80 lines
2.9 KiB
Rust
80 lines
2.9 KiB
Rust
// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Information concerning the machine representation of various types.
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#![allow(non_camel_case_types)]
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use llvm::{self, ValueRef};
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use common::*;
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use type_::Type;
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pub type llbits = u64;
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pub type llsize = u64;
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pub type llalign = u32;
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// ______________________________________________________________________
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// compute sizeof / alignof
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// Returns the number of bytes between successive elements of type T in an
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// array of T. This is the "ABI" size. It includes any ABI-mandated padding.
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pub fn llsize_of_alloc(cx: &CrateContext, ty: Type) -> llsize {
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unsafe {
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return llvm::LLVMABISizeOfType(cx.td(), ty.to_ref());
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}
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}
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/// Returns the "real" size of the type in bits.
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pub fn llbitsize_of_real(cx: &CrateContext, ty: Type) -> llbits {
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unsafe {
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llvm::LLVMSizeOfTypeInBits(cx.td(), ty.to_ref())
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}
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}
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/// Returns the size of the type as an LLVM constant integer value.
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pub fn llsize_of(cx: &CrateContext, ty: Type) -> ValueRef {
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// Once upon a time, this called LLVMSizeOf, which does a
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// getelementptr(1) on a null pointer and casts to an int, in
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// order to obtain the type size as a value without requiring the
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// target data layout. But we have the target data layout, so
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// there's no need for that contrivance. The instruction
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// selection DAG generator would flatten that GEP(1) node into a
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// constant of the type's alloc size, so let's save it some work.
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return C_uint(cx, llsize_of_alloc(cx, ty));
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}
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// Returns the preferred alignment of the given type for the current target.
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// The preferred alignment may be larger than the alignment used when
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// packing the type into structs. This will be used for things like
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// allocations inside a stack frame, which LLVM has a free hand in.
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pub fn llalign_of_pref(cx: &CrateContext, ty: Type) -> llalign {
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unsafe {
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return llvm::LLVMPreferredAlignmentOfType(cx.td(), ty.to_ref());
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}
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}
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// Returns the minimum alignment of a type required by the platform.
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// This is the alignment that will be used for struct fields, arrays,
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// and similar ABI-mandated things.
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pub fn llalign_of_min(cx: &CrateContext, ty: Type) -> llalign {
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unsafe {
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return llvm::LLVMABIAlignmentOfType(cx.td(), ty.to_ref());
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}
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}
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pub fn llelement_offset(cx: &CrateContext, struct_ty: Type, element: usize) -> u64 {
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unsafe {
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return llvm::LLVMOffsetOfElement(cx.td(),
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struct_ty.to_ref(),
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element as u32);
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}
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}
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