Stabilize linker-flavor flag.

This commit moves the linker-flavor flag from a debugging option to a
codegen option, thus stabilizing it. There are no feature flags
associated with this flag.

src/doc/rustc/src/codegen-options/index.md

@@ -22,6 +22,13 @@ This flag lets you append a single extra argument to the linker invocation.
 This flag lets you append multiple extra arguments to the linker invocation. The
 options should be separated by spaces.
 
+## linker-flavor
+
+This flag lets you control the linker flavor used by `rustc`. If a linker is given with the
+`-C linker` flag described above then the linker flavor is inferred from the value provided. If no
+linker is given then the linker flavor is used to determine the linker to use. Every `rustc` target
+defaults to some linker flavor.
+
 ## link-dead-code
 
 Normally, the linker will remove dead code. This flag disables this behavior.

src/doc/unstable-book/src/compiler-flags/linker-flavor.md

@@ -1,61 +0,0 @@
-# `linker-flavor`
-
-The tracking issue for this feature is: None
-
-------------------------
-
-Every `rustc` target defaults to some linker. For example, Linux targets default
-to gcc. In some cases, you may want to override the default; you can do that
-with the unstable CLI argument: `-Z linker-flavor`.
-
-Here how you would use this flag to link a Rust binary for the
-`thumbv7m-none-eabi` using LLD instead of GCC.
-
-``` text
-$ xargo rustc --target thumbv7m-none-eabi -- \
-    -C linker=ld.lld \
-    -Z linker-flavor=ld \
-    -Z print-link-args | tr ' ' '\n'
-"ld.lld"
-"-L"
-"$SYSROOT/lib/rustlib/thumbv7m-none-eabi/lib"
-"$PWD/target/thumbv7m-none-eabi/debug/deps/app-512e9dbf385f233c.0.o"
-"-o"
-"$PWD/target/thumbv7m-none-eabi/debug/deps/app-512e9dbf385f233c"
-"--gc-sections"
-"-L"
-"$PWD/target/thumbv7m-none-eabi/debug/deps"
-"-L"
-"$PWD/target/debug/deps"
-"-L"
-"$SYSROOT/lib/rustlib/thumbv7m-none-eabi/lib"
-"-Bstatic"
-"$SYSROOT/lib/rustlib/thumbv7m-none-eabi/lib/libcore-e1ccb7dfb1cb9ebb.rlib"
-"-Bdynamic"
-```
-
-Whereas the default is:
-
-``` text
-$ xargo rustc --target thumbv7m-none-eabi -- \
-    -C link-arg=-nostartfiles \
-    -Z print-link-args | tr ' ' '\n'
-"arm-none-eabi-gcc"
-"-L"
-"$SYSROOT/lib/rustlib/thumbv7m-none-eabi/lib"
-"$PWD/target/thumbv7m-none-eabi/debug/deps/app-961e39416baa38d9.0.o"
-"-o"
-"$PWD/target/thumbv7m-none-eabi/debug/deps/app-961e39416baa38d9"
-"-Wl,--gc-sections"
-"-nodefaultlibs"
-"-L"
-"$PWD/target/thumbv7m-none-eabi/debug/deps"
-"-L"
-"$PWD/target/debug/deps"
-"-L"
-"$SYSROOT/lib/rustlib/thumbv7m-none-eabi/lib"
-"-Wl,-Bstatic"
-"$SYSROOT/lib/rustlib/thumbv7m-none-eabi/lib/libcore-e1ccb7dfb1cb9ebb.rlib"
-"-nostartfiles"
-"-Wl,-Bdynamic"
-```

src/librustc/session/config.rs

@@ -1136,6 +1136,8 @@ options! {CodegenOptions, CodegenSetter, basic_codegen_options,
         "enable incremental compilation"),
     default_linker_libraries: Option<bool> = (None, parse_opt_bool, [UNTRACKED],
         "allow the linker to link its default libraries"),
+    linker_flavor: Option<LinkerFlavor> = (None, parse_linker_flavor, [UNTRACKED],
+                                           "Linker flavor"),
 }
 
 options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
@@ -1292,8 +1294,6 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "pass `-install_name @rpath/...` to the macOS linker"),
     sanitizer: Option<Sanitizer> = (None, parse_sanitizer, [TRACKED],
                                     "Use a sanitizer"),
-    linker_flavor: Option<LinkerFlavor> = (None, parse_linker_flavor, [UNTRACKED],
-                                           "Linker flavor"),
     fuel: Option<(String, u64)> = (None, parse_optimization_fuel, [TRACKED],
         "set the optimization fuel quota for a crate"),
     print_fuel: Option<String> = (None, parse_opt_string, [TRACKED],

src/librustc_codegen_ssa/back/link.rs

@@ -192,11 +192,7 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) {
 
     // linker and linker flavor specified via command line have precedence over what the target
     // specification specifies
-    if let Some(ret) = infer_from(
-        sess,
-        sess.opts.cg.linker.clone(),
-        sess.opts.debugging_opts.linker_flavor,
-    ) {
+    if let Some(ret) = infer_from(sess, sess.opts.cg.linker.clone(), sess.opts.cg.linker_flavor) {
         return ret;
     }
 

src/test/compile-fail/issue-10755.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -C linker=llllll -Z linker-flavor=ld
+// compile-flags: -C linker=llllll -C linker-flavor=ld
 // error-pattern: linker `llllll` not found
 
 fn main() {

src/test/compile-fail/nolink-with-link-args.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 // error-pattern:aFdEfSeVEE
-// compile-flags: -Z linker-flavor=ld
+// compile-flags: -C linker-flavor=ld
 
 /* We're testing that link_args are indeed passed when nolink is specified.
 So we try to compile with junk link_args and make sure they are visible in

src/test/ui/feature-gates/feature-gate-linker-flavor.rs

@@ -1,20 +0,0 @@
-// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// This is a fake compile fail test as there's no way to generate a
-// `#![feature(linker_flavor)]` error. The only reason we have a `linker_flavor`
-// feature gate is to be able to document `-Z linker-flavor` in the unstable
-// book
-
-#[used]
-//~^ ERROR attribute must be applied to a `static` variable
-fn foo() {}
-
-fn main() {}

src/test/ui/feature-gates/feature-gate-linker-flavor.stderr

@@ -1,8 +0,0 @@
-error: attribute must be applied to a `static` variable
-  --> $DIR/feature-gate-linker-flavor.rs:16:1
-   |
-LL | #[used]
-   | ^^^^^^^
-
-error: aborting due to previous error
-