[RISCV] Enable CI.

config.toml.example

@@ -61,7 +61,7 @@
 # the same format as above, but since these targets are experimental, they are
 # not built by default and the experimental Rust compilation targets that depend
 # on them will not work unless the user opts in to building them. By default the
-# `WebAssembly` target is enabled when compiling LLVM from scratch.
+# `WebAssembly` and `RISCV` targets are enabled when compiling LLVM from scratch.
 #experimental-targets = "WebAssembly;RISCV"
 
 # Cap the number of parallel linker invocations when compiling LLVM.

src/bootstrap/config.rs

@@ -507,7 +507,7 @@ impl Config {
             set(&mut config.llvm_link_shared, llvm.link_shared);
             config.llvm_targets = llvm.targets.clone();
             config.llvm_experimental_targets = llvm.experimental_targets.clone()
-                .unwrap_or("WebAssembly".to_string());
+                .unwrap_or("WebAssembly;RISCV".to_string());
             config.llvm_link_jobs = llvm.link_jobs;
             config.llvm_clang_cl = llvm.clang_cl.clone();
         }

src/ci/docker/dist-various-1/Dockerfile

@@ -102,6 +102,7 @@ ENV TARGETS=$TARGETS,thumbv6m-none-eabi
 ENV TARGETS=$TARGETS,thumbv7m-none-eabi
 ENV TARGETS=$TARGETS,thumbv7em-none-eabi
 ENV TARGETS=$TARGETS,thumbv7em-none-eabihf
+ENV TARGETS=$TARGETS,riscv32imac-unknown-none-elf
 
 ENV CC_mipsel_unknown_linux_musl=mipsel-openwrt-linux-gcc \
     CC_mips_unknown_linux_musl=mips-openwrt-linux-gcc \

src/tools/build-manifest/src/main.rs

@@ -89,6 +89,7 @@ static TARGETS: &'static [&'static str] = &[
     "powerpc64-unknown-linux-gnu",
     "powerpc64le-unknown-linux-gnu",
     "powerpc64le-unknown-linux-musl",
+    "riscv32imac-unknown-none-elf",
     "s390x-unknown-linux-gnu",
     "sparc-unknown-linux-gnu",
     "sparc64-unknown-linux-gnu",