Merge pull request #275 from rust-embedded/include-device

Add memory feature

Author: romancardenas

riscv-rt/CHANGELOG.md

@@ -11,6 +11,12 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - New `device` feature to include `device.x` in `link.x`. This feature is based
   on the current implementation of `cortex-m-rt`.
+- New `memory` feature to include `memory.x` in `link.x`. This feature is based
+  on the current implementation of `cortex-m-rt`. However, in contrast with 
+  `cortex-m-rt`, including `memory.x` in the linker file is feature gated.
+  The benefits of leaving this optional are backwards compatibility and
+  allowing users to define less typical linker scripts that do not rely on a
+  `device.x` or `memory.x` file.
 
 ### Changed
 

riscv-rt/Cargo.toml

@@ -38,3 +38,4 @@ u-boot = ["riscv-rt-macros/u-boot", "single-hart"]
 no-interrupts = []
 no-exceptions = []
 device = []
+memory = []

riscv-rt/build.rs

@@ -29,6 +29,11 @@ fn add_linker_script(arch_width: u32) -> io::Result<()> {
         include_content.push_str("/* Device-specific exception and interrupt handlers */\n");
         include_content.push_str("INCLUDE device.x\n");
     }
+    // If memory is enabled, include the memory.x file (usually, provided by BSPs)
+    if env::var_os("CARGO_FEATURE_MEMORY").is_some() {
+        include_content.push_str("/* Device-specific memory layout */\n");
+        include_content.push_str("INCLUDE memory.x\n");
+    }
 
     content = content.replace("${INCLUDE_LINKER_FILES}", &include_content);