remove build dependency on arm-none-eabi-gcc

by shipping pre-assembled object files. This is the same approach as the one
used in rust-embedded/cortex-m#95

40 files changed, 279 insertions, 218 deletions

diff --git a/.gitignore b/.gitignore
index 1839608..9c3fcb4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,7 @@
 *.rs.bk
 .#*
 Cargo.lock
+bin/*.after
+bin/*.before
+bin/*.o
 target
diff --git a/.travis.yml b/.travis.yml
index 3086616..846370a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,76 +3,46 @@ language: rust
 matrix:
   include:
     - env: TARGET=x86_64-unknown-linux-gnu
+      rust: stable
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv6m-none-eabi
-      rust: beta
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
+      rust: stable
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv7m-none-eabi
-      rust: beta
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
+      rust: stable
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv7em-none-eabi
-      rust: beta
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
+      rust: stable
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv7em-none-eabihf
-      rust: beta
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
+      rust: stable
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv6m-none-eabi
       rust: nightly
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv7m-none-eabi
       rust: nightly
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv7em-none-eabi
       rust: nightly
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv7em-none-eabihf
       rust: nightly
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
 before_install: set -e
 
 install:
   - bash ci/install.sh
+  - export PATH="$PATH:$PWD/gcc/bin"
 
 script:
   - bash ci/script.sh
diff --git a/Cargo.toml b/Cargo.toml
index 9bd3c92..32d0342 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,9 +9,6 @@ name = "cortex-m"
 repository = "https://github.com/japaric/cortex-m"
 version = "0.5.4"
 
