Rollup merge of #41524 - michaelwu:basic-hexagon, r=alexcrichton

Add Hexagon support

This requires an updated LLVM with https://reviews.llvm.org/D31999 and https://reviews.llvm.org/D32000 to build libcore.

A basic hello world builds and runs successfully on the hexagon simulator. libcore is fine with LLVM fixes, but libstd requires a lot more work since there's a custom rtos running on most hexagon cores. Running Linux sounds possible though, so maybe getting linux + musl going would be easier.

Here's the target file I've been using for testing
```
{
    "arch": "hexagon",
    "llvm-target": "hexagon-unknown-elf",
    "os": "none",
    "target-endian": "little",
    "target-pointer-width": "32",

    "data-layout": "e-m:e-p:32:32:32-a:0-n16:32-i64:64:64-i32:32:32-i16:16:16-i1:8:8-f32:32:32-f64:64:64-v32:32:32-v64:64:64-v512:512:512-v1024:1024:1024-v2048:2048:2048",
    "linker": "hexagon-clang",
    "linker-flavor": "gcc",
    "executables": true,
    "cpu": "hexagonv60"
}
```

Author: Ariel Ben-Yehuda

src/bootstrap/config.toml.example

@@ -51,7 +51,7 @@
 # support. You'll need to write a target specification at least, and most
 # likely, teach rustc about the C ABI of the target. Get in touch with the
 # Rust team and file an issue if you need assistance in porting!
-#targets = "X86;ARM;AArch64;Mips;PowerPC;SystemZ;JSBackend;MSP430;Sparc;NVPTX"
+#targets = "X86;ARM;AArch64;Mips;PowerPC;SystemZ;JSBackend;MSP430;Sparc;NVPTX;Hexagon"
 
 # Cap the number of parallel linker invocations when compiling LLVM.
 # This can be useful when building LLVM with debug info, which significantly

src/bootstrap/native.rs

@@ -81,7 +81,7 @@ pub fn llvm(build: &Build, target: &str) {
     // NOTE: remember to also update `config.toml.example` when changing the defaults!
     let llvm_targets = match build.config.llvm_targets {
         Some(ref s) => s,
-        None => "X86;ARM;AArch64;Mips;PowerPC;SystemZ;JSBackend;MSP430;Sparc;NVPTX",
+        None => "X86;ARM;AArch64;Mips;PowerPC;SystemZ;JSBackend;MSP430;Sparc;NVPTX;Hexagon",
     };
 
     let assertions = if build.config.llvm_assertions {"ON"} else {"OFF"};

src/librustc_llvm/build.rs

@@ -17,30 +17,24 @@ use std::path::{PathBuf, Path};
 
 use build_helper::output;
 
-fn detect_llvm_link(llvm_config: &Path) -> (&'static str, Option<&'static str>) {
-    let mut version_cmd = Command::new(llvm_config);
-    version_cmd.arg("--version");
-    let version_output = output(&mut version_cmd);
-    let mut parts = version_output.split('.').take(2)
-        .filter_map(|s| s.parse::<u32>().ok());
-    if let (Some(major), Some(minor)) = (parts.next(), parts.next()) {
-        if major > 3 || (major == 3 && minor >= 9) {
-            // Force the link mode we want, preferring static by default, but
-            // possibly overridden by `configure --enable-llvm-link-shared`.
-            if env::var_os("LLVM_LINK_SHARED").is_some() {
-                return ("dylib", Some("--link-shared"));
-            } else {
-                return ("static", Some("--link-static"));
-            }
-        } else if major == 3 && minor == 8 {
-            // Find out LLVM's default linking mode.
-            let mut mode_cmd = Command::new(llvm_config);
-            mode_cmd.arg("--shared-mode");
-            if output(&mut mode_cmd).trim() == "shared" {
-                return ("dylib", None);
-            } else {
-                return ("static", None);
-            }
+fn detect_llvm_link(major: u32, minor: u32, llvm_config: &Path)
+    -> (&'static str, Option<&'static str>) {
+    if major > 3 || (major == 3 && minor >= 9) {
+        // Force the link mode we want, preferring static by default, but
+        // possibly overridden by `configure --enable-llvm-link-shared`.
+        if env::var_os("LLVM_LINK_SHARED").is_some() {
+            return ("dylib", Some("--link-shared"));
+        } else {
+            return ("static", Some("--link-static"));
+        }
+    } else if major == 3 && minor == 8 {
+        // Find out LLVM's default linking mode.
+        let mut mode_cmd = Command::new(llvm_config);
+        mode_cmd.arg("--shared-mode");
+        if output(&mut mode_cmd).trim() == "shared" {
+            return ("dylib", None);
+        } else {
+            return ("static", None);
         }
     }
     ("static", None)
@@ -92,9 +86,25 @@ fn main() {
     let host = env::var("HOST").expect("HOST was not set");
     let is_crossed = target != host;
 
-    let optional_components =
-        ["x86", "arm", "aarch64", "mips", "powerpc", "pnacl", "systemz", "jsbackend", "msp430",
-         "sparc", "nvptx"];
+    let mut optional_components =
+        vec!["x86", "arm", "aarch64", "mips", "powerpc", "pnacl",
+             "systemz", "jsbackend", "msp430", "sparc", "nvptx"];
+
+    let mut version_cmd = Command::new(&llvm_config);
+    version_cmd.arg("--version");
+    let version_output = output(&mut version_cmd);
+    let mut parts = version_output.split('.').take(2)
+        .filter_map(|s| s.parse::<u32>().ok());
+    let (major, minor) =
+        if let (Some(major), Some(minor)) = (parts.next(), parts.next()) {
+            (major, minor)
+        } else {
+            (3, 7)
+        };
+
+    if major > 3 {
+        optional_components.push("hexagon");
+    }
 
