relibc_compiler-builtins/build.rs

#[cfg(feature = "c")]
extern crate gcc;
extern crate rustc_cfg;

#[cfg(feature = "c")]
use std::collections::BTreeMap;
use std::io::Write;
#[cfg(feature = "c")]
use std::path::Path;
use std::{env, io, process};

use rustc_cfg::Cfg;

#[cfg(feature = "c")]
struct Sources {
    // SYMBOL -> PATH TO SOURCE
    map: BTreeMap<&'static str, &'static str>,
}

#[cfg(feature = "c")]
impl Sources {
    fn new() -> Sources {
        Sources { map: BTreeMap::new() }
    }

    fn extend(&mut self, sources: &[&'static str]) {
        // NOTE Some intrinsics have both a generic implementation (e.g.
        // `floatdidf.c`) and an arch optimized implementation
        // (`x86_64/floatdidf.c`). In those cases, we keep the arch optimized
        // implementation and discard the generic implementation. If we don't
        // and keep both implementations, the linker will yell at us about
        // duplicate symbols!
        for &src in sources {
            let symbol = Path::new(src).file_stem().unwrap().to_str().unwrap();
            if src.contains("/") {
                // Arch-optimized implementation (preferred)
                self.map.insert(symbol, src);
            } else {
                // Generic implementation
                if !self.map.contains_key(symbol) {
                    self.map.insert(symbol, src);
                }
            }
        }
    }

    fn remove(&mut self, symbols: &[&str]) {
        for symbol in symbols {
            self.map.remove(*symbol).unwrap();
        }
    }
}

fn main() {
    println!("cargo:rerun-if-changed=build.rs");

    let target = env::var("TARGET").unwrap();

    // Emscripten's runtime includes all the builtins
    if target.contains("emscripten") {
        return;
    }

    let Cfg { ref target_arch, ref target_os, ref target_env, ref target_vendor, .. } =
        Cfg::new(&target).unwrap_or_else(|e| {
            writeln!(io::stderr(), "{}", e).ok();
            process::exit(1)
        });
    // NOTE we are going to assume that llvm-target, what determines our codegen option, matches the
    // target triple. This is usually correct for our built-in targets but can break in presence of
    // custom targets, which can have arbitrary names.
    let llvm_target = target.split('-').collect::<Vec<_>>();

    // Build missing intrinsics from compiler-rt C source code
    match () {
        #[cfg(feature = "c")]
        () => {
            let target_vendor = target_vendor.as_ref().unwrap();
            let cfg = &mut gcc::Config::new();

            if target_env == "msvc" {
                // Don't pull in extra libraries on MSVC
                cfg.flag("/Zl");

                // Emulate C99 and C++11's __func__ for MSVC prior to 2013 CTP
                cfg.define("__func__", Some("__FUNCTION__"));
            } else {
                // Turn off various features of gcc and such, mostly copying
                // compiler-rt's build system already
                cfg.flag("-fno-builtin");
                cfg.flag("-fvisibility=hidden");
                cfg.flag("-fomit-frame-pointer");
                cfg.flag("-ffreestanding");
                cfg.define("VISIBILITY_HIDDEN", None);
            }

            // NOTE Most of the ARM intrinsics are written in assembly. Tell gcc which arch we are going to
            // target to make sure that the assembly implementations really work for the target. If the
            // implementation is not valid for the arch, then gcc will error when compiling it.
            if llvm_target[0].starts_with("thumb") {
                cfg.flag("-mthumb");

                if llvm_target.last() == Some(&"eabihf") {
                    cfg.flag("-mfloat-abi=hard");
                }
            }

            if llvm_target[0] == "thumbv6m" {
                cfg.flag("-march=armv6-m");
            }

            if llvm_target[0] == "thumbv7m" {
                cfg.flag("-march=armv7-m");
            }

            if llvm_target[0] == "thumbv7em" {
                cfg.flag("-march=armv7e-m");
            }

