Auto merge of #45725 - alexcrichton:std-less-rand, r=dtolnay

Working towards a libc-less (wasm32) libstd

This is a series of commits I was able to extract from prepare to comiple libstd on a "bare libc-less" target, notably wasm32. The actual wasm32 bits I intend to send in a PR later, this is just some internal refactorings required for libstd to work with a `libc` that's empty and a few other assorted refactorings.

No functional change should be included in this PR for users of libstd, this is intended to just be internal refactorings.

8 files changed, 142 insertions, 46 deletions

diff --git a/src/libstd/sys/windows/backtrace/mod.rs b/src/libstd/sys/windows/backtrace/mod.rs
index 26b4cb90e0a..176891fff23 100644
--- a/src/libstd/sys/windows/backtrace/mod.rs
+++ b/src/libstd/sys/windows/backtrace/mod.rs
@@ -95,8 +95,8 @@ pub fn unwind_backtrace(frames: &mut [Frame])
                frame.AddrReturn.Offset == 0 { break }
 
             frames[i] = Frame {
-                symbol_addr: (addr - 1) as *const c_void,
-                exact_position: (addr - 1) as *const c_void,
+                symbol_addr: (addr - 1) as *const u8,
+                exact_position: (addr - 1) as *const u8,
             };
             i += 1;
         }
diff --git a/src/libstd/sys/windows/backtrace/printing/msvc.rs b/src/libstd/sys/windows/backtrace/printing/msvc.rs
index 3107d784324..5a49b77af8e 100644
--- a/src/libstd/sys/windows/backtrace/printing/msvc.rs
+++ b/src/libstd/sys/windows/backtrace/printing/msvc.rs
@@ -10,7 +10,7 @@
 
