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Auto merge of #27845 - dylanmckay:abstract-pointer-size-away, r=alexcrichton

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This patch rewrites code in several places which assume that the current target has either 32-bit or 64-bit pointers so that it can support arbitrary-width pointers.

It does not completely remove all assumptions of pointer width, but it does reduce them significantly. There is a discussion [here](https://internals.rust-lang.org/t/adding-16-bit-pointer-support/2484/10) about the change.
This commit is contained in:
bors 2015-08-15 19:10:40 +00:00
commit f05b22efb5
9 changed files with 47 additions and 60 deletions
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1
src/liballoc/lib.rs
View file

@ -83,6 +83,7 @@
#![feature(lang_items)]
#![feature(no_std)]
#![feature(nonzero)]
#![feature(num_bits_bytes)]
#![feature(optin_builtin_traits)]
#![feature(placement_in_syntax)]
#![feature(placement_new_protocol)]

10
src/liballoc/raw_vec.rs
View file

@ -15,6 +15,7 @@ use heap;
use super::oom;
use super::boxed::Box;
use core::ops::Drop;
use core;
/// A low-level utility for more ergonomically allocating, reallocating, and deallocating a
/// a buffer of memory on the heap without having to worry about all the corner cases
@ -443,11 +444,8 @@ impl<T> Drop for RawVec<T> {
// user-space. e.g. PAE or x32
#[inline]
#[cfg(target_pointer_width = "64")]
fn alloc_guard(_alloc_size: usize) { }
#[inline]
#[cfg(target_pointer_width = "32")]
fn alloc_guard(alloc_size: usize) {
assert!(alloc_size <= ::core::isize::MAX as usize, "capacity overflow");
if core::usize::BITS < 64 {
assert!(alloc_size <= ::core::isize::MAX as usize, "capacity overflow");
}
}

7
src/libcore/fmt/mod.rs
View file

@ -1340,12 +1340,7 @@ impl<T> Pointer for *const T {
f.flags |= 1 << (FlagV1::SignAwareZeroPad as u32);
if let None = f.width {
// The formats need two extra bytes, for the 0x
if cfg!(target_pointer_width = "32") {
f.width = Some(10);
} else {
f.width = Some(18);
}
f.width = Some((::usize::BITS/4) + 2);
}
}
f.flags |= 1 << (FlagV1::Alternate as u32);

10
src/libcore/hash/mod.rs
View file

@ -144,11 +144,11 @@ pub trait Hasher {
#[inline]
#[stable(feature = "hasher_write", since = "1.3.0")]
fn write_usize(&mut self, i: usize) {
if cfg!(target_pointer_width = "32") {
self.write_u32(i as u32)
} else {
self.write_u64(i as u64)
}
let bytes = unsafe {
::slice::from_raw_parts(&i as *const usize as *const u8,
mem::size_of::<usize>())
};
self.write(bytes);
}
/// Write a single `i8` into this hasher.

4
src/libcore/iter.rs
View file

@ -2236,7 +2236,9 @@ step_impl_signed!(isize i8 i16 i32);
step_impl_unsigned!(u64);
#[cfg(target_pointer_width = "64")]
step_impl_signed!(i64);
#[cfg(target_pointer_width = "32")]
// If the target pointer width is not 64-bits, we
// assume here that it is less than 64-bits.
#[cfg(not(target_pointer_width = "64"))]
step_impl_no_between!(u64 i64);
/// An adapter for stepping range iterators by a custom amount.

