Rollup merge of #56944 - alexcrichton:less-thin2, r=michaelwoerister

bootstrap: Link LLVM as a dylib with ThinLTO

When building a distributed compiler on Linux where we use ThinLTO to
create the LLVM shared object this commit switches the compiler to
dynamically linking that LLVM artifact instead of statically linking to
LLVM. The primary goal here is to reduce CI compile times, avoiding two+
ThinLTO builds of all of LLVM. By linking dynamically to LLVM we'll
reuse the one ThinLTO step done by LLVM's build itself.

Lots of discussion about this change can be found [here] and down. A
perf run will show whether this is worth it or not!

[here]: https://github.com/rust-lang/rust/pull/53245#issuecomment-417015334

5 files changed, 0 insertions, 181 deletions

diff --git a/src/test/run-make-fulldeps/llvm-pass/Makefile b/src/test/run-make-fulldeps/llvm-pass/Makefile
deleted file mode 100644
index 8a18aadf36a..00000000000
--- a/src/test/run-make-fulldeps/llvm-pass/Makefile
+++ /dev/null
@@ -1,28 +0,0 @@
--include ../tools.mk
-
-ifeq ($(UNAME),Darwin)
-PLUGIN_FLAGS := -C link-args=-Wl,-undefined,dynamic_lookup
-endif
-
-ifeq ($(findstring stage1,$(RUST_BUILD_STAGE)),stage1)
-# ignore stage1
-all:
-
-else
-# Windows doesn't correctly handle include statements with escaping paths,
-# so this test will not get run on Windows.
-ifdef IS_WINDOWS
-all:
-else
-all: $(call NATIVE_STATICLIB,llvm-function-pass) $(call NATIVE_STATICLIB,llvm-module-pass)
-	$(RUSTC) plugin.rs -C prefer-dynamic $(PLUGIN_FLAGS)
-	$(RUSTC) main.rs
-
-$(TMPDIR)/libllvm-function-pass.o:
-	$(CXX) $(CFLAGS) $(LLVM_CXXFLAGS) -c llvm-function-pass.so.cc -o $(TMPDIR)/libllvm-function-pass.o
-
-$(TMPDIR)/libllvm-module-pass.o:
-	$(CXX) $(CFLAGS) $(LLVM_CXXFLAGS) -c llvm-module-pass.so.cc -o $(TMPDIR)/libllvm-module-pass.o
-endif
-
-endif
diff --git a/src/test/run-make-fulldeps/llvm-pass/llvm-function-pass.so.cc b/src/test/run-make-fulldeps/llvm-pass/llvm-function-pass.so.cc
deleted file mode 100644
index c0a17d920cf..00000000000
--- a/src/test/run-make-fulldeps/llvm-pass/llvm-function-pass.so.cc
+++ /dev/null
@@ -1,56 +0,0 @@
-// Copyright 2016 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.
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-#include "llvm/Pass.h"
-#include "llvm/IR/Function.h"
-
-using namespace llvm;
-
-namespace {
-
-  class TestLLVMPass : public FunctionPass {
-
-  public:
-
-    static char ID;
-    TestLLVMPass() : FunctionPass(ID) { }
-
-    bool runOnFunction(Function &F) override;
-
-    StringRef getPassName() const override {
-      return "Some LLVM pass";
-    }
-
-  };
-
-}
-
-bool TestLLVMPass::runOnFunction(Function &F) {
-  // A couple examples of operations that previously caused segmentation faults
-  // https://github.com/rust-lang/rust/issues/31067
-
-  for (auto N = F.begin(); N != F.end(); ++N) {
-    /* code */
-  }
-
-  LLVMContext &C = F.getContext();
-  IntegerType *Int8Ty  = IntegerType::getInt8Ty(C);
-  PointerType::get(Int8Ty, 0);
-  return true;
-}
-
-char TestLLVMPass::ID = 0;
-
-static RegisterPass<TestLLVMPass> RegisterAFLPass(
-  "some-llvm-function-pass", "Some LLVM pass");
diff --git a/src/test/run-make-fulldeps/llvm-pass/llvm-module-pass.so.cc b/src/test/run-make-fulldeps/llvm-pass/llvm-module-pass.so.cc
deleted file mode 100644
index 70051681ab0..00000000000
--- a/src/test/run-make-fulldeps/llvm-pass/llvm-module-pass.so.cc
+++ /dev/null
@@ -1,55 +0,0 @@
-// Copyright 2016 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.
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-#include "llvm/IR/Module.h"
-
-using namespace llvm;
-
-namespace {
-
-  class TestLLVMPass : public ModulePass {
-
-  public:
-
-    static char ID;
-    TestLLVMPass() : ModulePass(ID) { }
-
-    bool runOnModule(Module &M) override;
-
-    StringRef getPassName() const override {
-      return "Some LLVM pass";
-    }
-
-  };
-
-}
-
-bool TestLLVMPass::runOnModule(Module &M) {
-  // A couple examples of operations that previously caused segmentation faults
-  // https://github.com/rust-lang/rust/issues/31067
-
-  for (auto F = M.begin(); F != M.end(); ++F) {
-    /* code */
-  }
-
-  LLVMContext &C = M.getContext();
-  IntegerType *Int8Ty  = IntegerType::getInt8Ty(C);
-  PointerType::get(Int8Ty, 0);
-  return true;
-}
-
-char TestLLVMPass::ID = 0;
-
-static RegisterPass<TestLLVMPass> RegisterAFLPass(
-  "some-llvm-module-pass", "Some LLVM pass");
diff --git a/src/test/run-make-fulldeps/llvm-pass/main.rs b/src/test/run-make-fulldeps/llvm-pass/main.rs
deleted file mode 100644
index 5b5ab94bcef..00000000000
--- a/src/test/run-make-fulldeps/llvm-pass/main.rs
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright 2016 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.
-
-#![feature(plugin)]
-#![plugin(some_plugin)]
-
-fn main() {}
diff --git a/src/test/run-make-fulldeps/llvm-pass/plugin.rs b/src/test/run-make-fulldeps/llvm-pass/plugin.rs
deleted file mode 100644
index f77b2fca857..00000000000
--- a/src/test/run-make-fulldeps/llvm-pass/plugin.rs
+++ /dev/null
@@ -1,28 +0,0 @@
-// Copyright 2016 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.
-
-#![feature(plugin_registrar, rustc_private)]
-#![crate_type = "dylib"]
-#![crate_name = "some_plugin"]
-
-extern crate rustc;
-extern crate rustc_plugin;
-
-#[link(name = "llvm-function-pass", kind = "static")]
-#[link(name = "llvm-module-pass", kind = "static")]
-extern {}
-
-use rustc_plugin::registry::Registry;
-
-#[plugin_registrar]
-pub fn plugin_registrar(reg: &mut Registry) {
-    reg.register_llvm_pass("some-llvm-function-pass");
-    reg.register_llvm_pass("some-llvm-module-pass");
-}