From 4185b76dc3d3b22292033125487c07ce52276b11 Mon Sep 17 00:00:00 2001
From: Augie Fackler <augie@google.com>
Date: Wed, 15 Sep 2021 10:18:10 -0400
Subject: [PATCH] rustc_codegen_llvm: make sse4.2 imply crc32 for LLVM 14
This fixes compiling things like the `snap` crate after
https://reviews.llvm.org/D105462. I added a test that verifies the
additional attribute gets specified, and confirmed that I can build
cargo with both LLVM 13 and 14 with this change applied.
---
compiler/rustc_codegen_llvm/src/attributes.rs | 7 +-
compiler/rustc_codegen_llvm/src/llvm_util.rs | 82 +++++++++++--------
src/test/assembly/x86_64-sse_crc.rs | 12 +++
src/test/codegen/sse42-implies-crc32.rs | 16 ++++
4 files changed, 83 insertions(+), 34 deletions(-)
create mode 100644 src/test/assembly/x86_64-sse_crc.rs
create mode 100644 src/test/codegen/sse42-implies-crc32.rs
diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index 56b93f83466..51c70f0868f 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -305,9 +305,12 @@ pub fn from_fn_attrs(cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value, instance: ty::
let mut function_features = codegen_fn_attrs
.target_features
.iter()
- .map(|f| {
+ .flat_map(|f| {
let feature = &f.as_str();
- format!("+{}", llvm_util::to_llvm_feature(cx.tcx.sess, feature))
+ llvm_util::to_llvm_feature(cx.tcx.sess, feature)
+ .into_iter()
+ .map(|f| format!("+{}", f))
+ .collect::<Vec<String>>()
})
.chain(codegen_fn_attrs.instruction_set.iter().map(|x| match x {
InstructionSetAttr::ArmA32 => "-thumb-mode".to_string(),
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index 3b64ec1a991..f9172e43773 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -166,25 +166,32 @@ pub fn time_trace_profiler_finish(file_name: &str) {
// Though note that Rust can also be build with an external precompiled version of LLVM
// which might lead to failures if the oldest tested / supported LLVM version
// doesn't yet support the relevant intrinsics
-pub fn to_llvm_feature<'a>(sess: &Session, s: &'a str) -> &'a str {
+pub fn to_llvm_feature<'a>(sess: &Session, s: &'a str) -> Vec<&'a str> {
let arch = if sess.target.arch == "x86_64" { "x86" } else { &*sess.target.arch };
match (arch, s) {
- ("x86", "pclmulqdq") => "pclmul",
- ("x86", "rdrand") => "rdrnd",
- ("x86", "bmi1") => "bmi",
- ("x86", "cmpxchg16b") => "cx16",
- ("x86", "avx512vaes") => "vaes",
- ("x86", "avx512gfni") => "gfni",
- ("x86", "avx512vpclmulqdq") => "vpclmulqdq",
- ("aarch64", "fp") => "fp-armv8",
- ("aarch64", "fp16") => "fullfp16",
- ("aarch64", "fhm") => "fp16fml",
- ("aarch64", "rcpc2") => "rcpc-immo",
- ("aarch64", "dpb") => "ccpp",
- ("aarch64", "dpb2") => "ccdp",
- ("aarch64", "frintts") => "fptoint",
- ("aarch64", "fcma") => "complxnum",
- (_, s) => s,
+ ("x86", "sse4.2") => {
+ if get_version() >= (14, 0, 0) {
+ vec!["sse4.2", "crc32"]
+ } else {
+ vec!["sse4.2"]
+ }
+ }
+ ("x86", "pclmulqdq") => vec!["pclmul"],
+ ("x86", "rdrand") => vec!["rdrnd"],
+ ("x86", "bmi1") => vec!["bmi"],
+ ("x86", "cmpxchg16b") => vec!["cx16"],
+ ("x86", "avx512vaes") => vec!["vaes"],
+ ("x86", "avx512gfni") => vec!["gfni"],
+ ("x86", "avx512vpclmulqdq") => vec!["vpclmulqdq"],
+ ("aarch64", "fp") => vec!["fp-armv8"],
+ ("aarch64", "fp16") => vec!["fullfp16"],
+ ("aarch64", "fhm") => vec!["fp16fml"],
+ ("aarch64", "rcpc2") => vec!["rcpc-immo"],
+ ("aarch64", "dpb") => vec!["ccpp"],
+ ("aarch64", "dpb2") => vec!["ccdp"],
+ ("aarch64", "frintts") => vec!["fptoint"],
+ ("aarch64", "fcma") => vec!["complxnum"],
+ (_, s) => vec![s],
}
}
@@ -198,9 +205,13 @@ pub fn target_features(sess: &Session) -> Vec<Symbol> {
},
)
.filter(|feature| {
- let llvm_feature = to_llvm_feature(sess, feature);
- let cstr = CString::new(llvm_feature).unwrap();
- unsafe { llvm::LLVMRustHasFeature(target_machine, cstr.as_ptr()) }
+ for llvm_feature in to_llvm_feature(sess, feature) {
+ let cstr = CString::new(llvm_feature).unwrap();
+ if unsafe { llvm::LLVMRustHasFeature(target_machine, cstr.as_ptr()) } {
+ return true;
+ }
+ }
+ false
})
.map(|feature| Symbol::intern(feature))
.collect()
@@ -253,12 +264,19 @@ fn print_target_features(sess: &Session, tm: &llvm::TargetMachine) {
let mut rustc_target_features = supported_target_features(sess)
.iter()
.filter_map(|(feature, _gate)| {
- let llvm_feature = to_llvm_feature(sess, *feature);
- // LLVM asserts that these are sorted. LLVM and Rust both use byte comparison for these strings.
