rust/src/librustc/middle/trans/asm.rs

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// Copyright 2012-2013 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.
/*!
# Translation of inline assembly.
*/
use core::prelude::*;
use lib;
use middle::trans::build::*;
use middle::trans::callee;
use middle::trans::common::*;
use middle::ty;
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use middle::trans::type_::Type;
use core::str;
use syntax::ast;
// Take an inline assembly expression and splat it out via LLVM
pub fn trans_inline_asm(bcx: block, ia: &ast::inline_asm) -> block {
let mut bcx = bcx;
let mut constraints = ~[];
let mut cleanups = ~[];
let mut aoutputs = ~[];
// Prepare the output operands
let outputs = do ia.outputs.map |&(c, out)| {
constraints.push(c);
aoutputs.push(unpack_result!(bcx, {
callee::trans_arg_expr(bcx,
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expr_ty(bcx, out),
ty::ByCopy,
out,
&mut cleanups,
None,
callee::DontAutorefArg)
}));
let e = match out.node {
ast::expr_addr_of(_, e) => e,
_ => fail!("Expression must be addr of")
};
unpack_result!(bcx, {
callee::trans_arg_expr(bcx,
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expr_ty(bcx, e),
ty::ByCopy,
e,
&mut cleanups,
None,
callee::DontAutorefArg)
})
};
for cleanups.each |c| {
revoke_clean(bcx, *c);
}
cleanups.clear();
// Now the input operands
let inputs = do ia.inputs.map |&(c, in)| {
constraints.push(c);
unpack_result!(bcx, {
callee::trans_arg_expr(bcx,
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expr_ty(bcx, in),
ty::ByCopy,
in,
&mut cleanups,
None,
callee::DontAutorefArg)
})
};
for cleanups.each |c| {
revoke_clean(bcx, *c);
}
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let mut constraints = constraints.connect(",");
let mut clobbers = getClobbers();
if !ia.clobbers.is_empty() && !clobbers.is_empty() {
clobbers = fmt!("%s,%s", ia.clobbers, clobbers);
} else {
clobbers += ia.clobbers;
};
// Add the clobbers to our constraints list
if !clobbers.is_empty() && !constraints.is_empty() {
constraints += ",";
constraints += clobbers;
} else {
constraints += clobbers;
}
debug!("Asm Constraints: %?", constraints);
let numOutputs = outputs.len();
// Depending on how many outputs we have, the return type is different
let output = if numOutputs == 0 {
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Type::void()
} else if numOutputs == 1 {
val_ty(outputs[0])
} else {
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Type::struct_(outputs.map(|o| val_ty(*o)), false)
};
let dialect = match ia.dialect {
ast::asm_att => lib::llvm::AD_ATT,
ast::asm_intel => lib::llvm::AD_Intel
};
let r = do str::as_c_str(ia.asm) |a| {
do str::as_c_str(constraints) |c| {
InlineAsmCall(bcx, a, c, inputs, output, ia.volatile, ia.alignstack, dialect)
}
};
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// Again, based on how many outputs we have
if numOutputs == 1 {
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let op = PointerCast(bcx, aoutputs[0], val_ty(outputs[0]).ptr_to());
Store(bcx, r, op);
} else {
for aoutputs.iter().enumerate().advance |(i, o)| {
let v = ExtractValue(bcx, r, i);
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let op = PointerCast(bcx, *o, val_ty(outputs[i]).ptr_to());
Store(bcx, v, op);
}
}
return bcx;
}
// Default per-arch clobbers
// Basically what clang does
#[cfg(target_arch = "arm")]
#[cfg(target_arch = "mips")]
fn getClobbers() -> ~str {
~""
}
#[cfg(target_arch = "x86")]
#[cfg(target_arch = "x86_64")]
fn getClobbers() -> ~str {
~"~{dirflag},~{fpsr},~{flags}"
}