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rustc: Use link_section, not wasm_custom_section

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This commit transitions definitions of custom sections on the wasm target from
the unstable `#[wasm_custom_section]` attribute to the
already-stable-for-other-targets `#[link_section]` attribute. Mostly the same
restrictions apply as before, except that this now applies only to statics.

Closes #51088
This commit is contained in:
Alex Crichton 2018-07-13 11:30:47 -07:00
parent 50702b2838
commit b7ef674832
26 changed files with 148 additions and 329 deletions
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66
src/librustc_codegen_llvm/base.rs
View file

@ -33,7 +33,6 @@ use back::link;
use back::write::{self, OngoingCodegen, create_target_machine};
use llvm::{ContextRef, ModuleRef, ValueRef, Vector, get_param};
use llvm;
use libc::c_uint;
use metadata;
use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
use rustc::middle::lang_items::StartFnLangItem;
@ -87,8 +86,7 @@ use std::sync::mpsc;
use syntax_pos::Span;
use syntax_pos::symbol::InternedString;
use syntax::attr;
use rustc::hir;
use syntax::ast;
use rustc::hir::{self, CodegenFnAttrs};
use mir::operand::OperandValue;
@ -513,17 +511,14 @@ pub fn codegen_instance<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>, instance: Instance<'
mir::codegen_mir(cx, lldecl, &mir, instance, sig);
}
pub fn set_link_section(cx: &CodegenCx,
llval: ValueRef,
attrs: &[ast::Attribute]) {
if let Some(sect) = attr::first_attr_value_str_by_name(attrs, "link_section") {
if contains_null(&sect.as_str()) {
cx.sess().fatal(&format!("Illegal null byte in link_section value: `{}`", &sect));
}
unsafe {
let buf = CString::new(sect.as_str().as_bytes()).unwrap();
llvm::LLVMSetSection(llval, buf.as_ptr());
}
pub fn set_link_section(llval: ValueRef, attrs: &CodegenFnAttrs) {
let sect = match attrs.link_section {
Some(name) => name,
None => return,
};
unsafe {
let buf = CString::new(sect.as_str().as_bytes()).unwrap();
llvm::LLVMSetSection(llval, buf.as_ptr());
}
}
@ -613,10 +608,6 @@ fn maybe_create_entry_wrapper(cx: &CodegenCx) {
}
}
fn contains_null(s: &str) -> bool {
s.bytes().any(|b| b == 0)
}
fn write_metadata<'a, 'gcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>,
llmod_id: &str,
link_meta: &LinkMeta)
@ -1369,42 +1360,3 @@ mod temp_stable_hash_impls {
}
}
}
pub fn define_custom_section(cx: &CodegenCx, def_id: DefId) {
use rustc::mir::interpret::GlobalId;
assert!(cx.tcx.sess.opts.target_triple.triple().starts_with("wasm32"));
info!("loading wasm section {:?}", def_id);
let section = cx.tcx.codegen_fn_attrs(def_id).wasm_custom_section.unwrap();
let instance = ty::Instance::mono(cx.tcx, def_id);
let cid = GlobalId {
instance,
promoted: None
};
let param_env = ty::ParamEnv::reveal_all();
let val = cx.tcx.const_eval(param_env.and(cid)).unwrap();
let alloc = cx.tcx.const_value_to_allocation(val);
unsafe {
let section = llvm::LLVMMDStringInContext(
cx.llcx,
section.as_str().as_ptr() as *const _,
section.as_str().len() as c_uint,
);
let alloc = llvm::LLVMMDStringInContext(
cx.llcx,
alloc.bytes.as_ptr() as *const _,
alloc.bytes.len() as c_uint,
);
let data = [section, alloc];
let meta = llvm::LLVMMDNodeInContext(cx.llcx, data.as_ptr(), 2);
llvm::LLVMAddNamedMetadataOperand(
cx.llmod,
"wasm.custom_sections\0".as_ptr() as *const _,
meta,
);
}
}