about summary refs log tree commit diff
path: root/compiler/rustc_codegen_gcc/doc/tips.md
diff options
context:
space:
mode:
Diffstat (limited to 'compiler/rustc_codegen_gcc/doc/tips.md')
-rw-r--r--compiler/rustc_codegen_gcc/doc/tips.md12
1 files changed, 10 insertions, 2 deletions
diff --git a/compiler/rustc_codegen_gcc/doc/tips.md b/compiler/rustc_codegen_gcc/doc/tips.md
index 1379f5130be..86c22db186e 100644
--- a/compiler/rustc_codegen_gcc/doc/tips.md
+++ b/compiler/rustc_codegen_gcc/doc/tips.md
@@ -35,6 +35,14 @@ COLLECT_NO_DEMANGLE=1
  * Build the stage2 compiler (`rustup toolchain link debug-current build/x86_64-unknown-linux-gnu/stage2`).
  * Clean and rebuild the codegen with `debug-current` in the file `rust-toolchain`.
 
+### How to use a custom sysroot source path
+
+If you wish to build a custom sysroot, pass the path of your sysroot source to `--sysroot-source` during the `prepare` step, like so:
+
+```
+./y.sh prepare --sysroot-source /path/to/custom/source
+```
+
 ### How to use [mem-trace](https://github.com/antoyo/mem-trace)
 
 `rustc` needs to be built without `jemalloc` so that `mem-trace` can overload `malloc` since `jemalloc` is linked statically, so a `LD_PRELOAD`-ed library won't a chance to intercept the calls to `malloc`.
@@ -54,13 +62,13 @@ generate it in [gimple.md](./doc/gimple.md).
 
  * Run `./y.sh prepare --cross` so that the sysroot is patched for the cross-compiling case.
  * Set the path to the cross-compiling libgccjit in `gcc-path` (in `config.toml`).
- * Make sure you have the linker for your target (for instance `m68k-unknown-linux-gnu-gcc`) in your `$PATH`. Currently, the linker name is hardcoded as being `$TARGET-gcc`. Specify the target when building the sysroot: `./y.sh build --target-triple m68k-unknown-linux-gnu`.
+ * Make sure you have the linker for your target (for instance `m68k-unknown-linux-gnu-gcc`) in your `$PATH`. Currently, the linker name is hardcoded as being `$TARGET-gcc`. Specify the target when building the sysroot: `./y.sh build --sysroot --target-triple m68k-unknown-linux-gnu`.
  * Build your project by specifying the target: `OVERWRITE_TARGET_TRIPLE=m68k-unknown-linux-gnu ../y.sh cargo build --target m68k-unknown-linux-gnu`.
 
 If the target is not yet supported by the Rust compiler, create a [target specification file](https://docs.rust-embedded.org/embedonomicon/custom-target.html) (note that the `arch` specified in this file must be supported by the rust compiler).
 Then, you can use it the following way:
 
- * Add the target specification file using `--target` as an **absolute** path to build the sysroot: `./y.sh build --target-triple m68k-unknown-linux-gnu --target $(pwd)/m68k-unknown-linux-gnu.json`
+ * Add the target specification file using `--target` as an **absolute** path to build the sysroot: `./y.sh build --sysroot --target-triple m68k-unknown-linux-gnu --target $(pwd)/m68k-unknown-linux-gnu.json`
  * Build your project by specifying the target specification file: `OVERWRITE_TARGET_TRIPLE=m68k-unknown-linux-gnu ../y.sh cargo build --target path/to/m68k-unknown-linux-gnu.json`.
 
 If you get the following error: