From 851fcc7a54262748b1aa9e16de91453998d896f3 Mon Sep 17 00:00:00 2001
From: Erik Desjardins <erikdesjardins@users.noreply.github.com>
Date: Sat, 26 Feb 2022 12:52:07 -0500
Subject: [PATCH 1/2] Revert "Auto merge of #92419 - erikdesjardins:coldland,
r=nagisa"
This reverts commit 4f49627c6fe2a32d1fed6310466bb0e1c535c0c0, reversing
changes made to 028c6f1454787c068ff5117e9000a1de4fd98374.
---
compiler/rustc_codegen_gcc/src/builder.rs | 2 +-
compiler/rustc_codegen_llvm/src/builder.rs | 17 ++-------
compiler/rustc_codegen_llvm/src/llvm/ffi.rs | 2 -
compiler/rustc_codegen_llvm/src/llvm_util.rs | 6 ---
compiler/rustc_codegen_ssa/src/mir/block.rs | 10 +++--
.../rustc_codegen_ssa/src/traits/builder.rs | 2 +-
.../rustc_llvm/llvm-wrapper/RustWrapper.cpp | 8 ----
src/test/codegen/unwind-landingpad-cold.rs | 15 --------
src/test/codegen/unwind-landingpad-inline.rs | 37 -------------------
9 files changed, 12 insertions(+), 87 deletions(-)
delete mode 100644 src/test/codegen/unwind-landingpad-cold.rs
delete mode 100644 src/test/codegen/unwind-landingpad-inline.rs
diff --git a/compiler/rustc_codegen_gcc/src/builder.rs b/compiler/rustc_codegen_gcc/src/builder.rs
index b430dc329cb..974e59b65ec 100644
--- a/compiler/rustc_codegen_gcc/src/builder.rs
+++ b/compiler/rustc_codegen_gcc/src/builder.rs
@@ -1403,7 +1403,7 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
self.cx
}
- fn apply_attrs_to_cleanup_callsite(&mut self, _llret: RValue<'gcc>) {
+ fn do_not_inline(&mut self, _llret: RValue<'gcc>) {
unimplemented!();
}
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index 5e78d6fc851..3703e902bb7 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -23,7 +23,6 @@ use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_span::Span;
use rustc_target::abi::{self, call::FnAbi, Align, Size, WrappingRange};
use rustc_target::spec::{HasTargetSpec, Target};
-use smallvec::SmallVec;
use std::borrow::Cow;
use std::ffi::CStr;
use std::iter;
@@ -1175,19 +1174,9 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
unsafe { llvm::LLVMBuildZExt(self.llbuilder, val, dest_ty, UNNAMED) }
}
- fn apply_attrs_to_cleanup_callsite(&mut self, llret: &'ll Value) {
- let mut attrs = SmallVec::<[_; 2]>::new();
-
- // Cleanup is always the cold path.
- attrs.push(llvm::AttributeKind::Cold.create_attr(self.llcx));
-
- // In LLVM versions with deferred inlining (currently, system LLVM < 14),
- // inlining drop glue can lead to exponential size blowup, see #41696 and #92110.
- if !llvm_util::is_rust_llvm() && llvm_util::get_version() < (14, 0, 0) {
- attrs.push(llvm::AttributeKind::NoInline.create_attr(self.llcx));
- }
-
- attributes::apply_to_callsite(llret, llvm::AttributePlace::Function, &attrs);
+ fn do_not_inline(&mut self, llret: &'ll Value) {
+ let noinline = llvm::AttributeKind::NoInline.create_attr(self.llcx);
+ attributes::apply_to_callsite(llret, llvm::AttributePlace::Function, &[noinline]);
}
}
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 31d1460e178..93eddb7359f 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -1932,8 +1932,6 @@ extern "C" {
pub fn LLVMRustVersionMinor() -> u32;
pub fn LLVMRustVersionPatch() -> u32;
- pub fn LLVMRustIsRustLLVM() -> bool;
-
/// Add LLVM module flags.
///
/// In order for Rust-C LTO to work, module flags must be compatible with Clang. What
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index b1c14c7e44b..6c974eb9c0b 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -257,12 +257,6 @@ pub fn get_version() -> (u32, u32, u32) {
}
}
-/// Returns `true` if this LLVM is Rust's bundled LLVM (and not system LLVM).
-pub fn is_rust_llvm() -> bool {
- // Can be called without initializing LLVM
- unsafe { llvm::LLVMRustIsRustLLVM() }
-}
-
pub fn print_passes() {
// Can be called without initializing LLVM
unsafe {
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index f6c41af41b4..a87daa8d6b8 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -166,7 +166,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
bx.invoke(fn_ty, fn_ptr, &llargs, ret_llbb, unwind_block, self.funclet(fx));
bx.apply_attrs_callsite(&fn_abi, invokeret);
if fx.mir[self.bb].is_cleanup {
- bx.apply_attrs_to_cleanup_callsite(invokeret);
+ bx.do_not_inline(invokeret);
}
if let Some((ret_dest, target)) = destination {
@@ -178,7 +178,11 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
let llret = bx.call(fn_ty, fn_ptr, &llargs, self.funclet(fx));
bx.apply_attrs_callsite(&fn_abi, llret);
if fx.mir[self.bb].is_cleanup {
- bx.apply_attrs_to_cleanup_callsite(llret);
+ // Cleanup is always the cold path. Don't inline
+ // drop glue. Also, when there is a deeply-nested
+ // struct, there are "symmetry" issues that cause
+ // exponential inlining - see issue #41696.
+ bx.do_not_inline(llret);
}
if let Some((ret_dest, target)) = destination {
@@ -1444,7 +1448,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let llret = bx.call(fn_ty, fn_ptr, &[], None);
bx.apply_attrs_callsite(&fn_abi, llret);
- bx.apply_attrs_to_cleanup_callsite(llret);
+ bx.do_not_inline(llret);
bx.unreachable();
diff --git a/compiler/rustc_codegen_ssa/src/traits/builder.rs b/compiler/rustc_codegen_ssa/src/traits/builder.rs
index 1c7fe060ea4..37f2bfd3c4f 100644
--- a/compiler/rustc_codegen_ssa/src/traits/builder.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/builder.rs
@@ -479,5 +479,5 @@ pub trait BuilderMethods<'a, 'tcx>:
) -> Self::Value;
fn zext(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value;
- fn apply_attrs_to_cleanup_callsite(&mut self, llret: Self::Value);
+ fn do_not_inline(&mut self, llret: Self::Value);
}
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index d627af48ba5..be3c1b02a05 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -694,14 +694,6 @@ extern "C" uint32_t LLVMRustVersionMinor() { return LLVM_VERSION_MINOR; }
extern "C" uint32_t LLVMRustVersionMajor() { return LLVM_VERSION_MAJOR; }
-extern "C" bool LLVMRustIsRustLLVM() {
-#ifdef LLVM_RUSTLLVM
- return true;
-#else
- return false;
-#endif
-}
-
extern "C" void LLVMRustAddModuleFlag(
LLVMModuleRef M,
Module::ModFlagBehavior MergeBehavior,
diff --git a/src/test/codegen/unwind-landingpad-cold.rs b/src/test/codegen/unwind-landingpad-cold.rs
deleted file mode 100644
index aa00b793654..00000000000
--- a/src/test/codegen/unwind-landingpad-cold.rs
+++ /dev/null
@@ -1,15 +0,0 @@
-// no-system-llvm: needs #92110
-// compile-flags: -Cno-prepopulate-passes
-#![crate_type = "lib"]
-
-// This test checks that drop calls in unwind landing pads
-// get the `cold` attribute.
