rust/0001-Set-more-llvm-function...

187 lines
7.8 KiB
Diff

From 4b95b1a4fd035a73998dc21b265ce4594e35f8ae Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Thu, 16 Aug 2018 13:19:04 -0700
Subject: [PATCH] Set more llvm function attributes for __rust_try
This shim is generated elsewhere in the compiler so this commit adds support to
ensure it goes through similar paths as the rest of the compiler to set llvm
function attributes like target features.
cc #53372
---
src/librustc_codegen_llvm/attributes.rs | 52 +++++++++++++++++++------
src/librustc_codegen_llvm/base.rs | 21 ----------
src/librustc_codegen_llvm/callee.rs | 2 +-
src/librustc_codegen_llvm/intrinsic.rs | 2 +
src/librustc_codegen_llvm/mono_item.rs | 2 +-
5 files changed, 44 insertions(+), 35 deletions(-)
diff --git a/src/librustc_codegen_llvm/attributes.rs b/src/librustc_codegen_llvm/attributes.rs
index 3b5f927d52f0..2a79ce2f2285 100644
--- a/src/librustc_codegen_llvm/attributes.rs
+++ b/src/librustc_codegen_llvm/attributes.rs
@@ -11,7 +11,7 @@
use std::ffi::{CStr, CString};
-use rustc::hir::CodegenFnAttrFlags;
+use rustc::hir::{CodegenFnAttrFlags, CodegenFnAttrs};
use rustc::hir::def_id::{DefId, LOCAL_CRATE};
use rustc::session::Session;
use rustc::session::config::Sanitizer;
@@ -123,11 +123,37 @@ pub fn llvm_target_features(sess: &Session) -> impl Iterator<Item = &str> {
/// Composite function which sets LLVM attributes for function depending on its AST (#[attribute])
/// attributes.
-pub fn from_fn_attrs(cx: &CodegenCx, llfn: ValueRef, id: DefId) {
- let codegen_fn_attrs = cx.tcx.codegen_fn_attrs(id);
+pub fn from_fn_attrs(
+ cx: &CodegenCx,
+ llfn: ValueRef,
+ id: Option<DefId>,
+) {
+ let codegen_fn_attrs = id.map(|id| cx.tcx.codegen_fn_attrs(id))
+ .unwrap_or(CodegenFnAttrs::new());
inline(llfn, codegen_fn_attrs.inline);
+ // The `uwtable` attribute according to LLVM is:
+ //
+ // This attribute indicates that the ABI being targeted requires that an
+ // unwind table entry be produced for this function even if we can show
+ // that no exceptions passes by it. This is normally the case for the
+ // ELF x86-64 abi, but it can be disabled for some compilation units.
+ //
+ // Typically when we're compiling with `-C panic=abort` (which implies this
+ // `no_landing_pads` check) we don't need `uwtable` because we can't
+ // generate any exceptions! On Windows, however, exceptions include other
+ // events such as illegal instructions, segfaults, etc. This means that on
+ // Windows we end up still needing the `uwtable` attribute even if the `-C
+ // panic=abort` flag is passed.
+ //
+ // You can also find more info on why Windows is whitelisted here in:
+ // https://bugzilla.mozilla.org/show_bug.cgi?id=1302078
+ if !cx.sess().no_landing_pads() ||
+ cx.sess().target.target.options.requires_uwtable {
+ attributes::emit_uwtable(llfn, true);
+ }
+
set_frame_pointer_elimination(cx, llfn);
set_probestack(cx, llfn);
@@ -151,7 +177,7 @@ pub fn from_fn_attrs(cx: &CodegenCx, llfn: ValueRef, id: DefId) {
// *in Rust code* may unwind. Foreign items like `extern "C" {
// fn foo(); }` are assumed not to unwind **unless** they have
// a `#[unwind]` attribute.
- } else if !cx.tcx.is_foreign_item(id) {
+ } else if id.map(|id| !cx.tcx.is_foreign_item(id)).unwrap_or(false) {
Some(true)
} else {
None
@@ -188,14 +214,16 @@ pub fn from_fn_attrs(cx: &CodegenCx, llfn: ValueRef, id: DefId) {
// Note that currently the `wasm-import-module` doesn't do anything, but
// eventually LLVM 7 should read this and ferry the appropriate import
// module to the output file.