     // FIXME: surely we don't need all these components, right? Stuff like mcjit
     //        or interpreter the compiler itself never uses.
@@ -158,7 +168,7 @@ fn main() {
        .cpp_link_stdlib(None) // we handle this below
        .compile("librustllvm.a");
 
-    let (llvm_kind, llvm_link_arg) = detect_llvm_link(&llvm_config);
+    let (llvm_kind, llvm_link_arg) = detect_llvm_link(major, minor, &llvm_config);
 
     // Link in all LLVM libraries, if we're uwring the "wrong" llvm-config then
     // we don't pick up system libs because unfortunately they're for the host

src/librustc_llvm/lib.rs

@@ -382,6 +382,12 @@ pub fn initialize_available_targets() {
                  LLVMInitializeNVPTXTarget,
                  LLVMInitializeNVPTXTargetMC,
                  LLVMInitializeNVPTXAsmPrinter);
+    init_target!(llvm_component = "hexagon",
+                 LLVMInitializeHexagonTargetInfo,
+                 LLVMInitializeHexagonTarget,
+                 LLVMInitializeHexagonTargetMC,
+                 LLVMInitializeHexagonAsmPrinter,
+                 LLVMInitializeHexagonAsmParser);
 }
 
 pub fn last_error() -> Option<String> {

src/librustc_trans/abi.rs

@@ -29,6 +29,7 @@ use cabi_sparc;
 use cabi_sparc64;
 use cabi_nvptx;
 use cabi_nvptx64;
+use cabi_hexagon;
 use machine::llalign_of_min;
 use type_::Type;
 use type_of;
@@ -896,6 +897,7 @@ impl<'a, 'tcx> FnType<'tcx> {
             "sparc64" => cabi_sparc64::compute_abi_info(ccx, self),
             "nvptx" => cabi_nvptx::compute_abi_info(ccx, self),
             "nvptx64" => cabi_nvptx64::compute_abi_info(ccx, self),
+            "hexagon" => cabi_hexagon::compute_abi_info(ccx, self),
             a => ccx.sess().fatal(&format!("unrecognized arch \"{}\" in target specification", a))
         }
 

src/librustc_trans/cabi_hexagon.rs

@@ -0,0 +1,43 @@
+// Copyright 2012-2013 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.
+
+#![allow(non_upper_case_globals)]
+
+use abi::{FnType, ArgType, LayoutExt};
+use context::CrateContext;
+
+fn classify_ret_ty<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ret: &mut ArgType<'tcx>) {
+    if ret.layout.is_aggregate() && ret.layout.size(ccx).bits() > 64 {
+        ret.make_indirect(ccx);
+    } else {
+        ret.extend_integer_width_to(32);
+    }
+}
+
+fn classify_arg_ty<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, arg: &mut ArgType<'tcx>) {
+    if arg.layout.is_aggregate() && arg.layout.size(ccx).bits() > 64 {
+        arg.make_indirect(ccx);
+    } else {
+        arg.extend_integer_width_to(32);
+    }
+}
+
+pub fn compute_abi_info<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, fty: &mut FnType<'tcx>) {
+    if !fty.ret.is_ignore() {
+        classify_ret_ty(ccx, &mut fty.ret);
+    }
+
+    for arg in &mut fty.args {
+        if arg.is_ignore() {
+            continue;
+        }
+        classify_arg_ty(ccx, arg);
+    }
+}

src/librustc_trans/lib.rs

@@ -97,6 +97,7 @@ mod builder;
 mod cabi_aarch64;
 mod cabi_arm;
 mod cabi_asmjs;
+mod cabi_hexagon;
 mod cabi_mips;
 mod cabi_mips64;
 mod cabi_msp430;

src/llvm

@@ -147,6 +147,12 @@ extern "C" void LLVMRustAddPass(LLVMPassManagerRef PMR, LLVMPassRef RustPass) {
 #define SUBTARGET_SPARC
 #endif
 
+#ifdef LLVM_COMPONENT_HEXAGON
+#define SUBTARGET_HEXAGON SUBTARGET(Hexagon)
+#else
+#define SUBTARGET_HEXAGON
+#endif
+
 #define GEN_SUBTARGETS                                                         \
   SUBTARGET_X86                                                                \
   SUBTARGET_ARM                                                                \
@@ -155,7 +161,8 @@ extern "C" void LLVMRustAddPass(LLVMPassManagerRef PMR, LLVMPassRef RustPass) {
   SUBTARGET_PPC                                                                \
   SUBTARGET_SYSTEMZ                                                            \
   SUBTARGET_MSP430                                                             \
-  SUBTARGET_SPARC
+  SUBTARGET_SPARC                                                              \
+  SUBTARGET_HEXAGON
 
 #define SUBTARGET(x)                                                           \
   namespace llvm {                                                             \

src/rustllvm/PassWrapper.cpp

@@ -1,4 +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.
-2017-03-23
+2017-04-25