From 063ddbe33b71717a10419de2b1fce6b81848466a Mon Sep 17 00:00:00 2001 From: DianQK Date: Sat, 15 Jul 2023 16:09:04 +0800 Subject: [PATCH] Add the `no-builtins` attribute to functions when `no_builtins` is applied at the crate level. When `no_builtins` is applied at the crate level, we should add the `no-builtins` attribute to each function to ensure it takes effect in LTO. --- compiler/rustc_codegen_llvm/src/attributes.rs | 4 ++++ .../rustc_codegen_ssa/src/codegen_attrs.rs | 10 +++++++- .../src/middle/codegen_fn_attrs.rs | 2 ++ tests/codegen/no_builtins-at-crate.rs | 23 +++++++++++++++++++ tests/run-make/no-builtins-attribute/Makefile | 9 ++++++++ .../no-builtins-attribute/filecheck.main.txt | 5 ++++ tests/run-make/no-builtins-attribute/main.rs | 10 ++++++++ .../no-builtins-attribute/no_builtins.rs | 5 ++++ 8 files changed, 67 insertions(+), 1 deletion(-) create mode 100644 tests/codegen/no_builtins-at-crate.rs create mode 100644 tests/run-make/no-builtins-attribute/Makefile create mode 100644 tests/run-make/no-builtins-attribute/filecheck.main.txt create mode 100644 tests/run-make/no-builtins-attribute/main.rs create mode 100644 tests/run-make/no-builtins-attribute/no_builtins.rs diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs index 39275272e4226..4c69b9503a2cf 100644 --- a/compiler/rustc_codegen_llvm/src/attributes.rs +++ b/compiler/rustc_codegen_llvm/src/attributes.rs @@ -335,6 +335,10 @@ pub fn from_fn_attrs<'ll, 'tcx>( to_add.extend(probestack_attr(cx)); to_add.extend(stackprotector_attr(cx)); + if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NO_BUILTINS) { + to_add.push(llvm::CreateAttrString(cx.llcx, "no-builtins")); + } + if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::COLD) { to_add.push(AttributeKind::Cold.create_attr(cx.llcx)); } diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs index d6c2301276262..0c7b8a7961281 100644 --- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs +++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs @@ -1,4 +1,4 @@ -use rustc_ast::{ast, MetaItemKind, NestedMetaItem}; +use rustc_ast::{ast, attr, MetaItemKind, NestedMetaItem}; use rustc_attr::{list_contains_name, InlineAttr, InstructionSetAttr, OptimizeAttr}; use rustc_errors::struct_span_err; use rustc_hir as hir; @@ -60,6 +60,14 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs { codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER; } + // When `no_builtins` is applied at the crate level, we should add the + // `no-builtins` attribute to each function to ensure it takes effect in LTO. + let crate_attrs = tcx.hir().attrs(rustc_hir::CRATE_HIR_ID); + let no_builtins = attr::contains_name(crate_attrs, sym::no_builtins); + if no_builtins { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_BUILTINS; + } + let supported_target_features = tcx.supported_target_features(LOCAL_CRATE); let mut inline_span = None; diff --git a/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs b/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs index c4601a1fb4189..02fd6ed7ba6ba 100644 --- a/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs +++ b/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs @@ -100,6 +100,8 @@ bitflags! { const REALLOCATOR = 1 << 18; /// `#[rustc_allocator_zeroed]`: a hint to LLVM that the function only allocates zeroed memory. const ALLOCATOR_ZEROED = 1 << 19; + /// `#[no_builtins]`: indicates that disable implicit builtin knowledge of functions for the function. + const NO_BUILTINS = 1 << 20; } } diff --git a/tests/codegen/no_builtins-at-crate.rs b/tests/codegen/no_builtins-at-crate.rs new file mode 100644 index 0000000000000..bb64159649144 --- /dev/null +++ b/tests/codegen/no_builtins-at-crate.rs @@ -0,0 +1,23 @@ +// compile-flags: -C opt-level=1 + +#![no_builtins] +#![crate_type = "lib"] + +// CHECK: define void @__aeabi_memcpy +// CHECK-SAME: #0 +#[no_mangle] +pub unsafe extern "C" fn __aeabi_memcpy(dest: *mut u8, src: *const u8, size: usize) { + // CHECK: call + // CHECK-SAME: @memcpy( + memcpy(dest, src, size); +} + +// CHECK: declare +// CHECK-SAME: @memcpy +// CHECK-SAME: #0 +extern "C" { + pub fn memcpy(dest: *mut u8, src: *const u8, n: usize) -> *mut u8; +} + +// CHECK: attributes #0 +// CHECK-SAME: "no-builtins" diff --git a/tests/run-make/no-builtins-attribute/Makefile b/tests/run-make/no-builtins-attribute/Makefile new file mode 100644 index 0000000000000..0ce95facaea48 --- /dev/null +++ b/tests/run-make/no-builtins-attribute/Makefile @@ -0,0 +1,9 @@ +include ../tools.mk + +# We want to check if `no-builtins` is also added to the function declarations in the used crate. + +all: + $(RUSTC) no_builtins.rs --emit=link + $(RUSTC) main.rs --emit=llvm-ir + + cat "$(TMPDIR)"/main.ll | "$(LLVM_FILECHECK)" filecheck.main.txt diff --git a/tests/run-make/no-builtins-attribute/filecheck.main.txt b/tests/run-make/no-builtins-attribute/filecheck.main.txt new file mode 100644 index 0000000000000..ecd650bdca804 --- /dev/null +++ b/tests/run-make/no-builtins-attribute/filecheck.main.txt @@ -0,0 +1,5 @@ +CHECK: declare void @foo() +CHECK-SAME: #[[ATTR_3:[0-9]+]] + +CHECK: attributes #[[ATTR_3]] +CHECK-SAME: no-builtins diff --git a/tests/run-make/no-builtins-attribute/main.rs b/tests/run-make/no-builtins-attribute/main.rs new file mode 100644 index 0000000000000..77754b37e3184 --- /dev/null +++ b/tests/run-make/no-builtins-attribute/main.rs @@ -0,0 +1,10 @@ +extern crate no_builtins; + +#[no_mangle] +fn call_foo() { + no_builtins::foo(); +} + +fn main() { + call_foo(); +} diff --git a/tests/run-make/no-builtins-attribute/no_builtins.rs b/tests/run-make/no-builtins-attribute/no_builtins.rs new file mode 100644 index 0000000000000..8ca862d2f7773 --- /dev/null +++ b/tests/run-make/no-builtins-attribute/no_builtins.rs @@ -0,0 +1,5 @@ +#![crate_type = "lib"] +#![no_builtins] + +#[no_mangle] +pub fn foo() {}