Auto merge of #113814 - ChoKyuWon:master, r=davidtwco

Replace the \01__gnu_mcount_nc to LLVM intrinsic for ARM

Current `-Zinstrument-mcount` for ARM32 use the `\01__gnu_mcount_nc` directly for its instrumentation function.

However, the LLVM does not use this mcount function directly, but it wraps it to intrinsic, `llvm.arm.gnu.eabi.mcount` and the transform pass also only handle the intrinsic.

As a result, current `-Zinstrument-mcount` not work on ARM32. Refer: https://github.com/namhyung/uftrace/issues/1764

This commit replaces the mcount name from native function to the LLVM intrinsic so that the transform pass can handle it.

8 files changed, 16 insertions, 1 deletions

diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index 4c9094bf1f5..b6c01545f30 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -128,7 +128,10 @@ fn instrument_function_attr<'ll>(cx: &CodegenCx<'ll, '_>) -> SmallVec<[&'ll Attr
 
         // The function name varies on platforms.
         // See test/CodeGen/mcount.c in clang.
-        let mcount_name = cx.sess().target.mcount.as_ref();
+        let mcount_name = match &cx.sess().target.llvm_mcount_intrinsic {
+            Some(llvm_mcount_intrinsic) => llvm_mcount_intrinsic.as_ref(),
+            None => cx.sess().target.mcount.as_ref(),
+        };
 
         attrs.push(llvm::CreateAttrStringValue(
             cx.llcx,
diff --git a/compiler/rustc_target/src/spec/arm_unknown_linux_gnueabi.rs b/compiler/rustc_target/src/spec/arm_unknown_linux_gnueabi.rs
index c0f1827ad3f..400030ca0c6 100644
--- a/compiler/rustc_target/src/spec/arm_unknown_linux_gnueabi.rs
+++ b/compiler/rustc_target/src/spec/arm_unknown_linux_gnueabi.rs
@@ -11,6 +11,7 @@ pub fn target() -> Target {
             features: "+strict-align,+v6".into(),
             max_atomic_width: Some(64),
             mcount: "\u{1}__gnu_mcount_nc".into(),
+            llvm_mcount_intrinsic: Some("llvm.arm.gnu.eabi.mcount".into()),
             ..super::linux_gnu_base::opts()
         },
     }
diff --git a/compiler/rustc_target/src/spec/arm_unknown_linux_gnueabihf.rs b/compiler/rustc_target/src/spec/arm_unknown_linux_gnueabihf.rs
index 79b8958c22a..6228fb15a83 100644
--- a/compiler/rustc_target/src/spec/arm_unknown_linux_gnueabihf.rs
+++ b/compiler/rustc_target/src/spec/arm_unknown_linux_gnueabihf.rs
@@ -11,6 +11,7 @@ pub fn target() -> Target {
             features: "+strict-align,+v6,+vfp2,-d32".into(),
             max_atomic_width: Some(64),
             mcount: "\u{1}__gnu_mcount_nc".into(),
+            llvm_mcount_intrinsic: Some("llvm.arm.gnu.eabi.mcount".into()),
             ..super::linux_gnu_base::opts()
         },
     }
diff --git a/compiler/rustc_target/src/spec/armeb_unknown_linux_gnueabi.rs b/compiler/rustc_target/src/spec/armeb_unknown_linux_gnueabi.rs
index 4836f3cf720..1d66515a72e 100644
--- a/compiler/rustc_target/src/spec/armeb_unknown_linux_gnueabi.rs
+++ b/compiler/rustc_target/src/spec/armeb_unknown_linux_gnueabi.rs
@@ -13,6 +13,7 @@ pub fn target() -> Target {
             endian: Endian::Big,
             max_atomic_width: Some(64),
             mcount: "\u{1}__gnu_mcount_nc".into(),
+            llvm_mcount_intrinsic: Some("llvm.arm.gnu.eabi.mcount".into()),
             ..super::linux_gnu_base::opts()
         },
     }
diff --git a/compiler/rustc_target/src/spec/armv4t_unknown_linux_gnueabi.rs b/compiler/rustc_target/src/spec/armv4t_unknown_linux_gnueabi.rs
index 1de63a920c8..cffebcc9581 100644
--- a/compiler/rustc_target/src/spec/armv4t_unknown_linux_gnueabi.rs
+++ b/compiler/rustc_target/src/spec/armv4t_unknown_linux_gnueabi.rs
@@ -12,6 +12,7 @@ pub fn target() -> Target {
             // Atomic operations provided by compiler-builtins
             max_atomic_width: Some(32),
             mcount: "\u{1}__gnu_mcount_nc".into(),
+            llvm_mcount_intrinsic: Some("llvm.arm.gnu.eabi.mcount".into()),
             has_thumb_interworking: true,
             ..super::linux_gnu_base::opts()
         },
diff --git a/compiler/rustc_target/src/spec/armv6_unknown_freebsd.rs b/compiler/rustc_target/src/spec/armv6_unknown_freebsd.rs
index b7cfccc8b3d..4a8aa31576f 100644
--- a/compiler/rustc_target/src/spec/armv6_unknown_freebsd.rs
+++ b/compiler/rustc_target/src/spec/armv6_unknown_freebsd.rs
@@ -13,6 +13,7 @@ pub fn target() -> Target {
             features: "+v6,+vfp2,-d32".into(),
             max_atomic_width: Some(64),
             mcount: "\u{1}__gnu_mcount_nc".into(),
+            llvm_mcount_intrinsic: Some("llvm.arm.gnu.eabi.mcount".into()),
             ..super::freebsd_base::opts()
         },
     }
diff --git a/compiler/rustc_target/src/spec/armv7_unknown_linux_gnueabi.rs b/compiler/rustc_target/src/spec/armv7_unknown_linux_gnueabi.rs
index 903042d7e7a..73ae212a7a6 100644
--- a/compiler/rustc_target/src/spec/armv7_unknown_linux_gnueabi.rs
+++ b/compiler/rustc_target/src/spec/armv7_unknown_linux_gnueabi.rs
@@ -14,6 +14,7 @@ pub fn target() -> Target {
             features: "+v7,+thumb2,+soft-float,-neon".into(),
             max_atomic_width: Some(64),
             mcount: "\u{1}__gnu_mcount_nc".into(),
+            llvm_mcount_intrinsic: Some("llvm.arm.gnu.eabi.mcount".into()),
             ..super::linux_gnu_base::opts()
         },
     }
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index af2b96ccb51..e18f35ac5ff 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -1922,6 +1922,9 @@ pub struct TargetOptions {
     /// Use platform dependent mcount function
     pub mcount: StaticCow<str>,
 
