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Change __rust_no_alloc_shim_is_unstable to be a function #141061

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3 changes: 1 addition & 2 deletions .github/workflows/ci.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -225,8 +225,7 @@ jobs:
fi
exit ${STATUS}
env:
AWS_ACCESS_KEY_ID: ${{ env.CACHES_AWS_ACCESS_KEY_ID }}
AWS_SECRET_ACCESS_KEY: ${{ secrets[format('AWS_SECRET_ACCESS_KEY_{0}', env.CACHES_AWS_ACCESS_KEY_ID)] }}
SCCACHE_S3_NO_CREDENTIALS: 1

- name: create github artifacts
run: src/ci/scripts/create-doc-artifacts.sh
Expand Down
40 changes: 28 additions & 12 deletions compiler/rustc_codegen_cranelift/src/allocator.rs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
//! Allocator shim
// Adapted from rustc

use cranelift_frontend::{FunctionBuilder, FunctionBuilderContext};
use rustc_ast::expand::allocator::{
ALLOCATOR_METHODS, AllocatorKind, AllocatorTy, NO_ALLOC_SHIM_IS_UNSTABLE,
alloc_error_handler_name, default_fn_name, global_fn_name,
Expand Down Expand Up @@ -97,16 +98,31 @@ fn codegen_inner(
data.define(Box::new([val]));
module.define_data(data_id, &data).unwrap();

let data_id = module
.declare_data(
&mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE),
Linkage::Export,
false,
false,
)
.unwrap();
let mut data = DataDescription::new();
data.set_align(1);
data.define(Box::new([0]));
module.define_data(data_id, &data).unwrap();
{
let sig = Signature {
call_conv: module.target_config().default_call_conv,
params: vec![],
returns: vec![],
};
let func_id = module
.declare_function(
&mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE),
Linkage::Export,
&sig,
)
.unwrap();

let mut ctx = Context::new();
ctx.func.signature = sig;
let mut func_ctx = FunctionBuilderContext::new();
let mut bcx = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);

let block = bcx.create_block();
bcx.switch_to_block(block);
bcx.ins().return_(&[]);
bcx.seal_all_blocks();
bcx.finalize();

module.define_function(func_id, &mut ctx).unwrap();
}
}
77 changes: 41 additions & 36 deletions compiler/rustc_codegen_gcc/src/allocator.rs
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Expand Up @@ -57,7 +57,7 @@ pub(crate) unsafe fn codegen(
let from_name = mangle_internal_symbol(tcx, &global_fn_name(method.name));
let to_name = mangle_internal_symbol(tcx, &default_fn_name(method.name));

create_wrapper_function(tcx, context, &from_name, &to_name, &types, output);
create_wrapper_function(tcx, context, &from_name, Some(&to_name), &types, output);
}
}

Expand All @@ -66,7 +66,7 @@ pub(crate) unsafe fn codegen(
tcx,
context,
&mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
&mangle_internal_symbol(tcx, alloc_error_handler_name(alloc_error_handler_kind)),
Some(&mangle_internal_symbol(tcx, alloc_error_handler_name(alloc_error_handler_kind))),
&[usize, usize],
None,
);
Expand All @@ -81,21 +81,21 @@ pub(crate) unsafe fn codegen(
let value = context.new_rvalue_from_int(i8, value as i32);
global.global_set_initializer_rvalue(value);

let name = mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE);
let global = context.new_global(None, GlobalKind::Exported, i8, name);
#[cfg(feature = "master")]
global.add_attribute(VarAttribute::Visibility(symbol_visibility_to_gcc(
tcx.sess.default_visibility(),
)));
let value = context.new_rvalue_from_int(i8, 0);
global.global_set_initializer_rvalue(value);
create_wrapper_function(
tcx,
context,
&mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE),
None,
&[],
None,
);
}

fn create_wrapper_function(
tcx: TyCtxt<'_>,
context: &Context<'_>,
from_name: &str,
to_name: &str,
to_name: Option<&str>,
types: &[Type<'_>],
output: Option<Type<'_>>,
) {
Expand Down Expand Up @@ -124,34 +124,39 @@ fn create_wrapper_function(
// TODO(antoyo): emit unwind tables.
}

let args: Vec<_> = types
.iter()
.enumerate()
.map(|(index, typ)| context.new_parameter(None, *typ, format!("param{}", index)))
.collect();
let callee = context.new_function(
None,
FunctionType::Extern,
output.unwrap_or(void),
&args,
to_name,
false,
);
#[cfg(feature = "master")]
callee.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Hidden));

let block = func.new_block("entry");