-[build-dependencies]
-cc = "1.0.10"
-
 [dependencies]
 aligned = "0.2.0"
 bare-metal = "0.2.0"
diff --git a/asm-cm7-r0p1.s b/asm-cm7-r0p1.s
new file mode 100644
index 0000000..a9ebf4a
--- /dev/null
+++ b/asm-cm7-r0p1.s
@@ -0,0 +1,27 @@
+  .section .text.__basepri_max_cm7_r0p1
+  .global __basepri_max_cm7_r0p1
+  .syntax unified
+  .thumb_func
+__basepri_max_cm7_r0p1:
+  mrs r1, PRIMASK
+  cpsid i
+  tst.w r1, #1
+  msr BASEPRI_MAX, r0
+  it ne
+  bxne lr
+  cpsie i
+  bx lr
+
+  .section .text.__basepri_w_cm7_r0p1
+  .global __basepri_w_cm7_r0p1
+  .syntax unified
+  .thumb_func
+__basepri_w_cm7_r0p1:
+  mrs r1, PRIMASK
+  cpsid i
+  tst.w r1, #1
+  msr BASEPRI, r0
+  it ne
+  bxne lr
+  cpsie i
+  bx lr
diff --git a/asm-v7.s b/asm-v7.s
new file mode 100644
index 0000000..c4c6dfb
--- /dev/null
+++ b/asm-v7.s
@@ -0,0 +1,27 @@
+  .section .text.__basepri_max
+  .global __basepri_max
+  .thumb_func
+__basepri_max:
+  msr BASEPRI_MAX, r0
+  bx lr
+
+  .section .text.__basepri_r
+  .global __basepri_r
+  .thumb_func
+__basepri_r:
+  mrs r0, BASEPRI
+  bx lr
+
+  .section .text.__basepri_w
+  .global __basepri_w
+  .thumb_func
+__basepri_w:
+  msr BASEPRI, r0
+  bx lr
+
+  .section .text.__faultmask
+  .global __faultmask
+  .thumb_func
+__faultmask:
+  mrs r0, FAULTMASK
+  bx lr
diff --git a/asm.s b/asm.s
new file mode 100644
index 0000000..bf2fd46
--- /dev/null
+++ b/asm.s
@@ -0,0 +1,120 @@
+  .section .text.__bkpt
+  .global __bkpt
+  .thumb_func
+__bkpt:
+  bkpt
+  bx lr
+
+  .section .text.__control
+  .global __control
+  .thumb_func
+__control:
+  mrs r0, CONTROL
+  bx lr
+
+  .section .text.__cpsid
+  .global __cpsid
+  .thumb_func
+__cpsid:
+  cpsid i
+  bx lr
+
+  .section .text.__cpsie
+  .global __cpsie
+  .thumb_func
+__cpsie:
+  cpsie i
+  bx lr
+
+  .section .text.__delay
+  .global __delay
+  .syntax unified
+  .thumb_func
+__delay:
+  nop
+  subs r0, #1
+  bne __delay
+  bx lr
+
+  .section .text.__dmb
+  .global __dmb
+  .thumb_func
+__dmb:
+  dmb 0xF
+  bx lr
+
+  .section .text.__dsb
+  .global __dsb
+  .thumb_func
+__dsb:
+  dsb 0xF
+  bx lr
+
+  .section .text.__isb
+  .global __isb
+  .thumb_func
+__isb:
+  isb 0xF
+  bx lr
+
+  .section .text.__msp_r
+  .global __msp_r
+  .thumb_func
+__msp_r:
+  mrs r0, MSP
+  bx lr
+
+  .section .text.__msp_w
+  .global __msp_w
+  .thumb_func
+__msp_w:
+  msr MSP, r0
+  bx lr
+
+  .section .text.__nop
+  .global __nop
+  .thumb_func
+__nop:
+  bx lr
+
+  .section .text.__primask
+  .global __primask
+  .thumb_func
+__primask:
+  mrs r0, PRIMASK
+  bx lr
+
+  .section .text.__psp_r
+  .global __psp_r
+  .thumb_func
+__psp_r:
+  mrs r0, PSP
+  bx lr
+
+  .section .text.__psp_w
+  .global __psp_w
+  .thumb_func
+__psp_w:
+  msr PSP, r0
+  bx lr
+
+  .section .text.__sev
+  .global __sev
+  .thumb_func
+__sev:
+  sev
+  bx lr
+
+  .section .text.__wfe
+  .global __wfe
+  .thumb_func
+__wfe:
+  wfe
+  bx lr
+
+  .section .text.__wfi
+  .global __wfi
+  .thumb_func
+__wfi:
+  wfi
+  bx lr
diff --git a/asm/basepri_max-cm7-r0p1.s b/asm/basepri_max-cm7-r0p1.s
deleted file mode 100644
index 57cbe0c..0000000
--- a/asm/basepri_max-cm7-r0p1.s
+++ /dev/null
@@ -1,12 +0,0 @@
-  .global __basepri_max
-  .syntax unified
-  .thumb_func
-__basepri_max:
-  mrs r1, PRIMASK
-  cpsid i
-  tst.w r1, #1
-  msr BASEPRI_MAX, r0
-  it ne
-  bxne lr
-  cpsie i
-  bx lr
diff --git a/asm/basepri_max.s b/asm/basepri_max.s
deleted file mode 100644
index 32bef7c..0000000
--- a/asm/basepri_max.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __basepri_max
-  .thumb_func
-__basepri_max:
-  msr BASEPRI_MAX, r0
-  bx lr
diff --git a/asm/basepri_r.s b/asm/basepri_r.s
deleted file mode 100644
index 971b152..0000000
--- a/asm/basepri_r.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __basepri_r
-  .thumb_func
-__basepri_r:
-  mrs r0, BASEPRI
-  bx lr
diff --git a/asm/basepri_w-cm7-r0p1.s b/asm/basepri_w-cm7-r0p1.s
deleted file mode 100644
index 4f74f57..0000000
--- a/asm/basepri_w-cm7-r0p1.s
+++ /dev/null
@@ -1,12 +0,0 @@
-  .global __basepri_w
-  .syntax unified
-  .thumb_func
-__basepri_w:
-  mrs r1, PRIMASK
-  cpsid i
-  tst.w r1, #1
-  msr BASEPRI, r0
-  it ne
-  bxne lr
-  cpsie i
-  bx lr
diff --git a/asm/basepri_w.s b/asm/basepri_w.s
deleted file mode 100644
index 323d42d..0000000
--- a/asm/basepri_w.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __basepri_w
-  .thumb_func
-__basepri_w:
-  msr BASEPRI, r0
-  bx lr
diff --git a/asm/bkpt.s b/asm/bkpt.s
deleted file mode 100644
index 5789899..0000000
--- a/asm/bkpt.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __bkpt
-  .thumb_func
-__bkpt:
-  bkpt
-  bx lr
diff --git a/asm/control.s b/asm/control.s
deleted file mode 100644
index ae1ac7e..0000000
--- a/asm/control.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __control
-  .thumb_func
-__control:
-  mrs r0, CONTROL
-  bx lr
diff --git a/asm/cpsid.s b/asm/cpsid.s
deleted file mode 100644
index c52408a..0000000
