fix LTO with doctests (backported cargo PR#8657)

0002-Fix-LTO-with-doctests.patch

@@ -0,0 +1,133 @@
+From 2c9deaabf99dab9998f6ddbbe496d19ff7ce31f0 Mon Sep 17 00:00:00 2001
+From: Fabio Valentini <decathorpe@gmail.com>
+Date: Fri, 28 Aug 2020 21:56:45 +0200
+Subject: [PATCH 2/2] Fix LTO with doctests
+
+---
+ .../src/cargo/core/compiler/context/mod.rs    |  3 +-
+ .../cargo/src/cargo/core/compiler/mod.rs      | 59 +++++----------
+ src/tools/cargo/src/cargo/core/profiles.rs    |  7 +-
+ src/tools/cargo/tests/testsuite/lto.rs        | 71 ++++++++++++++++---
+ 4 files changed, 85 insertions(+), 55 deletions(-)
+
+diff --git a/src/tools/cargo/src/cargo/core/compiler/context/mod.rs b/src/tools/cargo/src/cargo/core/compiler/context/mod.rs
+index 52b954dd1..82831f423 100644
+--- a/src/tools/cargo/src/cargo/core/compiler/context/mod.rs
++++ b/src/tools/cargo/src/cargo/core/compiler/context/mod.rs
+@@ -210,7 +210,8 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
+             // Collect information for `rustdoc --test`.
+             if unit.mode.is_doc_test() {
+                 let mut unstable_opts = false;
+-                let args = compiler::extern_args(&self, unit, &mut unstable_opts)?;
++                let mut args = compiler::extern_args(&self, unit, &mut unstable_opts)?;
++                args.extend(compiler::lto_args(&self, unit));
+                 self.compilation.to_doc_test.push(compilation::Doctest {
+                     unit: unit.clone(),
+                     args,
+diff --git a/src/tools/cargo/src/cargo/core/compiler/mod.rs b/src/tools/cargo/src/cargo/core/compiler/mod.rs
+index 9399c5042..47d2b9bb4 100644
+--- a/src/tools/cargo/src/cargo/core/compiler/mod.rs
++++ b/src/tools/cargo/src/cargo/core/compiler/mod.rs
+@@ -783,49 +783,9 @@ fn build_base_args(
+         cmd.arg("-C").arg(format!("panic={}", panic));
+     }
+ 
+-    match cx.lto[unit] {
+-        lto::Lto::Run(None) => {
+-            cmd.arg("-C").arg("lto");
+-        }
+-        lto::Lto::Run(Some(s)) => {
+-            cmd.arg("-C").arg(format!("lto={}", s));
+-        }
+-        lto::Lto::Off => {
+-            cmd.arg("-C").arg("lto=off");
+-        }
+-        lto::Lto::ObjectAndBitcode => {} // this is rustc's default
+-        lto::Lto::OnlyBitcode => {
+-            // Note that this compiler flag, like the one below, is just an
+-            // optimization in terms of build time. If we don't pass it then
+-            // both object code and bitcode will show up. This is lagely just
+-            // compat until the feature lands on stable and we can remove the
+-            // conditional branch.
+-            if cx
+-                .bcx
+-                .target_data
+-                .info(CompileKind::Host)
+-                .supports_embed_bitcode
+-                .unwrap()
+-            {
+-                cmd.arg("-Clinker-plugin-lto");
+-            }
+-        }
+-        lto::Lto::OnlyObject => {
+-            if cx
+-                .bcx
+-                .target_data
+-                .info(CompileKind::Host)
+-                .supports_embed_bitcode
+-                .unwrap()
+-            {
+-                cmd.arg("-Cembed-bitcode=no");
+-            }
+-        }
+-    }
++    cmd.args(&lto_args(cx, unit));
+ 
+     if let Some(n) = codegen_units {
+-        // There are some restrictions with LTO and codegen-units, so we
+-        // only add codegen units when LTO is not used.
+         cmd.arg("-C").arg(&format!("codegen-units={}", n));
+     }
+ 
+@@ -952,6 +912,23 @@ fn build_base_args(
+     Ok(())
+ }
+ 
++fn lto_args(cx: &Context<'_, '_>, unit: &Unit) -> Vec<OsString> {
++    let mut result = Vec::new();
++    let mut push = |arg: &str| {
++        result.push(OsString::from("-C"));
++        result.push(OsString::from(arg));
++    };
++    match cx.lto[unit] {
++        lto::Lto::Run(None) => push("lto"),
++        lto::Lto::Run(Some(s)) => push(&format!("lto={}", s)),
++        lto::Lto::Off => push("lto=off"),
++        lto::Lto::ObjectAndBitcode => {} // this is rustc's default
++        lto::Lto::OnlyBitcode => push("linker-plugin-lto"),
++        lto::Lto::OnlyObject => push("embed-bitcode=no"),
++    }
++    result
++}
++
+ fn build_deps_args(
+     cmd: &mut ProcessBuilder,
+     cx: &mut Context<'_, '_>,
+diff --git a/src/tools/cargo/src/cargo/core/profiles.rs b/src/tools/cargo/src/cargo/core/profiles.rs
+index 6a28bd261..ca0c2e417 100644
+--- a/src/tools/cargo/src/cargo/core/profiles.rs
++++ b/src/tools/cargo/src/cargo/core/profiles.rs
+@@ -302,7 +302,7 @@ impl Profiles {
+             };
+ 
+             match mode {
+-                CompileMode::Test | CompileMode::Bench => {
++                CompileMode::Test | CompileMode::Bench | CompileMode::Doctest => {
+                     if release {
+                         (
+                             InternedString::new("bench"),
+@@ -315,10 +315,7 @@ impl Profiles {
+                         )
+                     }
+                 }
+-                CompileMode::Build
+-                | CompileMode::Check { .. }
+-                | CompileMode::Doctest
+-                | CompileMode::RunCustomBuild => {
++                CompileMode::Build | CompileMode::Check { .. } | CompileMode::RunCustomBuild => {
+                     // Note: `RunCustomBuild` doesn't normally use this code path.
+                     // `build_unit_profiles` normally ensures that it selects the
+                     // ancestor's profile. However, `cargo clean -p` can hit this
+-- 
+2.26.2
+

