trans: Clean up handling the LLVM data layout

Turns out for OSX our data layout was subtly wrong and the LLVM update must have
exposed this. Instead of fixing this I've removed all data layouts from the
compiler to just use the defaults that LLVM provides for all targets. All data
layouts (and a number of dead modules) are removed from the compiler here.
Custom target specifications can still provide a custom data layout, but it is
now an optional key as the default will be used if one isn't specified.

Author: alexcrichton

src/librustc/lib.rs

@@ -99,14 +99,8 @@ pub mod diagnostics;
 
 pub mod back {
     pub use rustc_back::abi;
-    pub use rustc_back::arm;
-    pub use rustc_back::mips;
-    pub use rustc_back::mipsel;
     pub use rustc_back::rpath;
     pub use rustc_back::svh;
-    pub use rustc_back::target_strs;
-    pub use rustc_back::x86;
-    pub use rustc_back::x86_64;
 }
 
 pub mod ast_map;

src/librustc_back/arm.rs

@@ -52,13 +52,7 @@ extern crate rustc_llvm;
 
 pub mod abi;
 pub mod tempdir;
-pub mod arm;
-pub mod mips;
-pub mod mipsel;
 pub mod rpath;
 pub mod sha2;
 pub mod svh;
-pub mod target_strs;
-pub mod x86;
-pub mod x86_64;
 pub mod target;

src/librustc_back/lib.rs

@@ -13,10 +13,6 @@ use super::apple_ios_base::{opts, Arch};
 
 pub fn target() -> Target {
     Target {
-        // reference layout: e-m:o-i64:64-i128:128-n32:64-S128
-        data_layout: "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-\
-                      i128:128-f32:32:32-f64:64:64-v64:64:64-v128:128:128-\
-                      a:0:64-n32:64-S128".to_string(),
         llvm_target: "arm64-apple-ios".to_string(),
         target_endian: "little".to_string(),
         target_pointer_width: "64".to_string(),

src/librustc_back/mips.rs

@@ -12,9 +12,6 @@ use target::Target;
 
 pub fn target() -> Target {
     Target {
-        data_layout: "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-\
-                      f32:32:32-f64:64:64-v64:64:64-v128:128:128-a:0:64-\
-                      n32:64-S128".to_string(),
         llvm_target: "aarch64-linux-android".to_string(),
         target_endian: "little".to_string(),
         target_pointer_width: "64".to_string(),

src/librustc_back/mipsel.rs

@@ -13,9 +13,6 @@ use target::Target;
 pub fn target() -> Target {
     let base = super::linux_base::opts();
     Target {
-        data_layout: "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-\
-                      f32:32:32-f64:64:64-v64:64:64-v128:128:128-a:0:64-\
-                      n32:64-S128".to_string(),
         llvm_target: "aarch64-unknown-linux-gnu".to_string(),
         target_endian: "little".to_string(),
         target_pointer_width: "64".to_string(),

src/librustc_back/target/aarch64_apple_ios.rs

@@ -15,9 +15,6 @@ pub fn target() -> Target {
     base.features = "+v7".to_string();
 
     Target {
-        data_layout: "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-\
-                      f32:32:32-f64:64:64-v64:64:64-v128:64:128-a:0:64-\
-                      n32".to_string(),
         llvm_target: "arm-linux-androideabi".to_string(),
         target_endian: "little".to_string(),
         target_pointer_width: "32".to_string(),

src/librustc_back/target/aarch64_linux_android.rs

@@ -13,11 +13,6 @@ use target::{Target, TargetOptions};
 pub fn target() -> Target {
     let base = super::linux_base::opts();
     Target {
-        data_layout: "e-p:32:32:32\
-                      -i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64\
-                      -f32:32:32-f64:64:64\
-                      -v64:64:64-v128:64:128\
-                      -a:0:64-n32".to_string(),
         llvm_target: "arm-unknown-linux-gnueabi".to_string(),
         target_endian: "little".to_string(),
         target_pointer_width: "32".to_string(),