--- a/asm/cpsid.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __cpsid
-  .thumb_func
-__cpsid:
-  cpsid i
-  bx lr
diff --git a/asm/cpsie.s b/asm/cpsie.s
deleted file mode 100644
index 22556ff..0000000
--- a/asm/cpsie.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __cpsie
-  .thumb_func
-__cpsie:
-  cpsie i
-  bx lr
diff --git a/asm/delay.s b/asm/delay.s
deleted file mode 100644
index 2bf92f1..0000000
--- a/asm/delay.s
+++ /dev/null
@@ -1,8 +0,0 @@
-  .global __delay
-  .syntax unified
-  .thumb_func
-__delay:
-  nop
-  subs r0, #1
-  bne __delay
-  bx lr
diff --git a/asm/dmb.s b/asm/dmb.s
deleted file mode 100644
index c8cc6af..0000000
--- a/asm/dmb.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __dmb
-  .thumb_func
-__dmb:
-  dmb 0xF
-  bx lr
diff --git a/asm/dsb.s b/asm/dsb.s
deleted file mode 100644
index f4578e9..0000000
--- a/asm/dsb.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __dsb
-  .thumb_func
-__dsb:
-  dsb 0xF
-  bx lr
diff --git a/asm/faultmask.s b/asm/faultmask.s
deleted file mode 100644
index 1db599f..0000000
--- a/asm/faultmask.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __faultmask
-  .thumb_func
-__faultmask:
-  mrs r0, FAULTMASK
-  bx lr
diff --git a/asm/isb.s b/asm/isb.s
deleted file mode 100644
index f48eb86..0000000
--- a/asm/isb.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __isb
-  .thumb_func
-__isb:
-  isb 0xF
-  bx lr
diff --git a/asm/msp_r.s b/asm/msp_r.s
deleted file mode 100644
index 920bac2..0000000
--- a/asm/msp_r.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __msp_r
-  .thumb_func
-__msp_r:
-  mrs r0, MSP
-  bx lr
diff --git a/asm/msp_w.s b/asm/msp_w.s
deleted file mode 100644
index b4b6c3e..0000000
--- a/asm/msp_w.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __msp_w
-  .thumb_func
-__msp_w:
-  msr MSP, r0
-  bx lr
diff --git a/asm/nop.s b/asm/nop.s
deleted file mode 100644
index 36e8273..0000000
--- a/asm/nop.s
+++ /dev/null
@@ -1,4 +0,0 @@
-  .global __nop
-  .thumb_func
-__nop:
-  bx lr
diff --git a/asm/primask.s b/asm/primask.s
deleted file mode 100644
index 9735008..0000000
--- a/asm/primask.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __primask
-  .thumb_func
-__primask:
-  mrs r0, PRIMASK
-  bx lr
diff --git a/asm/psp_r.s b/asm/psp_r.s
deleted file mode 100644
index ea093b3..0000000
--- a/asm/psp_r.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __psp_r
-  .thumb_func
-__psp_r:
-  mrs r0, PSP
-  bx lr
diff --git a/asm/psp_w.s b/asm/psp_w.s
deleted file mode 100644
index dee5a79..0000000
--- a/asm/psp_w.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __psp_w
-  .thumb_func
-__psp_w:
-  msr PSP, r0
-  bx lr
diff --git a/asm/sev.s b/asm/sev.s
deleted file mode 100644
index d924c6e..0000000
--- a/asm/sev.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __sev
-  .thumb_func
-__sev:
-  sev
-  bx lr
diff --git a/asm/wfe.s b/asm/wfe.s
deleted file mode 100644
index 35eb1ed..0000000
--- a/asm/wfe.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __wfe
-  .thumb_func
-__wfe:
-  wfe
-  bx lr
diff --git a/asm/wfi.s b/asm/wfi.s
deleted file mode 100644
index d7c2152..0000000
--- a/asm/wfi.s
+++ /dev/null
@@ -1,5 +0,0 @@
-  .global __wfi
-  .thumb_func
-__wfi:
-  wfi
-  bx lr
diff --git a/assemble.sh b/assemble.sh
new file mode 100755
index 0000000..b0a4b3e
--- /dev/null
+++ b/assemble.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+
+set -euxo pipefail
+
+# cflags taken from cc 1.0.22
+
+crate=cortex-m
+
+arm-none-eabi-as -march=armv6s-m asm.s -o bin/$crate.o
+ar crs bin/thumbv6m-none-eabi.a bin/$crate.o
+
+arm-none-eabi-as -march=armv7-m asm.s -o bin/$crate.o
+arm-none-eabi-as -march=armv7-m asm-v7.s -o bin/$crate-v7.o
+ar crs bin/thumbv7m-none-eabi.a bin/$crate.o bin/$crate-v7.o
+
+arm-none-eabi-as -march=armv7e-m asm.s -o bin/$crate.o
+arm-none-eabi-as -march=armv7e-m asm-v7.s -o bin/$crate-v7.o
+arm-none-eabi-as -march=armv7e-m asm-cm7-r0p1.s -o bin/$crate-cm7-r0p1.o
+ar crs bin/thumbv7em-none-eabi.a bin/$crate.o bin/$crate-v7.o bin/$crate-cm7-r0p1.o
+ar crs bin/thumbv7em-none-eabihf.a bin/$crate.o bin/$crate-v7.o bin/$crate-cm7-r0p1.o
+
+rm bin/$crate.o
+rm bin/$crate-v7.o
+rm bin/$crate-cm7-r0p1.o
diff --git a/bin/thumbv6m-none-eabi.a b/bin/thumbv6m-none-eabi.a
new file mode 100644
index 0000000..0aa131e
--- /dev/null
+++ b/bin/thumbv6m-none-eabi.a
diff --git a/bin/thumbv7em-none-eabi.a b/bin/thumbv7em-none-eabi.a
new file mode 100644
index 0000000..91bd58a
--- /dev/null
+++ b/bin/thumbv7em-none-eabi.a
diff --git a/bin/thumbv7em-none-eabihf.a b/bin/thumbv7em-none-eabihf.a
new file mode 100644
index 0000000..91bd58a
--- /dev/null
+++ b/bin/thumbv7em-none-eabihf.a
diff --git a/bin/thumbv7m-none-eabi.a b/bin/thumbv7m-none-eabi.a
new file mode 100644
index 0000000..5396940
--- /dev/null
+++ b/bin/thumbv7m-none-eabi.a
diff --git a/build.rs b/build.rs
index e3797a7..6d08ba9 100644
--- a/build.rs
+++ b/build.rs
@@ -1,48 +1,19 @@
-extern crate cc;
-
-use std::env;
+use std::path::PathBuf;
+use std::{env, fs};
 
