok(())
-    }
-
-    fn add_archive_members(&mut self, members: &mut Vec<PathBuf>,
-                           archive: ArchiveRO, name: &str,
-                           skip: &mut FnMut(&str) -> bool) -> io::Result<()> {
-        // Next, we must rename all of the inputs to "guaranteed unique names".
-        // We write each file into `self.work_dir` under its new unique name.
-        // The reason for this renaming is that archives are keyed off the name
-        // of the files, so if two files have the same name they will override
-        // one another in the archive (bad).
-        //
-        // We skip any files explicitly desired for skipping, and we also skip
-        // all SYMDEF files as these are just magical placeholders which get
-        // re-created when we make a new archive anyway.
-        for file in archive.iter() {
-            let file = file.map_err(string_to_io_error)?;
-            if !is_relevant_child(&file) {
-                continue
-            }
-            let filename = file.name().unwrap();
-            if skip(filename) {
-                continue
-            }
-            let filename = Path::new(filename).file_name().unwrap()
-                                              .to_str().unwrap();
-
-            // Archives on unix systems typically do not have slashes in
-            // filenames as the `ar` utility generally only uses the last
-            // component of a path for the filename list in the archive. On
-            // Windows, however, archives assembled with `lib.exe` will preserve
-            // the full path to the file that was placed in the archive,
-            // including path separators.
-            //
-            // The code below is munging paths so it'll go wrong pretty quickly
-            // if there's some unexpected slashes in the filename, so here we
-            // just chop off everything but the filename component. Note that
-            // this can cause duplicate filenames, but that's also handled below
-            // as well.
-            let filename = Path::new(filename).file_name().unwrap()
-                                              .to_str().unwrap();
-
-            // An archive can contain files of the same name multiple times, so
-            // we need to be sure to not have them overwrite one another when we
-            // extract them. Consequently we need to find a truly unique file
-            // name for us!
-            let mut new_filename = String::new();
-            for n in 0.. {
-                let n = if n == 0 {String::new()} else {format!("-{}", n)};
-                new_filename = format!("r{}-{}-{}", n, name, filename);
-
-                // LLDB (as mentioned in back::link) crashes on filenames of
-                // exactly
-                // 16 bytes in length. If we're including an object file with
-                //    exactly 16-bytes of characters, give it some prefix so
-                //    that it's not 16 bytes.
-                new_filename = if new_filename.len() == 16 {
-                    format!("lldb-fix-{}", new_filename)
-                } else {
-                    new_filename
-                };
-
-                let present = members.iter().filter_map(|p| {
-                    p.file_name().and_then(|f| f.to_str())
-                }).any(|s| s == new_filename);
-                if !present {
-                    break
-                }
-            }
-            let dst = self.work_dir.path().join(&new_filename);
-            File::create(&dst)?.write_all(file.data())?;
-            members.push(PathBuf::from(new_filename));
-        }
-        Ok(())
-    }
-
-    fn run(&self, cwd: Option<&Path>, action: Action) -> Output {
-        let abs_dst = env::current_dir().unwrap().join(&self.config.dst);
-        let ar = &self.config.ar_prog;
-        let mut cmd = Command::new(ar);
-        cmd.env("PATH", &self.config.command_path);
-        cmd.stdout(Stdio::piped()).stderr(Stdio::piped());
-        self.prepare_ar_action(&mut cmd, &abs_dst, action);
-        info!("{:?}", cmd);
-
-        if let Some(p) = cwd {
-            cmd.current_dir(p);
-            info!("inside {:?}", p.display());
-        }
-
-        let sess = &self.config.sess;
-        match cmd.spawn() {
-            Ok(prog) => {
-                let o = prog.wait_with_output().unwrap();
-                if !o.status.success() {
-                    sess.struct_err(&format!("{:?} failed with: {}", cmd, o.status))
-                        .note(&format!("stdout ---\n{}",
-                                       str::from_utf8(&o.stdout).unwrap()))
-                        .note(&format!("stderr ---\n{}",
-                                       str::from_utf8(&o.stderr).unwrap()))
-                        .emit();
-                    sess.abort_if_errors();
-                }
-                o
-            },
-            Err(e) => {
-                sess.fatal(&format!("could not exec `{}`: {}",
-                                    self.config.ar_prog, e));
-            }
-        }
-    }
-
-    fn prepare_ar_action(&self, cmd: &mut Command, dst: &Path, action: Action) {
-        match action {
-            Action::Remove(files) => {
-                cmd.arg("d").arg(dst).args(files);
-            }
-            Action::AddObjects(objs, update_symbols) => {
-                cmd.arg(if update_symbols {"crs"} else {"crS"})
-                   .arg(dst)
-                   .args(objs);
-            }
-            Action::UpdateSymbols => {
-                cmd.arg("s").arg(dst);
-            }
-        }
     }
 