            let mut sources = Sources::new();
            sources.extend(&["absvdi2.c",
                            "absvsi2.c",
                            "addvdi3.c",
                            "addvsi3.c",
                            "apple_versioning.c",
                            "clzdi2.c",
                            "clzsi2.c",
                            "cmpdi2.c",
                            "comparedf2.c",
                            "comparesf2.c",
                            "ctzdi2.c",
                            "ctzsi2.c",
                            "divdc3.c",
                            "divdf3.c",
                            "divsc3.c",
                            "divsf3.c",
                            "divxc3.c",
                            "extendsfdf2.c",
                            "extendhfsf2.c",
                            "ffsdi2.c",
                            "fixdfdi.c",
                            "fixdfsi.c",
                            "fixsfdi.c",
                            "fixsfsi.c",
                            "fixunsdfdi.c",
                            "fixunsdfsi.c",
                            "fixunssfdi.c",
                            "fixunssfsi.c",
                            "fixunsxfdi.c",
                            "fixunsxfsi.c",
                            "fixxfdi.c",
                            "floatdidf.c",
                            "floatdisf.c",
                            "floatdixf.c",
                            "floatsidf.c",
                            "floatsisf.c",
                            "floatundidf.c",
                            "floatundisf.c",
                            "floatundixf.c",
                            "floatunsidf.c",
                            "floatunsisf.c",
                            "int_util.c",
                            "muldc3.c",
                            "muldf3.c",
                            "mulsc3.c",
                            "mulsf3.c",
                            "mulvdi3.c",
                            "mulvsi3.c",
                            "mulxc3.c",
                            "negdf2.c",
                            "negdi2.c",
                            "negsf2.c",
                            "negvdi2.c",
                            "negvsi2.c",
                            "paritydi2.c",
                            "paritysi2.c",
                            "popcountdi2.c",
                            "popcountsi2.c",
                            "powixf2.c",
                            "subvdi3.c",
                            "subvsi3.c",
                            "truncdfhf2.c",
                            "truncdfsf2.c",
                            "truncsfhf2.c",
                            "ucmpdi2.c"]);

            if target_os != "ios" {
                sources.extend(&["absvti2.c",
                                "addvti3.c",
                                "clzti2.c",
                                "cmpti2.c",
                                "ctzti2.c",
                                "ffsti2.c",
                                "fixdfti.c",
                                "fixsfti.c",
                                "fixunsdfti.c",
                                "fixunssfti.c",
                                "fixunsxfti.c",
                                "fixxfti.c",
                                "floattidf.c",
                                "floattisf.c",
                                "floattixf.c",
                                "floatuntidf.c",
                                "floatuntisf.c",
                                "floatuntixf.c",
                                "mulvti3.c",
                                "negti2.c",
                                "negvti2.c",
                                "parityti2.c",
                                "popcountti2.c",
                                "subvti3.c",
                                "ucmpti2.c"]);
            }

            if target_vendor == "apple" {
                sources.extend(&["atomic_flag_clear.c",
                                "atomic_flag_clear_explicit.c",
                                "atomic_flag_test_and_set.c",
                                "atomic_flag_test_and_set_explicit.c",
                                "atomic_signal_fence.c",
                                "atomic_thread_fence.c"]);
            }

            if target_env == "msvc" {
                if target_arch == "x86_64" {
                    sources.extend(&["x86_64/floatdidf.c", "x86_64/floatdisf.c", "x86_64/floatdixf.c"]);
                }
            } else {
                if target_os != "freebsd" && target_os != "netbsd" {
                    sources.extend(&["gcc_personality_v0.c"]);
                }

                if target_arch == "x86_64" {
                    sources.extend(&["x86_64/chkstk.S",
                                    "x86_64/chkstk2.S",
                                    "x86_64/floatdidf.c",
                                    "x86_64/floatdisf.c",
                                    "x86_64/floatdixf.c",
                                    "x86_64/floatundidf.S",
                                    "x86_64/floatundisf.S",
                                    "x86_64/floatundixf.S"]);
                }