 fn main() {
     let target = env::var("TARGET").unwrap();
-
-    let is_v6 = target.starts_with("thumbv6m-");
+    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
+    let name = env::var("CARGO_PKG_NAME").unwrap();
 
     if target.starts_with("thumb") && env::var_os("CARGO_FEATURE_INLINE_ASM").is_none() {
-        // NOTE we need to place each routine in a separate assembly file or the linker won't be
-        // able to discard the unused routines
-        let mut build = cc::Build::new();
-        build
-            .file("asm/bkpt.s")
-            .file("asm/control.s")
-            .file("asm/cpsid.s")
-            .file("asm/cpsie.s")
-            .file("asm/delay.s")
-            .file("asm/dmb.s")
-            .file("asm/dsb.s")
-            .file("asm/isb.s")
-            .file("asm/msp_r.s")
-            .file("asm/msp_w.s")
-            .file("asm/nop.s")
-            .file("asm/primask.s")
-            .file("asm/psp_r.s")
-            .file("asm/psp_w.s")
-            .file("asm/sev.s")
-            .file("asm/wfe.s")
-            .file("asm/wfi.s");
-
-        if !is_v6 {
-            build.file("asm/basepri_r.s").file("asm/faultmask.s");
-
-            if env::var_os("CARGO_FEATURE_CM7_R0P1").is_some() {
-                build.file("asm/basepri_max-cm7-r0p1.s");
-                build.file("asm/basepri_w-cm7-r0p1.s");
-            } else {
-                build.file("asm/basepri_max.s");
-                build.file("asm/basepri_w.s");
-            }
-        }
+        fs::copy(
+            format!("bin/{}.a", target),
+            out_dir.join(format!("lib{}.a", name)),
+        ).unwrap();
 