+    /// Use LLVM intrinsic for mcount function name
+    pub llvm_mcount_intrinsic: Option<StaticCow<str>>,
+
     /// LLVM ABI name, corresponds to the '-mabi' parameter available in multilib C compilers
     pub llvm_abiname: StaticCow<str>,
 
@@ -2183,6 +2186,7 @@ impl Default for TargetOptions {
             override_export_symbols: None,
             merge_functions: MergeFunctions::Aliases,
             mcount: "mcount".into(),
+            llvm_mcount_intrinsic: None,
             llvm_abiname: "".into(),
             relax_elf_relocations: false,
             llvm_args: cvs![],
@@ -2840,6 +2844,7 @@ impl Target {
         key!(override_export_symbols, opt_list);
         key!(merge_functions, MergeFunctions)?;
         key!(mcount = "target-mcount");
+        key!(llvm_mcount_intrinsic, optional);
         key!(llvm_abiname);
         key!(relax_elf_relocations, bool);
         key!(llvm_args, list);
@@ -3096,6 +3101,7 @@ impl ToJson for Target {
         target_option_val!(override_export_symbols);
         target_option_val!(merge_functions);
         target_option_val!(mcount, "target-mcount");
+        target_option_val!(llvm_mcount_intrinsic);
         target_option_val!(llvm_abiname);
         target_option_val!(relax_elf_relocations);
         target_option_val!(llvm_args);