let args = args
.iter()
.enumerate()
.map(|(i, _)| func.get_param(i as i32).to_rvalue())
.collect::<Vec<_>>();
let ret = context.new_call(None, callee, &args);
//llvm::LLVMSetTailCall(ret, True);
if output.is_some() {
block.end_with_return(None, ret);
if let Some(to_name) = to_name {
let args: Vec<_> = types
.iter()
.enumerate()
.map(|(index, typ)| context.new_parameter(None, *typ, format!("param{}", index)))
.collect();
let callee = context.new_function(
None,
FunctionType::Extern,
output.unwrap_or(void),
&args,
to_name,
false,
);
#[cfg(feature = "master")]
callee.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Hidden));

let args = args
.iter()
.enumerate()
.map(|(i, _)| func.get_param(i as i32).to_rvalue())
.collect::<Vec<_>>();
let ret = context.new_call(None, callee, &args);
//llvm::LLVMSetTailCall(ret, True);
if output.is_some() {
block.end_with_return(None, ret);
} else {
block.end_with_void_return(None);
}
} else {
assert!(output.is_none());
block.end_with_void_return(None);
}

Expand Down
74 changes: 42 additions & 32 deletions compiler/rustc_codegen_llvm/src/allocator.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,7 @@ pub(crate) unsafe fn codegen(
let from_name = mangle_internal_symbol(tcx, &global_fn_name(method.name));
let to_name = mangle_internal_symbol(tcx, &default_fn_name(method.name));

create_wrapper_function(tcx, &cx, &from_name, &to_name, &args, output, false);
create_wrapper_function(tcx, &cx, &from_name, Some(&to_name), &args, output, false);
}
}

Expand All @@ -66,7 +66,7 @@ pub(crate) unsafe fn codegen(
tcx,
&cx,
&mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
&mangle_internal_symbol(tcx, alloc_error_handler_name(alloc_error_handler_kind)),
Some(&mangle_internal_symbol(tcx, alloc_error_handler_name(alloc_error_handler_kind))),
&[usize, usize], // size, align
None,
true,
Expand All @@ -81,11 +81,16 @@ pub(crate) unsafe fn codegen(
let llval = llvm::LLVMConstInt(i8, val as u64, False);
llvm::set_initializer(ll_g, llval);

let name = mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE);
let ll_g = cx.declare_global(&name, i8);
llvm::set_visibility(ll_g, llvm::Visibility::from_generic(tcx.sess.default_visibility()));
let llval = llvm::LLVMConstInt(i8, 0, False);
llvm::set_initializer(ll_g, llval);
// __rust_no_alloc_shim_is_unstable
create_wrapper_function(
tcx,
&cx,
&mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE),
None,
&[],
None,
false,
);
}

if tcx.sess.opts.debuginfo != DebugInfo::None {
Expand All @@ -99,7 +104,7 @@ fn create_wrapper_function(
tcx: TyCtxt<'_>,
cx: &SimpleCx<'_>,
from_name: &str,
to_name: &str,
to_name: Option<&str>,
args: &[&Type],
output: Option<&Type>,
no_return: bool,
Expand Down Expand Up @@ -128,33 +133,38 @@ fn create_wrapper_function(
attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[uwtable]);
}

let callee = declare_simple_fn(
&cx,
to_name,
llvm::CallConv::CCallConv,
llvm::UnnamedAddr::Global,
llvm::Visibility::Hidden,
ty,
);
if let Some(no_return) = no_return {
// -> ! DIFlagNoReturn
attributes::apply_to_llfn(callee, llvm::AttributePlace::Function, &[no_return]);
}
llvm::set_visibility(callee, llvm::Visibility::Hidden);

let llbb = unsafe { llvm::LLVMAppendBasicBlockInContext(cx.llcx, llfn, c"entry".as_ptr()) };

let mut bx = SBuilder::build(&cx, llbb);
let args = args
.iter()
.enumerate()
.map(|(i, _)| llvm::get_param(llfn, i as c_uint))
.collect::<Vec<_>>();
let ret = bx.call(ty, callee, &args, None);
llvm::LLVMSetTailCall(ret, True);
if output.is_some() {
bx.ret(ret);

if let Some(to_name) = to_name {
let callee = declare_simple_fn(
&cx,
to_name,
llvm::CallConv::CCallConv,
llvm::UnnamedAddr::Global,
llvm::Visibility::Hidden,
ty,
);
if let Some(no_return) = no_return {
// -> ! DIFlagNoReturn
attributes::apply_to_llfn(callee, llvm::AttributePlace::Function, &[no_return]);
}
llvm::set_visibility(callee, llvm::Visibility::Hidden);