-        build.compile("asm");
+        println!("cargo:rustc-link-lib=static={}", name);
+        println!("cargo:rustc-link-search={}", out_dir.display());
     }
 
     if target.starts_with("thumbv6m-") {
diff --git a/check-blobs.sh b/check-blobs.sh
new file mode 100755
index 0000000..94fde42
--- /dev/null
+++ b/check-blobs.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+
+# Checks that the blobs are up to date with the committed assembly files
+
+set -euxo pipefail
+
+for lib in $(ls bin/*.a); do
+    filename=$(basename $lib)
+    arm-none-eabi-objdump -Cd $lib > bin/${filename%.a}.before
+done
+
+./assemble.sh
+
+for lib in $(ls bin/*.a); do
+    filename=$(basename $lib)
+    arm-none-eabi-objdump -Cd $lib > bin/${filename%.a}.after
+done
+
+for cksum in $(ls bin/*.after); do
+    diff -u $cksum ${cksum%.after}.before
+done
diff --git a/ci/install.sh b/ci/install.sh
index a0cbf43..495e51d 100644
--- a/ci/install.sh
+++ b/ci/install.sh
@@ -6,6 +6,10 @@ main() {
             rustup target add $TARGET
             ;;
     esac
+
+    mkdir gcc
+
+    curl -L https://developer.arm.com/-/media/Files/downloads/gnu-rm/7-2018q2/gcc-arm-none-eabi-7-2018-q2-update-linux.tar.bz2?revision=bc2c96c0-14b5-4bb4-9f18-bceb4050fee7?product=GNU%20Arm%20Embedded%20Toolchain,64-bit,,Linux,7-2018-q2-update | tar --strip-components=1 -C gcc -xj
 }
 
 # NOTE(TRAVIS_BRANCH) Travis is configured to only build *pushes* (not PRs)
diff --git a/ci/script.sh b/ci/script.sh
index 9fd46a3..b088d95 100644
--- a/ci/script.sh
+++ b/ci/script.sh
@@ -23,6 +23,10 @@ main() {
             cargo test --target $TARGET
             ;;
     esac
+
+    if [ $TARGET = x86_64-unknown-linux-gnu ]; then
+        ./check-blobs.sh
+    fi
 }
 
 # NOTE See the NOTE in `install.sh`
diff --git a/src/register/basepri.rs b/src/register/basepri.rs
index c9f09cc..a9cd6ef 100644
--- a/src/register/basepri.rs
+++ b/src/register/basepri.rs
@@ -45,13 +45,24 @@ pub unsafe fn write(_basepri: u8) {
         },
 
         #[cfg(all(cortex_m, not(feature = "inline-asm")))]
-        () => {
-            extern "C" {
-                fn __basepri_w(_: u8);
+        () => match () {
+            #[cfg(not(feature = "cm7-r0p1"))]
+            () => {
+                extern "C" {
+                    fn __basepri_w(_: u8);
+                }
+
+                __basepri_w(_basepri);
             }
+            #[cfg(feature = "cm7-r0p1")]
+            () => {
+                extern "C" {
+                    fn __basepri_w_cm7_r0p1(_: u8);
+                }
 
-            __basepri_w(_basepri);
-        }
+                __basepri_w_cm7_r0p1(_basepri);
+            }
+        },
 
         #[cfg(not(cortex_m))]
         () => unimplemented!(),
diff --git a/src/register/basepri_max.rs b/src/register/basepri_max.rs
index 91698b6..59ddb44 100644
--- a/src/register/basepri_max.rs
+++ b/src/register/basepri_max.rs
@@ -24,11 +24,24 @@ pub fn write(_basepri: u8) {
 
         #[cfg(all(cortex_m, not(feature = "inline-asm")))]
         () => unsafe {
-            extern "C" {
-                fn __basepri_max(_: u8);
-            }
+            match () {
+                #[cfg(not(feature = "cm7-r0p1"))]
+                () => {
+                    extern "C" {
+                        fn __basepri_max(_: u8);
+                    }
 
-            __basepri_max(_basepri)
+                    __basepri_max(_basepri)
+                }
+                #[cfg(feature = "cm7-r0p1")]
+                () => {
+                    extern "C" {
+                        fn __basepri_max_cm7_r0p1(_: u8);
+                    }
+
+                    __basepri_max_cm7_r0p1(_basepri)
+                }
+            }
         },
 
         #[cfg(not(cortex_m))]