Linker Scripts

pw_build: Integrations for Bazel, GN, and CMake

pw_build provides utilities for working with linker scripts in embedded projects. If using the GN or Bazel build systems you can preprocess your linker script using the C preprocessor with the pw_linker_script rules.

• GN pw_linker_script

• Bazel pw_linker_script

Linker script C/C++ helpers

• PW_MUST_PLACE: Ensures inputs are non-zero sized

• PW_MUST_PLACE_SIZE: Ensures inputs are an expected size

• PW_MUST_NOT_PLACE: Ensures inputs are not present

• pw::LinkerSymbol: Represents a symbol provided by the linker

Note

LinkerSymbol does not support, and is not necessary for, symbols that communicate a pointer value (i.e. an address). For those, simply define an extern variable of the pointed-to type, e.g.:

extern "C" uint32_t PTR_SYM;

LinkerSymbol is superior to the traditional extern uint8_t FOO; (uint32_t)&FOO method because it catches subtle errors:

• Missing extern specifier:

  error: use of deleted function 'pw::build::LinkerSymbol::LinkerSymbol()'
  | LinkerSymbol oops;
  |              ^~~~
  

• Missing & operator:

  error: invalid cast from type 'pw::build::LinkerSymbol' to type 'uint32_t' {aka 'long unsigned int'}
  |  uint32_t val = (uint32_t)FOO_SYM;
  |                 ^~~~~~~~~~~~~~~~~