- if cx.tcx.sess.target.target.arch == "wasm32" {
- if let Some(module) = wasm_import_module(cx.tcx, id) {
- llvm::AddFunctionAttrStringValue(
- llfn,
- llvm::AttributePlace::Function,
- cstr("wasm-import-module\0"),
- &module,
- );
+ if let Some(id) = id {
+ if cx.tcx.sess.target.target.arch == "wasm32" {
+ if let Some(module) = wasm_import_module(cx.tcx, id) {
+ llvm::AddFunctionAttrStringValue(
+ llfn,
+ llvm::AttributePlace::Function,
+ cstr("wasm-import-module\0"),
+ &module,
+ );
+ }
}
}
}
diff --git a/src/librustc_codegen_llvm/base.rs b/src/librustc_codegen_llvm/base.rs
index 223c04f420f3..b0461582ddcb 100644
--- a/src/librustc_codegen_llvm/base.rs
+++ b/src/librustc_codegen_llvm/base.rs
@@ -486,27 +486,6 @@ pub fn codegen_instance<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>, instance: Instance<'
cx.stats.borrow_mut().n_closures += 1;
- // The `uwtable` attribute according to LLVM is:
- //
- // This attribute indicates that the ABI being targeted requires that an
- // unwind table entry be produced for this function even if we can show
- // that no exceptions passes by it. This is normally the case for the
- // ELF x86-64 abi, but it can be disabled for some compilation units.
- //
- // Typically when we're compiling with `-C panic=abort` (which implies this
- // `no_landing_pads` check) we don't need `uwtable` because we can't
- // generate any exceptions! On Windows, however, exceptions include other
- // events such as illegal instructions, segfaults, etc. This means that on
- // Windows we end up still needing the `uwtable` attribute even if the `-C
- // panic=abort` flag is passed.
- //
- // You can also find more info on why Windows is whitelisted here in:
- // https://bugzilla.mozilla.org/show_bug.cgi?id=1302078
- if !cx.sess().no_landing_pads() ||
- cx.sess().target.target.options.requires_uwtable {
- attributes::emit_uwtable(lldecl, true);
- }
-
let mir = cx.tcx.instance_mir(instance.def);
mir::codegen_mir(cx, lldecl, &mir, instance, sig);
}
diff --git a/src/librustc_codegen_llvm/callee.rs b/src/librustc_codegen_llvm/callee.rs
index 2c01bd42cc77..97f07792ede8 100644
--- a/src/librustc_codegen_llvm/callee.rs
+++ b/src/librustc_codegen_llvm/callee.rs
@@ -97,7 +97,7 @@ pub fn get_fn<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
if instance.def.is_inline(tcx) {
attributes::inline(llfn, attributes::InlineAttr::Hint);
}
- attributes::from_fn_attrs(cx, llfn, instance.def.def_id());
+ attributes::from_fn_attrs(cx, llfn, Some(instance.def.def_id()));
let instance_def_id = instance.def_id();
diff --git a/src/librustc_codegen_llvm/intrinsic.rs b/src/librustc_codegen_llvm/intrinsic.rs
index 9c5c0f730c16..f69fce15dc55 100644
--- a/src/librustc_codegen_llvm/intrinsic.rs
+++ b/src/librustc_codegen_llvm/intrinsic.rs
@@ -10,6 +10,7 @@
#![allow(non_upper_case_globals)]
+use attributes;
use intrinsics::{self, Intrinsic};
use llvm;
use llvm::{ValueRef};
@@ -936,6 +937,7 @@ fn gen_fn<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
Abi::Rust
)));
let llfn = declare::define_internal_fn(cx, name, rust_fn_ty);
+ attributes::from_fn_attrs(cx, llfn, None);
let bx = Builder::new_block(cx, llfn, "entry-block");
codegen(bx);
llfn
diff --git a/src/librustc_codegen_llvm/mono_item.rs b/src/librustc_codegen_llvm/mono_item.rs
index a528008e3b4b..32d8b24e3c15 100644
--- a/src/librustc_codegen_llvm/mono_item.rs
+++ b/src/librustc_codegen_llvm/mono_item.rs
@@ -183,7 +183,7 @@ fn predefine_fn<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
if instance.def.is_inline(cx.tcx) {
attributes::inline(lldecl, attributes::InlineAttr::Hint);
}
- attributes::from_fn_attrs(cx, lldecl, instance.def.def_id());
+ attributes::from_fn_attrs(cx, lldecl, Some(instance.def.def_id()));
cx.instances.borrow_mut().insert(instance, lldecl);
}
--
2.17.1