                if target_arch == "x86" {
                    sources.extend(&["i386/ashldi3.S",
                                    "i386/ashrdi3.S",
                                    "i386/chkstk.S",
                                    "i386/chkstk2.S",
                                    "i386/divdi3.S",
                                    "i386/floatdidf.S",
                                    "i386/floatdisf.S",
                                    "i386/floatdixf.S",
                                    "i386/floatundidf.S",
                                    "i386/floatundisf.S",
                                    "i386/floatundixf.S",
                                    "i386/lshrdi3.S",
                                    "i386/moddi3.S",
                                    "i386/muldi3.S",
                                    "i386/udivdi3.S",
                                    "i386/umoddi3.S"]);
                }
            }

            if target_arch == "arm" && target_os != "ios" {
                sources.extend(&["arm/aeabi_cdcmp.S",
                                "arm/aeabi_cdcmpeq_check_nan.c",
                                "arm/aeabi_cfcmp.S",
                                "arm/aeabi_cfcmpeq_check_nan.c",
                                "arm/aeabi_dcmp.S",
                                "arm/aeabi_div0.c",
                                "arm/aeabi_drsub.c",
                                "arm/aeabi_fcmp.S",
                                "arm/aeabi_frsub.c",
                                "arm/bswapdi2.S",
                                "arm/bswapsi2.S",
                                "arm/clzdi2.S",
                                "arm/clzsi2.S",
                                "arm/comparesf2.S",
                                "arm/divmodsi4.S",
                                "arm/divsi3.S",
                                "arm/modsi3.S",
                                "arm/switch16.S",
                                "arm/switch32.S",
                                "arm/switch8.S",
                                "arm/switchu8.S",
                                "arm/sync_synchronize.S",
                                "arm/udivmodsi4.S",
                                "arm/udivsi3.S",
                                "arm/umodsi3.S"]);
            }

            if llvm_target[0] == "armv7" {
                sources.extend(&["arm/sync_fetch_and_add_4.S",
                                "arm/sync_fetch_and_add_8.S",
                                "arm/sync_fetch_and_and_4.S",
                                "arm/sync_fetch_and_and_8.S",
                                "arm/sync_fetch_and_max_4.S",
                                "arm/sync_fetch_and_max_8.S",
                                "arm/sync_fetch_and_min_4.S",
                                "arm/sync_fetch_and_min_8.S",
                                "arm/sync_fetch_and_nand_4.S",
                                "arm/sync_fetch_and_nand_8.S",
                                "arm/sync_fetch_and_or_4.S",
                                "arm/sync_fetch_and_or_8.S",
                                "arm/sync_fetch_and_sub_4.S",
                                "arm/sync_fetch_and_sub_8.S",
                                "arm/sync_fetch_and_umax_4.S",
                                "arm/sync_fetch_and_umax_8.S",
                                "arm/sync_fetch_and_umin_4.S",
                                "arm/sync_fetch_and_umin_8.S",
                                "arm/sync_fetch_and_xor_4.S",
                                "arm/sync_fetch_and_xor_8.S"]);
            }