15
src/librustc_trans/trans/base.rs
View file

@ -943,11 +943,8 @@ pub fn call_lifetime_end(cx: Block, ptr: ValueRef) {
pub fn call_memcpy(cx: Block, dst: ValueRef, src: ValueRef, n_bytes: ValueRef, align: u32) {
let _icx = push_ctxt("call_memcpy");
let ccx = cx.ccx();
let key = match &ccx.sess().target.target.target_pointer_width[..] {
"32" => "llvm.memcpy.p0i8.p0i8.i32",
"64" => "llvm.memcpy.p0i8.p0i8.i64",
tws => panic!("Unsupported target word size for memcpy: {}", tws),
};
let ptr_width = &ccx.sess().target.target.target_pointer_width[..];
let key = format!("llvm.memcpy.p0i8.p0i8.i{}", ptr_width);
let memcpy = ccx.get_intrinsic(&key);
let src_ptr = PointerCast(cx, src, Type::i8p(ccx));
let dst_ptr = PointerCast(cx, dst, Type::i8p(ccx));
@ -996,12 +993,8 @@ fn memfill<'a, 'tcx>(b: &Builder<'a, 'tcx>, llptr: ValueRef, ty: Ty<'tcx>, byte:
let ccx = b.ccx;
let llty = type_of::type_of(ccx, ty);
let intrinsic_key = match &ccx.sess().target.target.target_pointer_width[..] {
"32" => "llvm.memset.p0i8.i32",
"64" => "llvm.memset.p0i8.i64",
tws => panic!("Unsupported target word size for memset: {}", tws),
};
let ptr_width = &ccx.sess().target.target.target_pointer_width[..];
let intrinsic_key = format!("llvm.memset.p0i8.i{}", ptr_width);
let llintrinsicfn = ccx.get_intrinsic(&intrinsic_key);
let llptr = b.pointercast(llptr, Type::i8(ccx).ptr_to());

18
src/librustc_trans/trans/common.rs
View file

@ -833,10 +833,11 @@ pub fn C_u64(ccx: &CrateContext, i: u64) -> ValueRef {
pub fn C_int<I: AsI64>(ccx: &CrateContext, i: I) -> ValueRef {
let v = i.as_i64();
match machine::llbitsize_of_real(ccx, ccx.int_type()) {
32 => assert!(v < (1<<31) && v >= -(1<<31)),
64 => {},
n => panic!("unsupported target size: {}", n)
let bit_size = machine::llbitsize_of_real(ccx, ccx.int_type());
if bit_size < 64 {
// make sure it doesn't overflow
assert!(v < (1<<(bit_size-1)) && v >= -(1<<(bit_size-1)));
}
C_integral(ccx.int_type(), v as u64, true)
@ -845,10 +846,11 @@ pub fn C_int<I: AsI64>(ccx: &CrateContext, i: I) -> ValueRef {
pub fn C_uint<I: AsU64>(ccx: &CrateContext, i: I) -> ValueRef {
let v = i.as_u64();
match machine::llbitsize_of_real(ccx, ccx.int_type()) {
32 => assert!(v < (1<<32)),
64 => {},
n => panic!("unsupported target size: {}", n)
let bit_size = machine::llbitsize_of_real(ccx, ccx.int_type());
if bit_size < 64 {
// make sure it doesn't overflow
assert!(v < (1<<bit_size));
}
C_integral(ccx.int_type(), v, false)