let args = args
.iter()
.enumerate()
.map(|(i, _)| llvm::get_param(llfn, i as c_uint))
.collect::<Vec<_>>();
let ret = bx.call(ty, callee, &args, None);
llvm::LLVMSetTailCall(ret, True);
if output.is_some() {
bx.ret(ret);
} else {
bx.ret_void()
}
} else {
assert!(output.is_none());
bx.ret_void()
}
}
7 changes: 1 addition & 6 deletions compiler/rustc_codegen_llvm/src/consts.rs
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Expand Up @@ -364,12 +364,7 @@ impl<'ll> CodegenCx<'ll, '_> {

if !def_id.is_local() {
let needs_dll_storage_attr = self.use_dll_storage_attrs
// If the symbol is a foreign item, then don't automatically apply DLLImport, as
// we'll rely on the #[link] attribute instead. BUT, if this is an internal symbol
// then it may be generated by the compiler in some crate, so we do need to apply
// DLLImport when linking with the MSVC linker.
&& (!self.tcx.is_foreign_item(def_id)
|| (self.sess().target.is_like_msvc && fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL)))
&& !self.tcx.is_foreign_item(def_id)
// Local definitions can never be imported, so we must not apply
// the DLLImport annotation.
&& !dso_local
Expand Down
14 changes: 1 addition & 13 deletions compiler/rustc_codegen_ssa/src/back/symbol_export.rs
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Expand Up @@ -219,6 +219,7 @@ fn exported_symbols_provider_local<'tcx>(
.chain([
mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
mangle_internal_symbol(tcx, OomStrategy::SYMBOL),
mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE),
])
{
let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, &symbol_name));
Expand All @@ -232,19 +233,6 @@ fn exported_symbols_provider_local<'tcx>(
},
));
}

let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(
tcx,
&mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE),
));
symbols.push((
exported_symbol,
SymbolExportInfo {
level: SymbolExportLevel::Rust,
kind: SymbolExportKind::Data,
used: false,
},
))
}

if tcx.sess.instrument_coverage() || tcx.sess.opts.cg.profile_generate.enabled() {
Expand Down
14 changes: 1 addition & 13 deletions compiler/rustc_target/src/spec/base/msvc.rs
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Expand Up @@ -5,19 +5,7 @@ use crate::spec::{BinaryFormat, DebuginfoKind, LinkerFlavor, Lld, SplitDebuginfo
pub(crate) fn opts() -> TargetOptions {
// Suppress the verbose logo and authorship debugging output, which would needlessly
// clog any log files.
let pre_link_args = TargetOptions::link_args(
LinkerFlavor::Msvc(Lld::No),
&[
"/NOLOGO",
// "Symbol is marked as dllimport, but defined in an object file"
// Harmless warning that flags a potential performance improvement: marking a symbol as
// dllimport indirects usage via the `__imp_` symbol, which isn't required if the symbol
// is in the current binary. This is tripped by __rust_no_alloc_shim_is_unstable as it
// is generated by the compiler, but marked as a foreign item (hence the dllimport) in
// the standard library.
"/IGNORE:4286",
],
);
let pre_link_args = TargetOptions::link_args(LinkerFlavor::Msvc(Lld::No), &["/NOLOGO"]);

TargetOptions {
linker_flavor: LinkerFlavor::Msvc(Lld::No),
Expand Down
12 changes: 12 additions & 0 deletions library/alloc/src/alloc.rs
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Expand Up @@ -31,8 +31,14 @@ unsafe extern "Rust" {
#[rustc_std_internal_symbol]
fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8;

#[rustc_nounwind]
#[rustc_std_internal_symbol]
#[cfg(not(bootstrap))]
fn __rust_no_alloc_shim_is_unstable();
#[rustc_std_internal_symbol]
#[cfg(bootstrap)]
static __rust_no_alloc_shim_is_unstable: u8;

}

/// The global memory allocator.
Expand Down Expand Up @@ -88,7 +94,10 @@ pub unsafe fn alloc(layout: Layout) -> *mut u8 {
unsafe {
// Make sure we don't accidentally allow omitting the allocator shim in
// stable code until it is actually stabilized.
#[cfg(bootstrap)]
core::ptr::read_volatile(&__rust_no_alloc_shim_is_unstable);
#[cfg(not(bootstrap))]
__rust_no_alloc_shim_is_unstable();

__rust_alloc(layout.size(), layout.align())
}
Expand Down Expand Up @@ -171,7 +180,10 @@ pub unsafe fn alloc_zeroed(layout: Layout) -> *mut u8 {
unsafe {
// Make sure we don't accidentally allow omitting the allocator shim in
// stable code until it is actually stabilized.
#[cfg(bootstrap)]
core::ptr::read_volatile(&__rust_no_alloc_shim_is_unstable);
#[cfg(not(bootstrap))]
__rust_no_alloc_shim_is_unstable();

__rust_alloc_zeroed(layout.size(), layout.align())
}
Expand Down
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