Rollup merge of rust-lang#42225 - brson:vs2017, r=alexcrichton

Support VS 2017

Fixes rust-lang#38584

This replaces all the MSVC linker logic with that from the 'gcc' crate. The code looks the same, but there could be regressions.

I've only tested this with x86_64.

r? @alexcrichton
cc @vadimcn @retep998

src/bootstrap/Cargo.toml

@@ -36,5 +36,5 @@ num_cpus = "1.0"
 toml = "0.1"
 getopts = "0.2"
 rustc-serialize = "0.3"
-gcc = "0.3.46"
+gcc = "0.3.50"
 libc = "0.2"

src/liballoc_jemalloc/Cargo.toml

@@ -17,7 +17,7 @@ libc = { path = "../rustc/libc_shim" }
 
 [build-dependencies]
 build_helper = { path = "../build_helper" }
-gcc = "0.3.27"
+gcc = "0.3.50"
 
 [features]
 debug = []

src/libcompiler_builtins/Cargo.toml

@@ -16,4 +16,4 @@ core = { path = "../libcore" }
 
 [build-dependencies]
 build_helper = { path = "../build_helper" }
-gcc = "0.3.27"
+gcc = "0.3.50"

src/libflate/Cargo.toml

@@ -11,4 +11,4 @@ crate-type = ["dylib"]
 
 [build-dependencies]
 build_helper = { path = "../build_helper" }
-gcc = "0.3.27"
+gcc = "0.3.50"

src/librustc_llvm/Cargo.toml

@@ -17,4 +17,4 @@ rustc_bitflags = { path = "../librustc_bitflags" }
 
 [build-dependencies]
 build_helper = { path = "../build_helper" }
-gcc = "0.3.27"
+gcc = "0.3.50"

src/librustc_trans/Cargo.toml

@@ -25,3 +25,6 @@ rustc_platform_intrinsics = { path = "../librustc_platform_intrinsics" }
 serialize = { path = "../libserialize" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
+
+[target."cfg(windows)".dependencies]
+gcc = "0.3.50"

src/librustc_trans/back/link.rs

@@ -12,7 +12,6 @@ use super::archive::{ArchiveBuilder, ArchiveConfig};
 use super::linker::Linker;
 use super::rpath::RPathConfig;
 use super::rpath;
-use super::msvc;
 use metadata::METADATA_FILENAME;
 use rustc::session::config::{self, NoDebugInfo, OutputFilenames, Input, OutputType};
 use rustc::session::filesearch;
@@ -142,20 +141,41 @@ pub fn build_link_meta(incremental_hashes_map: &IncrementalHashesMap) -> LinkMet
     return r;
 }
 
-// The third parameter is for an extra path to add to PATH for MSVC
-// cross linkers for host toolchain DLL dependencies
-pub fn get_linker(sess: &Session) -> (String, Command, Option<PathBuf>) {
+// The third parameter is for an env vars, used to set up the path for MSVC
+// to find its DLLs
+pub fn get_linker(sess: &Session) -> (String, Command, Vec<(OsString, OsString)>) {
     if let Some(ref linker) = sess.opts.cg.linker {
-        (linker.clone(), Command::new(linker), None)
+        (linker.clone(), Command::new(linker), vec![])
     } else if sess.target.target.options.is_like_msvc {
-        let (cmd, host) = msvc::link_exe_cmd(sess);
-        ("link.exe".to_string(), cmd, host)
+        let (cmd, envs) = msvc_link_exe_cmd(sess);
+        ("link.exe".to_string(), cmd, envs)
     } else {
         (sess.target.target.options.linker.clone(),
-         Command::new(&sess.target.target.options.linker), None)
+         Command::new(&sess.target.target.options.linker), vec![])
     }
 }
 
+#[cfg(windows)]
+pub fn msvc_link_exe_cmd(sess: &Session) -> (Command, Vec<(OsString, OsString)>) {
+    use gcc::windows_registry;
+
+    let target = &sess.opts.target_triple;
+    let tool = windows_registry::find_tool(target, "link.exe");
+
+    if let Some(tool) = tool {
+        let envs = tool.env().to_vec();
+        (tool.to_command(), envs)
+    } else {
+        debug!("Failed to locate linker.");
+        (Command::new("link.exe"), vec![])
+    }
+}
+
+#[cfg(not(windows))]
+pub fn msvc_link_exe_cmd(_sess: &Session) -> (Command, Vec<(OsString, OsString)>) {
+    (Command::new("link.exe"), vec![])
+}
+
 pub fn get_ar_prog(sess: &Session) -> String {
     sess.opts.cg.ar.clone().unwrap_or_else(|| {
         sess.target.target.options.ar.clone()
@@ -706,8 +726,9 @@ fn link_natively(sess: &Session,
     let flavor = sess.linker_flavor();
 
     // The invocations of cc share some flags across platforms
-    let (pname, mut cmd, extra) = get_linker(sess);
-    cmd.env("PATH", command_path(sess, extra));
+    let (pname, mut cmd, envs) = get_linker(sess);
+    // This will set PATH on MSVC
+    cmd.envs(envs);
 
     let root = sess.target_filesearch(PathKind::Native).get_lib_path();
     if let Some(args) = sess.target.target.options.pre_link_args.get(&flavor) {