            if llvm_target.last().unwrap().ends_with("eabihf") {
                if !llvm_target[0].starts_with("thumbv7em") {
                    sources.extend(&["arm/adddf3vfp.S",
                                    "arm/addsf3vfp.S",
                                    "arm/divdf3vfp.S",
                                    "arm/divsf3vfp.S",
                                    "arm/eqdf2vfp.S",
                                    "arm/eqsf2vfp.S",
                                    "arm/extendsfdf2vfp.S",
                                    "arm/fixdfsivfp.S",
                                    "arm/fixsfsivfp.S",
                                    "arm/fixunsdfsivfp.S",
                                    "arm/fixunssfsivfp.S",
                                    "arm/floatsidfvfp.S",
                                    "arm/floatsisfvfp.S",
                                    "arm/floatunssidfvfp.S",
                                    "arm/floatunssisfvfp.S",
                                    "arm/gedf2vfp.S",
                                    "arm/gesf2vfp.S",
                                    "arm/gtdf2vfp.S",
                                    "arm/gtsf2vfp.S",
                                    "arm/ledf2vfp.S",
                                    "arm/lesf2vfp.S",
                                    "arm/ltdf2vfp.S",
                                    "arm/ltsf2vfp.S",
                                    "arm/muldf3vfp.S",
                                    "arm/mulsf3vfp.S",
                                    "arm/nedf2vfp.S",
                                    "arm/nesf2vfp.S",
                                    "arm/restore_vfp_d8_d15_regs.S",
                                    "arm/save_vfp_d8_d15_regs.S",
                                    "arm/subdf3vfp.S",
                                    "arm/subsf3vfp.S"]);
                }

                sources.extend(&["arm/negdf2vfp.S", "arm/negsf2vfp.S"]);

            }

            if target_arch == "aarch64" {
                sources.extend(&["comparetf2.c",
                                "extenddftf2.c",
                                "extendsftf2.c",
                                "fixtfdi.c",
                                "fixtfsi.c",
                                "fixtfti.c",
                                "fixunstfdi.c",
                                "fixunstfsi.c",
                                "fixunstfti.c",
                                "floatditf.c",
                                "floatsitf.c",
                                "floatunditf.c",
                                "floatunsitf.c",
                                "multc3.c",
                                "trunctfdf2.c",
                                "trunctfsf2.c"]);
            }

            // Remove the assembly implementations that won't compile for the target
            if llvm_target[0] == "thumbv6m" {
                sources.remove(&["aeabi_cdcmp",
                                "aeabi_cfcmp",
                                "aeabi_dcmp",
                                "aeabi_fcmp",
                                "clzdi2",
                                "clzsi2",
                                "comparesf2",
                                "divmodsi4",
                                "divsi3",
                                "modsi3",
                                "switch16",
                                "switch32",
                                "switch8",
                                "switchu8",
                                "udivmodsi4",
                                "udivsi3",
                                "umodsi3"]);

                // But use some generic implementations where possible
                sources.extend(&["clzdi2.c", "clzsi2.c"])
            }

            if llvm_target[0] == "thumbv7m" || llvm_target[0] == "thumbv7em" {
                sources.remove(&["aeabi_cdcmp", "aeabi_cfcmp"]);
            }

            let root = if env::var_os("CARGO_FEATURE_RUSTBUILD").is_some() {
                Path::new("../../libcompiler_builtins")
            } else {
                Path::new(".")
            };

            let src_dir = root.join("compiler-rt/compiler-rt-cdylib/compiler-rt/lib/builtins");
            for src in sources.map.values() {
                let src = src_dir.join(src);
                cfg.file(&src);
                println!("cargo:rerun-if-changed={}", src.display());
            }

            cfg.compile("libcompiler-rt.a");
        }
        #[cfg(not(feature = "c"))]
        () => {}
    }

    // To filter away some flaky test (see src/float/add.rs for details)
    if llvm_target[0].starts_with("arm") &&
       llvm_target.last().unwrap().contains("gnueabi") {
        println!("cargo:rustc-cfg=arm_linux")
    }

    // To compile intrinsics.rs for thumb targets, where there is no libc
    if llvm_target[0].starts_with("thumb") {
        println!("cargo:rustc-cfg=thumb")
    }

    // compiler-rt `cfg`s away some intrinsics for thumbv6m because that target doesn't have full
    // THUMBv2 support. We have to cfg our code accordingly.
    if llvm_target[0] == "thumbv6m" {
        println!("cargo:rustc-cfg=thumbv6m")
    }
}