Put Rust binding generation behind an explicit flag and only build bindings for the targeted Arch
Change-Id: I8ccd53bce0d73bd9d79f65770e544a75753ce4f8
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/51025
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7f02b29..f74e233 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,7 +31,6 @@
else()
find_package(Perl REQUIRED)
find_program(GO_EXECUTABLE go)
- find_program(BINDGEN_EXECUTABLE bindgen)
endif()
if(CMAKE_SYSTEM_NAME STREQUAL "Linux" AND NOT CMAKE_CROSSCOMPILING)
@@ -52,12 +51,6 @@
message(FATAL_ERROR "Could not find Go")
endif()
-if(NOT BINDGEN_EXECUTABLE)
- message("Could not find bindgen. Not generating Rust bindings.")
-else()
- add_subdirectory(rust)
-endif()
-
if(USE_CUSTOM_LIBCXX)
set(BORINGSSL_ALLOW_CXX_RUNTIME 1)
endif()
@@ -615,6 +608,15 @@
add_subdirectory(fuzz)
endif()
+if(RUST_BINDINGS)
+ find_program(BINDGEN_EXECUTABLE bindgen)
+ if(NOT BINDGEN_EXECUTABLE)
+ message(FATAL_ERROR "Could not find bindgen but was asked to generate Rust bindings.")
+ else()
+ add_subdirectory(rust)
+ endif()
+endif()
+
if(UNIX AND NOT APPLE AND NOT ANDROID)
set(HANDSHAKER_ARGS "-handshaker-path" $<TARGET_FILE:handshaker>)
endif()
diff --git a/rust/CMakeLists.txt b/rust/CMakeLists.txt
index d830bdd..f60ad47 100644
--- a/rust/CMakeLists.txt
+++ b/rust/CMakeLists.txt
@@ -6,57 +6,46 @@
)
# generate architecture specific wrappers
-foreach(TARGET
- aarch64-unknown-linux-gnu
- i686-pc-windows-gnu
- x86_64-unknown-linux-gnu
- )
+set(WRAPPER_TARGET ${CMAKE_BINARY_DIR}/rust/src/wrapper_${RUST_BINDINGS}.rs)
+set(COMMAND ${BINDGEN_EXECUTABLE} "wrapper.h"
+ -o ${WRAPPER_TARGET}
+ --no-derive-default
+ --enable-function-attribute-detection
+ --use-core
+ --size_t-is-usize
+ --default-macro-constant-type="signed"
+ --rustified-enum="point_conversion_form_t"
+ # These are not BoringSSL symbols, they are from glibc
+ # and are not relevant to the build besides throwing warnings
+ # about their 'long double' (aka u128) not being FFI safe.
+ # We block those functions so that the build doesn't
+ # spam warnings.
+ #
+ # https://github.com/rust-lang/rust-bindgen/issues/1549 describes the current problem
+ # and other folks' solutions.
+ #
+ # We will explore migrating to https://github.com/rust-lang/rust-bindgen/pull/2122
+ # when it lands
+ --blocklist-function="strtold"
+ --blocklist-function="qecvt"
+ --blocklist-function="qecvt_r"
+ --blocklist-function="qgcvt"
+ --blocklist-function="qfcvt"
+ --blocklist-function="qfcvt_r"
+ -- # these are LLVM arg passthroughs
+ -I../include
+ # https://doc.rust-lang.org/nightly/rustc/platform-support.html
+ --target=${RUST_BINDINGS})
- set(WRAPPER_TARGET ${CMAKE_BINARY_DIR}/rust/src/wrapper_${TARGET}.rs)
- set(COMMAND ${BINDGEN_EXECUTABLE} "wrapper.h"
- -o ${WRAPPER_TARGET}
- --no-derive-default
- --enable-function-attribute-detection
- --use-core
- --size_t-is-usize
- --default-macro-constant-type="signed"
- --rustified-enum="point_conversion_form_t"
- # These are not BoringSSL symbols, they are from glibc
- # and are not relevant to the build besides throwing warnings
- # about their 'long double' (aka u128) not being FFI safe.
- # We block those functions so that the build doesn't
- # spam warnings.
- #
- # https://github.com/rust-lang/rust-bindgen/issues/1549 describes the current problem
- # and other folks' solutions.
- #
- # We will explore migrating to https://github.com/rust-lang/rust-bindgen/pull/2122
- # when it lands
- --blocklist-function="strtold"
- --blocklist-function="qecvt"
- --blocklist-function="qecvt_r"
- --blocklist-function="qgcvt"
- --blocklist-function="qfcvt"
- --blocklist-function="qfcvt_r"
- -- # these are LLVM arg passthroughs
- -I../include
- --target=${TARGET})
+set(INCLUDES "include!(\"wrapper_${RUST_BINDINGS}.rs\");\n")
- add_custom_target(
- bindgen_rust_${TARGET}
- ALL
- ${COMMAND}
- BYPRODUCTS ${WRAPPER_TARGET}
- WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
- )
- string(REPLACE "-" ";" TARGET_LIST ${TARGET})
- list(GET TARGET_LIST 0 ARCH)
- list(GET TARGET_LIST 1 VENDOR)
-
- set(INCLUDES "${INCLUDES}\
- #[cfg(all(target_arch = \"${ARCH}\", target_vendor = \"${VENDOR}\"))]\n\
- include!(\"wrapper_${TARGET}.rs\");\n")
-endforeach()
+add_custom_target(
+ bindgen_rust_${RUST_BINDINGS}
+ ALL
+ ${COMMAND}
+ BYPRODUCTS ${WRAPPER_TARGET}
+ WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+)
# move files into build directory
configure_file("src/lib.rs" "src/lib.rs")
diff --git a/rust/README.md b/rust/README.md
index 271d4d5..fb5230a 100644
--- a/rust/README.md
+++ b/rust/README.md
@@ -4,5 +4,10 @@
A low-level binding crate for Rust that moves in lockstop with BoringSSL. BoringSSL explicitly does not have a stable ABI, `bssl-sys` is the solution for preventing subtle-memory corruption bugs due to version skew.
### How it works
-`bssl-sys` uses `bindgen` as part of the cmake build process to generate Rust compatibility shims for each supported target platform. It is important to generate it for each platform because `bindgen` uses LLVM information for alignment which varies depending on architecture. These files are then packaged into a Rust crate.
+`bssl-sys` uses `bindgen` as part of the cmake build process to generate Rust compatibility shims for the targeted platform. It is important to generate it for the correct platform because `bindgen` uses LLVM information for alignment which varies depending on architecture. These files are then packaged into a Rust crate.
+
+### To Use
+Build `boringssl` with `-DRUST_BINDINGS=<rust-triple>` and ensure that you have `bindgen` installed.
+
+The `rust-triple` option should be one of the supported targets at https://doc.rust-lang.org/nightly/rustc/platform-support.html.