-
-// CHECK-LABEL: @check_cold
-// CHECK: {{(call|invoke) void .+}}drop_in_place{{.+}} [[ATTRIBUTES:#[0-9]+]]
-// CHECK: attributes [[ATTRIBUTES]] = { cold }
-#[no_mangle]
-pub fn check_cold(f: fn(), x: Box<u32>) {
- // this may unwind
- f();
-}
diff --git a/src/test/codegen/unwind-landingpad-inline.rs b/src/test/codegen/unwind-landingpad-inline.rs
deleted file mode 100644
index ce78d075dd0..00000000000
--- a/src/test/codegen/unwind-landingpad-inline.rs
+++ /dev/null
@@ -1,37 +0,0 @@
-// no-system-llvm: needs #92110 + patch for Rust alloc/dealloc functions
-// compile-flags: -Copt-level=3
-#![crate_type = "lib"]
-
-// This test checks that we can inline drop_in_place in
-// unwind landing pads.
-
-// Without inlining, the box pointers escape via the call to drop_in_place,
-// and LLVM will not optimize out the pointer comparison.
-// With inlining, everything should be optimized out.
-// See https://github.com/rust-lang/rust/issues/46515
-// CHECK-LABEL: @check_no_escape_in_landingpad
-// CHECK: start:
-// CHECK-NEXT: ret void
-#[no_mangle]
-pub fn check_no_escape_in_landingpad(f: fn()) {
- let x = &*Box::new(0);
- let y = &*Box::new(0);
-
- if x as *const _ == y as *const _ {
- f();
- }
-}
-
-// Without inlining, the compiler can't tell that
-// dropping an empty string (in a landing pad) does nothing.
-// With inlining, the landing pad should be optimized out.
-// See https://github.com/rust-lang/rust/issues/87055
-// CHECK-LABEL: @check_eliminate_noop_drop
-// CHECK: start:
-// CHECK-NEXT: call void %g()
-// CHECK-NEXT: ret void
-#[no_mangle]
-pub fn check_eliminate_noop_drop(g: fn()) {
- let _var = String::new();
- g();
-}
From 0c784337494223441d53129688bd777ae8df7992 Mon Sep 17 00:00:00 2001
From: Erik Desjardins <erikdesjardins@users.noreply.github.com>
Date: Sun, 27 Feb 2022 23:15:49 -0500
Subject: [PATCH 2/2] update vec-shrink-panik test to allow panic_no_unwind in
landingpads
---
src/test/codegen/vec-shrink-panik.rs | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/src/test/codegen/vec-shrink-panik.rs b/src/test/codegen/vec-shrink-panik.rs
index 6b0ac78857a..18409014bde 100644
--- a/src/test/codegen/vec-shrink-panik.rs
+++ b/src/test/codegen/vec-shrink-panik.rs
@@ -16,6 +16,14 @@ pub fn shrink_to_fit(vec: &mut Vec<u32>) {
// CHECK-LABEL: @issue71861
#[no_mangle]
pub fn issue71861(vec: Vec<u32>) -> Box<[u32]> {
+ // CHECK-NOT: panic
+
+ // Call to panic_no_unwind in case of double-panic is expected,
+ // but other panics are not.
+ // CHECK: cleanup
+ // CHECK-NEXT: ; call core::panicking::panic_no_unwind
+ // CHECK-NEXT: panic_no_unwind
+
// CHECK-NOT: panic
vec.into_boxed_slice()
}
@@ -23,6 +31,17 @@ pub fn issue71861(vec: Vec<u32>) -> Box<[u32]> {
// CHECK-LABEL: @issue75636
#[no_mangle]
pub fn issue75636<'a>(iter: &[&'a str]) -> Box<[&'a str]> {
+ // CHECK-NOT: panic
+
+ // Call to panic_no_unwind in case of double-panic is expected,
+ // but other panics are not.
+ // CHECK: cleanup
+ // CHECK-NEXT: ; call core::panicking::panic_no_unwind
+ // CHECK-NEXT: panic_no_unwind
+
// CHECK-NOT: panic
iter.iter().copied().collect()
}
+
+// CHECK: ; core::panicking::panic_no_unwind
+// CHECK: declare void @{{.*}}panic_no_unwind