add relibm crate

.gitignore

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

Cargo.toml

@@ -25,6 +25,7 @@ musl-reference-tests = ['rand']
 members = [
   "crates/compiler-builtins-smoke-test",
   "crates/libm-bench",
+  "crates/libm-c-abi"
 ]
 
 [dev-dependencies]

crates/libm-c-abi/Cargo.toml

@@ -0,0 +1,14 @@
+[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"]
+
+[dependencies]
+libm = { path = "../.." }
+libc = {version="0.2", default-features=false}

crates/libm-c-abi/example/Makefile

@@ -0,0 +1,15 @@
+mkfile_path := $(abspath $(lastword $(MAKEFILE_LIST)))
+mkfile_dir := $(dir $(mkfile_path))
+
+ifndef CARGO_TARGET_DIR
+override CARGO_TARGET_DIR = "../"
+endif
+CRATE_RELEASE_DIR := $(CARGO_TARGET_DIR)release
+LDLIBS += -L $(CRATE_RELEASE_DIR) -lrelibm -Wl,-rpath=$(CRATE_RELEASE_DIR)
+
+all: shared
+
+shared:
+	clang simple.c $(LDLIBS)
+static:
+	clang simple.c $(CRATE_RELEASE_DIR)/librelibm.a

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

@@ -0,0 +1,15 @@
+/* 
+* 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;
+    double got = -0x1p-55;
+    printf("want: %a : got : %a\ngot in test : %a\n", want, res, got);
+}

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

@@ -0,0 +1,12 @@
+mod lib_f32;
+mod lib_f64;
+mod lib_fenv;
+mod lib_long_double;
+
+pub use lib_f32::*;
+pub use lib_f64::*;
+pub use lib_fenv::*;
+pub use lib_long_double::*;
+
+#[no_mangle]
+pub static mut signgam: i32 = 0;