dev-lang/rust: fix building 1.35.0 with internal llvm

Closes: https://bugs.gentoo.org/686656
X-Upstream-Issue: https://github.com/rust-lang/rust/issues/61206
Package-Manager: Portage-2.3.66, Repoman-2.3.12
Signed-off-by: Georgy Yakovlev <gyakovlev@gentoo.org>

2 files changed, 118 insertions, 0 deletions

diff --git a/dev-lang/rust/files/1.35.0-revert-commits-triggering-multiple-llvm-rebuilds.patch b/dev-lang/rust/files/1.35.0-revert-commits-triggering-multiple-llvm-rebuilds.patch
new file mode 100644
index 000000000000..1c6c8ca404d9
--- /dev/null
+++ b/dev-lang/rust/files/1.35.0-revert-commits-triggering-multiple-llvm-rebuilds.patch
@@ -0,0 +1,117 @@
+From d6bd0a479ceaf6abdd696c3b955a56f66275c562 Mon Sep 17 00:00:00 2001
+From: Georgy Yakovlev <gyakovlev@gentoo.org>
+Date: Sat, 25 May 2019 22:21:16 -0700
+Subject: [PATCH] revert commits triggering multiple llvm rebuilds
+
+this reverts the following commits
+https://github.com/rust-lang/rust/commit/105692c3ad281c63bf0f75a26a66bb9cff5b4553
+https://github.com/rust-lang/rust/commit/975ba58f42b34ff07cd7c2bd73350daed2057186
+https://github.com/rust-lang/rust/commit/e1daa36ba7df88788c2684bbe5ff6eb37f1cda69
+---
+ src/bootstrap/llvm-rebuild-trigger |  4 +++
+ src/bootstrap/native.rs            | 46 +++++++++++++-----------------
+ 2 files changed, 24 insertions(+), 26 deletions(-)
+ create mode 100644 src/bootstrap/llvm-rebuild-trigger
+
+diff --git a/src/bootstrap/llvm-rebuild-trigger b/src/bootstrap/llvm-rebuild-trigger
+new file mode 100644
+index 0000000000..0f18c6a4ac
+--- /dev/null
++++ b/src/rustllvm/llvm-rebuild-trigger
+@@ -0,0 +1,4 @@
++# If this file is modified, then llvm will be (optionally) cleaned and then rebuilt.
++# The actual contents of this file do not matter, but to trigger a change on the
++# build bots then the contents should be changed so git updates the mtime.
++2019-03-18
+diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
+index fde40b0d1b..3babbc9e10 100644
+--- a/src/bootstrap/native.rs
++++ b/src/bootstrap/native.rs
+@@ -67,40 +67,30 @@ impl Step for Llvm {
+             }
+         }
+ 
+-        let (llvm_info, root, out_dir, llvm_config_ret_dir) = if emscripten {
+-            let info = &builder.emscripten_llvm_info;
++        let rebuild_trigger = builder.src.join("src/rustllvm/llvm-rebuild-trigger");
++        let rebuild_trigger_contents = t!(fs::read_to_string(&rebuild_trigger));
++
++        let (out_dir, llvm_config_ret_dir) = if emscripten {
+             let dir = builder.emscripten_llvm_out(target);
+             let config_dir = dir.join("bin");
+-            (info, "src/llvm-emscripten", dir, config_dir)
++            (dir, config_dir)
+         } else {
+-            let info = &builder.in_tree_llvm_info;
+             let mut dir = builder.llvm_out(builder.config.build);
+             if !builder.config.build.contains("msvc") || builder.config.ninja {
+                 dir.push("build");
+             }
+-            (info, "src/llvm-project/llvm", builder.llvm_out(target), dir.join("bin"))
++            (builder.llvm_out(target), dir.join("bin"))
+         };
+-
+-        if !llvm_info.is_git() {
+-            println!(
+-                "git could not determine the LLVM submodule commit hash. \
+-                Assuming that an LLVM build is necessary.",
+-            );
+-        }
+-
++        let done_stamp = out_dir.join("llvm-finished-building");
+         let build_llvm_config = llvm_config_ret_dir
+             .join(exe("llvm-config", &*builder.config.build));
+-        let done_stamp = out_dir.join("llvm-finished-building");
+-
+-        if let Some(llvm_commit) = llvm_info.sha() {
+-            if done_stamp.exists() {
+-                let done_contents = t!(fs::read(&done_stamp));
++        if done_stamp.exists() {
++            let done_contents = t!(fs::read_to_string(&done_stamp));
+ 
+-                // If LLVM was already built previously and the submodule's commit didn't change
+-                // from the previous build, then no action is required.
+-                if done_contents == llvm_commit.as_bytes() {
+-                    return build_llvm_config
+-                }
++            // If LLVM was already built previously and contents of the rebuild-trigger file
++            // didn't change from the previous build, then no action is required.
++            if done_contents == rebuild_trigger_contents {
++                return build_llvm_config
+             }
+         }
+ 
+@@ -111,6 +101,7 @@ impl Step for Llvm {
+         t!(fs::create_dir_all(&out_dir));
+ 
+         // http://llvm.org/docs/CMake.html
++        let root = if self.emscripten { "src/llvm-emscripten" } else { "src/llvm-project/llvm" };
+         let mut cfg = cmake::Config::new(builder.src.join(root));
+ 
+         let profile = match (builder.config.llvm_optimize, builder.config.llvm_release_debuginfo) {
+@@ -251,6 +242,11 @@ impl Step for Llvm {
+                 channel::CFG_RELEASE_NUM,
+                 builder.config.channel,
+             );
++            let llvm_info = if self.emscripten {
++                &builder.emscripten_llvm_info
++            } else {
++                &builder.in_tree_llvm_info
++            };
+             if let Some(sha) = llvm_info.sha_short() {
+                 default_suffix.push_str("-");
+                 default_suffix.push_str(sha);
+@@ -283,9 +279,7 @@ impl Step for Llvm {
+ 
+         cfg.build();
+ 
+-        if let Some(llvm_commit) = llvm_info.sha() {
+-            t!(fs::write(&done_stamp, llvm_commit));
+-        }
++        t!(fs::write(&done_stamp, &rebuild_trigger_contents));
+ 
+         build_llvm_config
+     }
+-- 
+2.21.0
+
diff --git a/dev-lang/rust/rust-1.35.0.ebuild b/dev-lang/rust/rust-1.35.0.ebuild
index 801838bb704f..b5725b81510c 100644
--- a/dev-lang/rust/rust-1.35.0.ebuild
+++ b/dev-lang/rust/rust-1.35.0.ebuild
@@ -89,6 +89,7 @@ REQUIRED_USE="|| ( ${ALL_LLVM_TARGETS[*]} )
 
 PATCHES=(
 	"${FILESDIR}"/0001-llvm-cmake-Add-additional-headers-only-if-they-exist.patch
+	"${FILESDIR}"/1.35.0-revert-commits-triggering-multiple-llvm-rebuilds.patch
 )
 
 S="${WORKDIR}/${MY_P}-src"