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 lib;
use middle::trans::build::*;
use middle::trans::callee;
use middle::trans::common::*;
use middle::trans::cleanup;
use middle::trans::cleanup::CleanupMethods;
use middle::trans::expr;
use middle::trans::type_of;
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use middle::trans::type_::Type;
use std::c_str::ToCStr;
use std::string::String;
use syntax::ast;
// Take an inline assembly expression and splat it out via LLVM
pub fn trans_inline_asm<'a>(bcx: &'a Block<'a>, ia: &ast::InlineAsm)
-> &'a Block<'a> {
let fcx = bcx.fcx;
let mut bcx = bcx;
let mut constraints = Vec::new();
let mut output_types = Vec::new();
let temp_scope = fcx.push_custom_cleanup_scope();
// Prepare the output operands
let outputs = ia.outputs.iter().map(|&(ref c, out)| {
constraints.push((*c).clone());
let out_datum = unpack_datum!(bcx, expr::trans(bcx, out));
output_types.push(type_of::type_of(bcx.ccx(), out_datum.ty));
out_datum.val
}).collect::<Vec<_>>();
// Now the input operands
let inputs = ia.inputs.iter().map(|&(ref c, input)| {
constraints.push((*c).clone());
let in_datum = unpack_datum!(bcx, expr::trans(bcx, input));
unpack_result!(bcx, {
callee::trans_arg_datum(bcx,
expr_ty(bcx, input),
in_datum,
cleanup::CustomScope(temp_scope),
callee::DontAutorefArg)
})
}).collect::<Vec<_>>();
// no failure occurred preparing operands, no need to cleanup
fcx.pop_custom_cleanup_scope(temp_scope);
let mut constraints =
String::from_str(constraints.iter()
.map(|s| s.get().to_strbuf())
.collect::<Vec<String>>()
.connect(",")
.as_slice());
let mut clobbers = getClobbers();
if !ia.clobbers.get().is_empty() && !clobbers.is_empty() {
clobbers = format_strbuf!("{},{}", ia.clobbers.get(), clobbers);
} else {
clobbers.push_str(ia.clobbers.get());
}
// Add the clobbers to our constraints list
if clobbers.len() != 0 && constraints.len() != 0 {
constraints.push_char(',');
constraints.push_str(clobbers.as_slice());
} else {
constraints.push_str(clobbers.as_slice());
}
debug!("Asm Constraints: {:?}", constraints.as_slice());
let num_outputs = outputs.len();
// Depending on how many outputs we have, the return type is different
let output_type = if num_outputs == 0 {
Type::void(bcx.ccx())
} else if num_outputs == 1 {
*output_types.get(0)
} else {
Type::struct_(bcx.ccx(), output_types.as_slice(), false)
};
let dialect = match ia.dialect {
ast::AsmAtt => lib::llvm::AD_ATT,
ast::AsmIntel => lib::llvm::AD_Intel
};
let r = ia.asm.get().with_c_str(|a| {
constraints.as_slice().with_c_str(|c| {
InlineAsmCall(bcx,
a,
c,
inputs.as_slice(),
output_type,
ia.volatile,
ia.alignstack,
dialect)
})
});
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// Again, based on how many outputs we have
if num_outputs == 1 {
Store(bcx, r, *outputs.get(0));
} else {
for (i, o) in outputs.iter().enumerate() {
let v = ExtractValue(bcx, r, i);
Store(bcx, v, *o);
}
}
return bcx;
}
// Default per-arch clobbers
// Basically what clang does
#[cfg(target_arch = "arm")]
#[cfg(target_arch = "mips")]
fn getClobbers() -> String {
"".to_strbuf()
}
#[cfg(target_arch = "x86")]
#[cfg(target_arch = "x86_64")]
fn getClobbers() -> String {
"~{dirflag},~{fpsr},~{flags}".to_strbuf()
}