add relibm crate

.gitignore

@@ -6,3 +6,6 @@
 /target
 /tests
 Cargo.lock
+# libm-c-abi tests folders
+libc-test
+openlibm

Cargo.toml

@@ -26,10 +26,11 @@ musl-reference-tests = ['rand']
 members = [
   "crates/compiler-builtins-smoke-test",
   "crates/libm-bench",
+  "crates/libm-c-abi"
 ]
 
 [dev-dependencies]
-no-panic = "0.1.8"
+no-panic = "0.1.15"
 
 [build-dependencies]
-rand = { version = "0.6.5", optional = true }
+rand = { version = "0.8.3", optional = true }

crates/libm-c-abi/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "relibm"
+version = "0.1.0"
+authors = ["augustin <cheron.augustin@gmail.com>"]
+description = "Expose rust libm functions in a c abi compatible library. This is highly experimental. This crate is for test purpose only."
+edition = "2018"
+license = "MIT OR Apache-2.0"
+
+[lib]
+crate-type = ["staticlib", "cdylib"]
+
+[profile.dev]
+panic = "abort"
+
+[profile.release]
+panic = "abort"
+
+[dependencies]
+libm = { path = "../.." }
+libc = { version = "0.2.94", default-features = false }

crates/libm-c-abi/example/Makefile

@@ -0,0 +1,16 @@
+mkfile_path := $(abspath $(lastword $(MAKEFILE_LIST)))
+mkfile_dir := $(dir $(mkfile_path))
+
+ifndef CARGO_TARGET_DIR
+override CARGO_TARGET_DIR = ${mkfile_dir}../../../target
+endif
+
+CRATE_RELEASE_DIR := ${CARGO_TARGET_DIR}/release
+LDLIBS += -L $(CRATE_RELEASE_DIR) -lrelibm -Wl,-rpath=$(CRATE_RELEASE_DIR)
+
+all: static
+
+shared:
+	${CC} -ansi --std=c99  simple.c $(LDLIBS)
+static:
+	${CC} -ansi --std=c99 simple.c $(CRATE_RELEASE_DIR)/librelibm.a

crates/libm-c-abi/example/simple.c

@@ -0,0 +1,14 @@
+/* 
+* Simple test program.
+* You can use it to debug test case outside the test suite.
+* This is usefull to debug in parallel the C and rust version, to float debug precision issue.
+*/
+#include <math.h>
+#include <stdio.h>
+
+int main(void)
+{
+    double res = y0(0x1.c982eb8d417eap-1);
+    double want = -0x1.af74bfa0f1304p-56;
+    printf("want: %a : got : %a\n", want, res);
+}

crates/libm-c-abi/src/lib.rs

@@ -0,0 +1,44 @@
+#![no_std]
+#![feature(lang_items)]
+#![feature(core_intrinsics)]
+use core::intrinsics;
+use core::panic::PanicInfo;
+
+mod lib_f32;
+mod lib_f64;
+mod lib_fenv;
+mod lib_long_double;
+mod musl_missing;
+mod new_lib;
+
+pub use lib_f32::*;
+pub use lib_f64::*;
+pub use lib_fenv::*;
+pub use lib_long_double::*;
+
+pub use musl_missing::*;
+pub use new_lib::*;
+
+#[no_mangle]
+pub static mut signgam: i32 = 0;
+
+
+#[panic_handler]
+fn panic(_info: &PanicInfo) -> ! {
+   intrinsics::abort()
+}
+
+/*
+#[panic_handler]
+fn panic(_: &PanicInfo<'_>) -> ! {
+    extern "Rust" {
+        #[link_name = "\nerror(panic-never): your program contains at least one panicking branch"]
+        fn undefined() -> !;
+    }
+
+    unsafe { undefined() }
+}
+*/
+
+#[lang = "eh_personality"]
+extern "C" fn eh_personality() {}