17
src/librustc_trans/trans/context.rs
View file

@ -560,13 +560,13 @@ impl<'b, 'tcx> CrateContext<'b, 'tcx> {
self.local.builder.b
}
pub fn get_intrinsic(&self, key: & &'static str) -> ValueRef {
pub fn get_intrinsic(&self, key: &str) -> ValueRef {
if let Some(v) = self.intrinsics().borrow().get(key).cloned() {
return v;
}
match declare_intrinsic(self, key) {
Some(v) => return v,
None => panic!()
None => panic!("unknown intrinsic '{}'", key)
}
}
@ -791,10 +791,10 @@ impl<'b, 'tcx> CrateContext<'b, 'tcx> {
}
/// Declare any llvm intrinsics that you might need
fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef> {
fn declare_intrinsic(ccx: &CrateContext, key: &str) -> Option<ValueRef> {
macro_rules! ifn {
($name:expr, fn() -> $ret:expr) => (
if *key == $name {
if key == $name {
let f = declare::declare_cfn(ccx, $name, Type::func(&[], &$ret),
ccx.tcx().mk_nil());
ccx.intrinsics().borrow_mut().insert($name, f.clone());
@ -802,7 +802,7 @@ fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef
}
);
($name:expr, fn($($arg:expr),*) -> $ret:expr) => (
if *key == $name {
if key == $name {
let f = declare::declare_cfn(ccx, $name, Type::func(&[$($arg),*], &$ret),
ccx.tcx().mk_nil());
ccx.intrinsics().borrow_mut().insert($name, f.clone());
@ -824,10 +824,13 @@ fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef
let t_f32 = Type::f32(ccx);
let t_f64 = Type::f64(ccx);
ifn!("llvm.memcpy.p0i8.p0i8.i16", fn(i8p, i8p, t_i16, t_i32, i1) -> void);
ifn!("llvm.memcpy.p0i8.p0i8.i32", fn(i8p, i8p, t_i32, t_i32, i1) -> void);
ifn!("llvm.memcpy.p0i8.p0i8.i64", fn(i8p, i8p, t_i64, t_i32, i1) -> void);
ifn!("llvm.memmove.p0i8.p0i8.i16", fn(i8p, i8p, t_i16, t_i32, i1) -> void);
ifn!("llvm.memmove.p0i8.p0i8.i32", fn(i8p, i8p, t_i32, t_i32, i1) -> void);
ifn!("llvm.memmove.p0i8.p0i8.i64", fn(i8p, i8p, t_i64, t_i32, i1) -> void);
ifn!("llvm.memset.p0i8.i16", fn(i8p, t_i8, t_i16, t_i32, i1) -> void);
ifn!("llvm.memset.p0i8.i32", fn(i8p, t_i8, t_i32, t_i32, i1) -> void);
ifn!("llvm.memset.p0i8.i64", fn(i8p, t_i8, t_i64, t_i32, i1) -> void);
@ -942,7 +945,7 @@ fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef
if unsafe { llvm::LLVMVersionMinor() >= $llvm_version } {
// The `if key == $name` is already in ifn!
ifn!($name, fn($($arg),*) -> void);
} else if *key == $name {
} else if key == $name {
let f = declare::declare_cfn(ccx, stringify!($cname),
Type::func(&[$($arg),*], &void),
ccx.tcx().mk_nil());
@ -965,7 +968,7 @@ fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef
if unsafe { llvm::LLVMVersionMinor() >= $llvm_version } {
// The `if key == $name` is already in ifn!
ifn!($name, fn($($arg),*) -> $ret);
} else if *key == $name {
} else if key == $name {
let f = declare::declare_cfn(ccx, stringify!($cname),
Type::func(&[$($arg),*], &$ret),
ccx.tcx().mk_nil());

25
src/librustc_trans/trans/intrinsic.rs
View file

@ -932,20 +932,15 @@ fn copy_intrinsic<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
let align = C_i32(ccx, type_of::align_of(ccx, tp_ty) as i32);
let size = machine::llsize_of(ccx, lltp_ty);
let int_size = machine::llbitsize_of_real(ccx, ccx.int_type());
let name = if allow_overlap {
if int_size == 32 {
"llvm.memmove.p0i8.p0i8.i32"
} else {
"llvm.memmove.p0i8.p0i8.i64"
}
let operation = if allow_overlap {
"memmove"
} else {
if int_size == 32 {
"llvm.memcpy.p0i8.p0i8.i32"
} else {
"llvm.memcpy.p0i8.p0i8.i64"
}
"memcpy"
};
let name = format!("llvm.{}.p0i8.p0i8.i{}", operation, int_size);
let dst_ptr = PointerCast(bcx, dst, Type::i8p(ccx));
let src_ptr = PointerCast(bcx, src, Type::i8p(ccx));
let llfn = ccx.get_intrinsic(&name);
@ -973,11 +968,9 @@ fn memset_intrinsic<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
let lltp_ty = type_of::type_of(ccx, tp_ty);
let align = C_i32(ccx, type_of::align_of(ccx, tp_ty) as i32);
let size = machine::llsize_of(ccx, lltp_ty);
let name = if machine::llbitsize_of_real(ccx, ccx.int_type()) == 32 {
"llvm.memset.p0i8.i32"
} else {
"llvm.memset.p0i8.i64"
};
let int_size = machine::llbitsize_of_real(ccx, ccx.int_type());
let name = format!("llvm.memset.p0i8.i{}", int_size);
let dst_ptr = PointerCast(bcx, dst, Type::i8p(ccx));
let llfn = ccx.get_intrinsic(&name);