Auto merge of #77885 - erikdesjardins:probeasm, r=cuviper

Use probe-stack=inline-asm in LLVM 11+

Fixes (?) #74405, related to #43241

r? `@cuviper`

4 files changed, 16 insertions, 9 deletions

diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index 97c38e04bc1..700f32e15b9 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -127,13 +127,18 @@ fn set_probestack(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
         return;
     }
 
-    // Flag our internal `__rust_probestack` function as the stack probe symbol.
-    // This is defined in the `compiler-builtins` crate for each architecture.
     llvm::AddFunctionAttrStringValue(
         llfn,
         llvm::AttributePlace::Function,
         const_cstr!("probe-stack"),
-        const_cstr!("__rust_probestack"),
+        if llvm_util::get_version() < (11, 0, 1) {
+            // Flag our internal `__rust_probestack` function as the stack probe symbol.
+            // This is defined in the `compiler-builtins` crate for each architecture.
+            const_cstr!("__rust_probestack")
+        } else {
+            // On LLVM 11+, emit inline asm for stack probes instead of a function call.
+            const_cstr!("inline-asm")
+        },
     );
 }
 
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index 8dd40308075..6acd26bd415 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -114,7 +114,7 @@ pub unsafe fn create_module(
     let llmod = llvm::LLVMModuleCreateWithNameInContext(mod_name.as_ptr(), llcx);
 
     let mut target_data_layout = sess.target.data_layout.clone();
-    if llvm_util::get_major_version() < 10
+    if llvm_util::get_version() < (10, 0, 0)
         && (sess.target.arch == "x86" || sess.target.arch == "x86_64")
     {
         target_data_layout = strip_x86_address_spaces(target_data_layout);
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index eb4f36266db..d9f42efebab 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -1811,6 +1811,7 @@ extern "C" {
     pub fn LLVMRustDebugMetadataVersion() -> u32;
     pub fn LLVMRustVersionMajor() -> u32;
     pub fn LLVMRustVersionMinor() -> u32;
+    pub fn LLVMRustVersionPatch() -> u32;
 
     pub fn LLVMRustAddModuleFlag(M: &Module, name: *const c_char, value: u32);
 
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index a9d57ea8b8a..6c2a871e520 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -171,16 +171,17 @@ pub fn target_features(sess: &Session) -> Vec<Symbol> {
 }
 
 pub fn print_version() {
+    let (major, minor, patch) = get_version();
+    println!("LLVM version: {}.{}.{}", major, minor, patch);
+}
+
+pub fn get_version() -> (u32, u32, u32) {
     // Can be called without initializing LLVM
     unsafe {
-        println!("LLVM version: {}.{}", llvm::LLVMRustVersionMajor(), llvm::LLVMRustVersionMinor());
+        (llvm::LLVMRustVersionMajor(), llvm::LLVMRustVersionMinor(), llvm::LLVMRustVersionPatch())
     }
 }
 
-pub fn get_major_version() -> u32 {
-    unsafe { llvm::LLVMRustVersionMajor() }
-}
-
 pub fn print_passes() {
     // Can be called without initializing LLVM
     unsafe {