 use ffi::CStr;
 use io;
-use libc::{c_ulong, c_int, c_char};
+use libc::{c_ulong, c_char};
 use mem;
 use sys::c;
 use sys::backtrace::BacktraceContext;
@@ -59,7 +59,7 @@ pub fn foreach_symbol_fileline<F>(frame: Frame,
                                   mut f: F,
                                   context: &BacktraceContext)
     -> io::Result<bool>
-    where F: FnMut(&[u8], c_int) -> io::Result<()>
+    where F: FnMut(&[u8], u32) -> io::Result<()>
 {
     let SymGetLineFromAddr64 = sym!(&context.dbghelp,
                                     "SymGetLineFromAddr64",
@@ -76,7 +76,7 @@ pub fn foreach_symbol_fileline<F>(frame: Frame,
                                        &mut line);
         if ret == c::TRUE {
             let name = CStr::from_ptr(line.Filename).to_bytes();
-            f(name, line.LineNumber as c_int)?;
+            f(name, line.LineNumber as u32)?;
         }
         Ok(false)
     }
diff --git a/src/libstd/sys/windows/cmath.rs b/src/libstd/sys/windows/cmath.rs
new file mode 100644
index 00000000000..b665a2c9ba4
--- /dev/null
+++ b/src/libstd/sys/windows/cmath.rs
@@ -0,0 +1,103 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![cfg(not(test))]
+
+use libc::{c_float, c_double};
+
+#[link_name = "m"]
+extern {
+    pub fn acos(n: c_double) -> c_double;
+    pub fn asin(n: c_double) -> c_double;
+    pub fn atan(n: c_double) -> c_double;
+    pub fn atan2(a: c_double, b: c_double) -> c_double;
+    pub fn cbrt(n: c_double) -> c_double;
+    pub fn cbrtf(n: c_float) -> c_float;
+    pub fn cosh(n: c_double) -> c_double;
+    pub fn expm1(n: c_double) -> c_double;
+    pub fn expm1f(n: c_float) -> c_float;
+    pub fn fdim(a: c_double, b: c_double) -> c_double;
+    pub fn fdimf(a: c_float, b: c_float) -> c_float;
+    #[cfg_attr(target_env = "msvc", link_name = "_hypot")]
+    pub fn hypot(x: c_double, y: c_double) -> c_double;
+    #[cfg_attr(target_env = "msvc", link_name = "_hypotf")]
+    pub fn hypotf(x: c_float, y: c_float) -> c_float;
+    pub fn log1p(n: c_double) -> c_double;
+    pub fn log1pf(n: c_float) -> c_float;
+    pub fn sinh(n: c_double) -> c_double;
+    pub fn tan(n: c_double) -> c_double;
+    pub fn tanh(n: c_double) -> c_double;
+}
+
+pub use self::shims::*;
+
+#[cfg(not(target_env = "msvc"))]
+mod shims {
+    use libc::c_float;
+
+    extern {
+        pub fn acosf(n: c_float) -> c_float;
+        pub fn asinf(n: c_float) -> c_float;
+        pub fn atan2f(a: c_float, b: c_float) -> c_float;
+        pub fn atanf(n: c_float) -> c_float;
+        pub fn coshf(n: c_float) -> c_float;
+        pub fn sinhf(n: c_float) -> c_float;
+        pub fn tanf(n: c_float) -> c_float;
+        pub fn tanhf(n: c_float) -> c_float;
+    }
+}
+
+// On MSVC these functions aren't defined, so we just define shims which promote
+// everything fo f64, perform the calculation, and then demote back to f32.
+// While not precisely correct should be "correct enough" for now.
+#[cfg(target_env = "msvc")]
+mod shims {
+    use libc::c_float;
+
+    #[inline]
+    pub unsafe fn acosf(n: c_float) -> c_float {
+        f64::acos(n as f64) as c_float
+    }
+
+    #[inline]
+    pub unsafe fn asinf(n: c_float) -> c_float {
+        f64::asin(n as f64) as c_float
+    }
+
+    #[inline]
+    pub unsafe fn atan2f(n: c_float, b: c_float) -> c_float {
+        f64::atan2(n as f64, b as f64) as c_float
+    }
+
+    #[inline]
+    pub unsafe fn atanf(n: c_float) -> c_float {
+        f64::atan(n as f64) as c_float
+    }
+
+    #[inline]
+    pub unsafe fn coshf(n: c_float) -> c_float {
+        f64::cosh(n as f64) as c_float
+    }
+
+    #[inline]
+    pub unsafe fn sinhf(n: c_float) -> c_float {
+        f64::sinh(n as f64) as c_float
+    }
+
+    #[inline]
+    pub unsafe fn tanf(n: c_float) -> c_float {
+        f64::tan(n as f64) as c_float
+    }
+
+    #[inline]
+    pub unsafe fn tanhf(n: c_float) -> c_float {
+        f64::tanh(n as f64) as c_float
+    }
+}
diff --git a/src/libstd/sys/windows/mod.rs b/src/libstd/sys/windows/mod.rs
index e7a9a121b25..0d12ecf8fe3 100644
--- a/src/libstd/sys/windows/mod.rs
+++ b/src/libstd/sys/windows/mod.rs
@@ -17,12 +17,16 @@ use os::windows::ffi::{OsStrExt, OsStringExt};
 use path::PathBuf;
 use time::Duration;
 
+pub use libc::strlen;
+pub use self::rand::hashmap_random_keys;
+
 #[macro_use] pub mod compat;
 
 pub mod args;
 #[cfg(feature = "backtrace")]
 pub mod backtrace;
 pub mod c;
+pub mod cmath;
 pub mod condvar;
 #[cfg(feature = "backtrace")]
 pub mod dynamic_lib;
diff --git a/src/libstd/sys/windows/pipe.rs b/src/libstd/sys/windows/pipe.rs
index 452d720ce59..f3b1185c6ea 100644
--- a/src/libstd/sys/windows/pipe.rs
+++ b/src/libstd/sys/windows/pipe.rs
@@ -15,11 +15,13 @@ use io;
 use mem;
 use path::Path;
 use ptr;
-use rand::{self, Rng};
 use slice;
+use sync::atomic::Ordering::SeqCst;
+use sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT};
 use sys::c;
 use sys::fs::{File, OpenOptions};
 use sys::handle::Handle;
+use sys::hashmap_random_keys;
 
 ////////////////////////////////////////////////////////////////////////////////
 // Anonymous pipes
@@ -71,10 +73,9 @@ pub fn anon_pipe(ours_readable: bool) -> io::Result<Pipes> {
         let mut reject_remote_clients_flag = c::PIPE_REJECT_REMOTE_CLIENTS;
         loop {
             tries += 1;
-            let key: u64 = rand::thread_rng().gen();
             name = format!(r"\\.\pipe\__rust_anonymous_pipe1__.{}.{}",
                            c::GetCurrentProcessId(),
-                           key);
+                           random_number());
             let wide_name = OsStr::new(&name)
                                   .encode_wide()
                                   .chain(Some(0))
@@ -156,6 +157,17 @@ pub fn anon_pipe(ours_readable: bool) -> io::Result<Pipes> {
     }
 }
 
