Auto merge of #58408 - alexcrichton:update-llvm, r=michaelwoerister

rustc: Update LLVM, remove dead wasm code

This commit updates the LLVM branch to the rebased version of the
upstream release/8.x branch. This includes a wasm patch which means that
the `rewrite_imports` pass in rustc is no longer needed (yay!) and we
can instead rely on `wasm-import-module`, an attribute we're already
emitting, to take care of all the work.

2 files changed, 7 insertions, 0 deletions

diff --git a/src/bootstrap/config.rs b/src/bootstrap/config.rs
index 7d3e584f1a6..d20958854ed 100644
--- a/src/bootstrap/config.rs
+++ b/src/bootstrap/config.rs
@@ -78,6 +78,7 @@ pub struct Config {
     pub llvm_link_jobs: Option<u32>,
     pub llvm_version_suffix: Option<String>,
     pub llvm_use_linker: Option<String>,
+    pub llvm_allow_old_toolchain: Option<bool>,
 
     pub lld_enabled: bool,
     pub lldb_enabled: bool,
@@ -263,6 +264,7 @@ struct Llvm {
     ldflags: Option<String>,
     use_libcxx: Option<bool>,
     use_linker: Option<String>,
+    allow_old_toolchain: Option<bool>,
 }
 
 #[derive(Deserialize, Default, Clone)]
@@ -530,6 +532,7 @@ impl Config {
             config.llvm_ldflags = llvm.ldflags.clone();
             set(&mut config.llvm_use_libcxx, llvm.use_libcxx);
             config.llvm_use_linker = llvm.use_linker.clone();
+            config.llvm_allow_old_toolchain = llvm.allow_old_toolchain.clone();
         }
 
         if let Some(ref rust) = toml.rust {
diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index 192b1cd1fbb..d78670cfe51 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -238,6 +238,10 @@ impl Step for Llvm {
             cfg.define("LLVM_USE_LINKER", linker);
         }
 
+        if let Some(true) = builder.config.llvm_allow_old_toolchain {
+            cfg.define("LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN", "YES");
+        }
+
         if let Some(ref python) = builder.config.python {
             cfg.define("PYTHON_EXECUTABLE", python);
         }