rust/src/librustc_codegen_llvm/allocator.rs
2019-06-14 18:58:23 +03:00

94 lines
3.8 KiB
Rust

use std::ffi::CString;
use crate::attributes;
use libc::c_uint;
use rustc::middle::allocator::AllocatorKind;
use rustc::ty::TyCtxt;
use rustc_allocator::{ALLOCATOR_METHODS, AllocatorTy};
use crate::ModuleLlvm;
use crate::llvm::{self, False, True};
pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, mods: &mut ModuleLlvm, kind: AllocatorKind) {
let llcx = &*mods.llcx;
let llmod = mods.llmod();
let usize = match &tcx.sess.target.target.target_pointer_width[..] {
"16" => llvm::LLVMInt16TypeInContext(llcx),
"32" => llvm::LLVMInt32TypeInContext(llcx),
"64" => llvm::LLVMInt64TypeInContext(llcx),
tws => bug!("Unsupported target word size for int: {}", tws),
};
let i8 = llvm::LLVMInt8TypeInContext(llcx);
let i8p = llvm::LLVMPointerType(i8, 0);
let void = llvm::LLVMVoidTypeInContext(llcx);
for method in ALLOCATOR_METHODS {
let mut args = Vec::with_capacity(method.inputs.len());
for ty in method.inputs.iter() {
match *ty {
AllocatorTy::Layout => {
args.push(usize); // size
args.push(usize); // align
}
AllocatorTy::Ptr => args.push(i8p),
AllocatorTy::Usize => args.push(usize),
AllocatorTy::ResultPtr |
AllocatorTy::Unit => panic!("invalid allocator arg"),
}
}
let output = match method.output {
AllocatorTy::ResultPtr => Some(i8p),
AllocatorTy::Unit => None,
AllocatorTy::Layout |
AllocatorTy::Usize |
AllocatorTy::Ptr => panic!("invalid allocator output"),
};
let ty = llvm::LLVMFunctionType(output.unwrap_or(void),
args.as_ptr(),
args.len() as c_uint,
False);
let name = CString::new(format!("__rust_{}", method.name)).unwrap();
let llfn = llvm::LLVMRustGetOrInsertFunction(llmod,
name.as_ptr(),
ty);
if tcx.sess.target.target.options.default_hidden_visibility {
llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
}
if tcx.sess.target.target.options.requires_uwtable {
attributes::emit_uwtable(llfn, true);
}
let callee = CString::new(kind.fn_name(method.name)).unwrap();
let callee = llvm::LLVMRustGetOrInsertFunction(llmod,
callee.as_ptr(),
ty);
llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden);
let llbb = llvm::LLVMAppendBasicBlockInContext(llcx,
llfn,
"entry\0".as_ptr() as *const _);
let llbuilder = llvm::LLVMCreateBuilderInContext(llcx);
llvm::LLVMPositionBuilderAtEnd(llbuilder, llbb);
let args = args.iter().enumerate().map(|(i, _)| {
llvm::LLVMGetParam(llfn, i as c_uint)
}).collect::<Vec<_>>();
let ret = llvm::LLVMRustBuildCall(llbuilder,
callee,
args.as_ptr(),
args.len() as c_uint,
None,
"\0".as_ptr() as *const _);
llvm::LLVMSetTailCall(ret, True);
if output.is_some() {
llvm::LLVMBuildRet(llbuilder, ret);
} else {
llvm::LLVMBuildRetVoid(llbuilder);
}
llvm::LLVMDisposeBuilder(llbuilder);
}
}