- target_features.binary_search_by_key(&llvm_feature, |(f, _d)| *f).ok().map(|index| {
- let (_f, desc) = target_features.remove(index);
- (*feature, desc)
- })
+ for llvm_feature in to_llvm_feature(sess, *feature) {
+ // LLVM asserts that these are sorted. LLVM and Rust both use byte comparison for these strings.
+ match target_features.binary_search_by_key(&llvm_feature, |(f, _d)| (*f)).ok().map(
+ |index| {
+ let (_f, desc) = target_features.remove(index);
+ (*feature, desc)
+ },
+ ) {
+ Some(v) => return Some(v),
+ None => {}
+ }
+ }
+ None
})
.collect::<Vec<_>>();
rustc_target_features.extend_from_slice(&[(
@@ -373,30 +391,30 @@ pub fn llvm_global_features(sess: &Session) -> Vec<String> {
let filter = |s: &str| {
if s.is_empty() {
- return None;
+ return vec![];
}
let feature = if s.starts_with('+') || s.starts_with('-') {
&s[1..]
} else {
- return Some(s.to_string());
+ return vec![s.to_string()];
};
// Rustc-specific feature requests like `+crt-static` or `-crt-static`
// are not passed down to LLVM.
if RUSTC_SPECIFIC_FEATURES.contains(&feature) {
- return None;
+ return vec![];
}
// ... otherwise though we run through `to_llvm_feature` feature when
// passing requests down to LLVM. This means that all in-language
// features also work on the command line instead of having two
// different names when the LLVM name and the Rust name differ.
- Some(format!("{}{}", &s[..1], to_llvm_feature(sess, feature)))
+ to_llvm_feature(sess, feature).iter().map(|f| format!("{}{}", &s[..1], f)).collect()
};
// Features implied by an implicit or explicit `--target`.
- features.extend(sess.target.features.split(',').filter_map(&filter));
+ features.extend(sess.target.features.split(',').flat_map(&filter));
// -Ctarget-features
- features.extend(sess.opts.cg.target_feature.split(',').filter_map(&filter));
+ features.extend(sess.opts.cg.target_feature.split(',').flat_map(&filter));
features
}
diff --git a/src/test/assembly/x86_64-sse_crc.rs b/src/test/assembly/x86_64-sse_crc.rs
new file mode 100644
index 00000000000..cdbf057b80b
--- /dev/null
+++ b/src/test/assembly/x86_64-sse_crc.rs
@@ -0,0 +1,12 @@
+// only-x86_64
+// assembly-output: emit-asm
+// compile-flags: --crate-type staticlib -Ctarget-feature=+sse4.2
+
+// CHECK-LABEL: banana
+// CHECK: crc32
+#[no_mangle]
+pub unsafe fn banana(v: u8) -> u32 {
+ use std::arch::x86_64::*;
+ let out = !0u32;
+ _mm_crc32_u8(out, v)
+}
diff --git a/src/test/codegen/sse42-implies-crc32.rs b/src/test/codegen/sse42-implies-crc32.rs
new file mode 100644
index 00000000000..47b1a899340
--- /dev/null
+++ b/src/test/codegen/sse42-implies-crc32.rs
@@ -0,0 +1,16 @@
+// only-x86_64
+// min-llvm-version: 14.0
+// compile-flags: -Copt-level=3
+
+#![crate_type = "lib"]
+
+#[cfg(target_arch = "x86_64")]
+#[target_feature(enable = "sse4.2")]
+#[no_mangle]
+pub unsafe fn crc32sse(v: u8) -> u32 {
+ use std::arch::x86_64::*;
+ let out = !0u32;
+ _mm_crc32_u8(out, v)
+}
+
+// CHECK: attributes #0 {{.*"target-features"="\+sse4.2,\+crc32"}}