     fn build_with_llvm(&mut self, kind: ArchiveKind) -> io::Result<()> {
@@ -480,7 +254,7 @@ impl<'a> ArchiveBuilder<'a> {
                         strings.push(path);
                         strings.push(name);
                     }
-                    Addition::Archive { archive, archive_name: _, mut skip } => {
+                    Addition::Archive { archive, mut skip } => {
                         for child in archive.iter() {
                             let child = child.map_err(string_to_io_error)?;
                             if !is_relevant_child(&child) {

src/librustc_trans/back/link.rs

@@ -412,13 +412,6 @@ fn link_rlib<'a>(sess: &'a Session,
     // symbol table of the archive.
     ab.update_symbols();
 
-    // For OSX/iOS, we must be careful to update symbols only when adding
-    // object files.  We're about to start adding non-object files, so run
-    // `ar` now to process the object files.
-    if sess.target.target.options.is_like_osx && !ab.using_llvm() {
-        ab.build();
-    }
-
     // Note that it is important that we add all of our non-object "magical
     // files" *after* all of the object files in the archive. The reason for
     // this is as follows:
@@ -515,7 +508,7 @@ fn link_rlib<'a>(sess: &'a Session,
             // After adding all files to the archive, we need to update the
             // symbol table of the archive. This currently dies on OSX (see
             // #11162), and isn't necessary there anyway
-            if !sess.target.target.options.is_like_osx || ab.using_llvm() {
+            if !sess.target.target.options.is_like_osx {
                 ab.update_symbols();
             }
         }
@@ -575,9 +568,6 @@ fn write_rlib_bytecode_object_v1(writer: &mut Write,
 fn link_staticlib(sess: &Session, objects: &[PathBuf], out_filename: &Path,
                   tempdir: &Path) {
     let mut ab = link_rlib(sess, None, objects, out_filename, tempdir);
-    if sess.target.target.options.is_like_osx && !ab.using_llvm() {
-        ab.build();
-    }
     if !sess.target.target.options.no_compiler_rt {
         ab.add_native_library("compiler-rt");
     }

src/librustc_trans/context.rs

@@ -1097,45 +1097,7 @@ fn declare_intrinsic(ccx: &CrateContext, key: &str) -> Option<ValueRef> {
     ifn!("llvm.localrecover", fn(i8p, i8p, t_i32) -> i8p);
     ifn!("llvm.x86.seh.recoverfp", fn(i8p, i8p) -> i8p);
 
-    // Some intrinsics were introduced in later versions of LLVM, but they have
+    ifn!("llvm.assume", fn(i1) -> void);
-    // fallbacks in libc or libm and such.
-    macro_rules! compatible_ifn {
-        ($name:expr, noop($cname:ident ($($arg:expr),*) -> void), $llvm_version:expr) => (
-            if unsafe { llvm::LLVMVersionMinor() >= $llvm_version } {
-                // The `if key == $name` is already in ifn!
-                ifn!($name, fn($($arg),*) -> void);
-            } else if key == $name {
-                let f = declare::declare_cfn(ccx, stringify!($cname),
-                                             Type::func(&[$($arg),*], &void));
-                llvm::SetLinkage(f, llvm::InternalLinkage);
-
-                let bld = ccx.builder();
-                let llbb = unsafe {
-                    llvm::LLVMAppendBasicBlockInContext(ccx.llcx(), f,
-                                                        "entry-block\0".as_ptr() as *const _)
-                };
-
-                bld.position_at_end(llbb);
-                bld.ret_void();
-
-                ccx.intrinsics().borrow_mut().insert($name, f.clone());
-                return Some(f);
-            }
-        );
-        ($name:expr, $cname:ident ($($arg:expr),*) -> $ret:expr, $llvm_version:expr) => (
-            if unsafe { llvm::LLVMVersionMinor() >= $llvm_version } {
-                // The `if key == $name` is already in ifn!
-                ifn!($name, fn($($arg),*) -> $ret);
-            } else if key == $name {
-                let f = declare::declare_cfn(ccx, stringify!($cname),
-                                             Type::func(&[$($arg),*], &$ret));
-                ccx.intrinsics().borrow_mut().insert($name, f.clone());
-                return Some(f);
-            }
-        )
-    }
-
-    compatible_ifn!("llvm.assume", noop(llvmcompat_assume(i1) -> void), 6);
 
     if ccx.sess().opts.debuginfo != NoDebugInfo {
         ifn!("llvm.dbg.declare", fn(Type::metadata(ccx), Type::metadata(ccx)) -> void);