rust.spec

@@ -53,7 +53,7 @@
 
 Name:           rust
 Version:        1.46.0
-Release:        1%{?dist}
+Release:        2%{?dist}
 Summary:        The Rust Programming Language
 License:        (ASL 2.0 or MIT) and (BSD and MIT)
 # ^ written as: (rust itself) and (bundled libraries)
@@ -69,6 +69,8 @@ Source0:        https://static.rust-lang.org/dist/%{rustc_package}.tar.xz
 
 # https://github.com/rust-lang/cargo/pull/8598
 Patch1:         0001-Fix-jobserver_exists-test-on-single-cpu-systems.patch
+# https://github.com/rust-lang/cargo/pull/8657 (backported)
+Patch2:         0002-Fix-LTO-with-doctests.patch
 
 ### RHEL-specific patches below ###
 
@@ -409,6 +411,7 @@ test -f '%{local_rust_root}/bin/rustc'
 %setup -q -n %{rustc_package}
 
 %patch1 -p1 -d src/tools/cargo
+%patch2 -p1
 
 %if %with disabled_libssh2
 %patch100 -p1
@@ -744,6 +747,9 @@ rm -f %{buildroot}%{rustlibdir}/etc/lldb_*.py*
 
 
 %changelog
+* Fri Aug 28 2020 Fabio Valentini <decathorpe@gmail.com> - 1.46.0-2
+- Fix LTO with doctests (backported cargo PR#8657).
+
 * Thu Aug 27 2020 Josh Stone <jistone@redhat.com> - 1.46.0-1
 - Update to 1.46.0.