+fn random_number() -> usize {
+    static N: AtomicUsize = ATOMIC_USIZE_INIT;
+    loop {
+        if N.load(SeqCst) != 0 {
+            return N.fetch_add(1, SeqCst)
+        }
+
+        N.store(hashmap_random_keys().0 as usize, SeqCst);
+    }
+}
+
 impl AnonPipe {
     pub fn handle(&self) -> &Handle { &self.inner }
     pub fn into_handle(self) -> Handle { self.inner }
diff --git a/src/libstd/sys/windows/rand.rs b/src/libstd/sys/windows/rand.rs
index f66b0a3bdc3..262323656aa 100644
--- a/src/libstd/sys/windows/rand.rs
+++ b/src/libstd/sys/windows/rand.rs
@@ -8,45 +8,19 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-
 use io;
 use mem;
-use rand::Rng;
 use sys::c;
 
-pub struct OsRng;
-
-impl OsRng {
-    /// Create a new `OsRng`.
-    pub fn new() -> io::Result<OsRng> {
-        Ok(OsRng)
-    }
-}
-
-impl Rng for OsRng {
-    fn next_u32(&mut self) -> u32 {
-        let mut v = [0; 4];
-        self.fill_bytes(&mut v);
-        unsafe { mem::transmute(v) }
-    }
-
-    fn next_u64(&mut self) -> u64 {
-        let mut v = [0; 8];
-        self.fill_bytes(&mut v);
-        unsafe { mem::transmute(v) }
-    }
-
-    fn fill_bytes(&mut self, v: &mut [u8]) {
-        // RtlGenRandom takes an ULONG (u32) for the length so we need to
-        // split up the buffer.
-        for slice in v.chunks_mut(<c::ULONG>::max_value() as usize) {
-            let ret = unsafe {
-                c::RtlGenRandom(slice.as_mut_ptr(), slice.len() as c::ULONG)
-            };
-            if ret == 0 {
-                panic!("couldn't generate random bytes: {}",
-                       io::Error::last_os_error());
-            }
-        }
+pub fn hashmap_random_keys() -> (u64, u64) {
+    let mut v = (0, 0);
+    let ret = unsafe {
+        c::RtlGenRandom(&mut v as *mut _ as *mut u8,
+                        mem::size_of_val(&v) as c::ULONG)
+    };
+    if ret == 0 {
+        panic!("couldn't generate random bytes: {}",
+               io::Error::last_os_error());
     }
+    return v
 }
diff --git a/src/libstd/sys/windows/stdio.rs b/src/libstd/sys/windows/stdio.rs
index b5e5b5760f2..b43df20bddd 100644
--- a/src/libstd/sys/windows/stdio.rs
+++ b/src/libstd/sys/windows/stdio.rs
@@ -218,7 +218,10 @@ fn readconsole_input_control(wakeup_mask: c::ULONG) -> c::CONSOLE_READCONSOLE_CO
 const CTRL_Z: u8 = 0x1A;
 const CTRL_Z_MASK: c::ULONG = 0x4000000; //1 << 0x1A
 
-pub const EBADF_ERR: i32 = ::sys::c::ERROR_INVALID_HANDLE as i32;
+pub fn is_ebadf(err: &io::Error) -> bool {
+    err.raw_os_error() == Some(c::ERROR_INVALID_HANDLE as i32)
+}
+
 // The default buffer capacity is 64k, but apparently windows
 // doesn't like 64k reads on stdin. See #13304 for details, but the
 // idea is that on windows we use a slightly smaller buffer that's
diff --git a/src/libstd/sys/windows/thread.rs b/src/libstd/sys/windows/thread.rs
index c47baaa2434..74786d09285 100644
--- a/src/libstd/sys/windows/thread.rs
+++ b/src/libstd/sys/windows/thread.rs
@@ -52,7 +52,7 @@ impl Thread {
         };
 
         extern "system" fn thread_start(main: *mut c_void) -> c::DWORD {
-            unsafe { start_thread(main); }
+            unsafe { start_thread(main as *mut u8); }
             0
         }
     }