Rollup merge of #59506 - JohnTitor:improve-mcount, r=nagisa

Use platform dependent mcount function

close #59097

This pull-request is based on #57244 and [here](https://github.com/llvm-mirror/clang/search?q=MCountName&unscoped_MCountName).

r? @nagisa

Author: Centril

src/librustc_codegen_llvm/attributes.rs

@@ -77,9 +77,15 @@ pub fn set_instrument_function(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
     if cx.sess().instrument_mcount() {
         // Similar to `clang -pg` behavior. Handled by the
         // `post-inline-ee-instrument` LLVM pass.
+
+        // The function name varies on platforms.
+        // See test/CodeGen/mcount.c in clang.
+        let mcount_name = CString::new(
+            cx.sess().target.target.options.target_mcount.as_str().as_bytes()).unwrap();
+
         llvm::AddFunctionAttrStringValue(
             llfn, llvm::AttributePlace::Function,
-            const_cstr!("instrument-function-entry-inlined"), const_cstr!("mcount"));
+            const_cstr!("instrument-function-entry-inlined"), &mcount_name);
     }
 }
 

src/librustc_target/spec/aarch64_unknown_linux_gnu.rs

@@ -17,6 +17,7 @@ pub fn target() -> TargetResult {
         linker_flavor: LinkerFlavor::Gcc,
         options: TargetOptions {
             abi_blacklist: super::arm_base::abi_blacklist(),
+            target_mcount: "\u{1}_mcount".to_string(),
             .. base
         },
     })

src/librustc_target/spec/aarch64_unknown_linux_musl.rs

@@ -17,6 +17,7 @@ pub fn target() -> TargetResult {
         linker_flavor: LinkerFlavor::Gcc,
         options: TargetOptions {
             abi_blacklist: super::arm_base::abi_blacklist(),
+            target_mcount: "\u{1}_mcount".to_string(),
             .. base
         },
     })

src/librustc_target/spec/aarch64_unknown_netbsd.rs

@@ -1,4 +1,4 @@
-use crate::spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::netbsd_base::opts();
@@ -16,6 +16,9 @@ pub fn target() -> TargetResult {
         target_env: String::new(),
         target_vendor: "unknown".to_string(),
         linker_flavor: LinkerFlavor::Gcc,
-        options: base,
+        options: TargetOptions {
+            target_mcount: "__mcount".to_string(),
+            .. base
+        },
     })
 }

src/librustc_target/spec/arm_unknown_linux_gnueabi.rs

@@ -18,6 +18,7 @@ pub fn target() -> TargetResult {
         options: TargetOptions {
             features: "+strict-align,+v6".to_string(),
             abi_blacklist: super::arm_base::abi_blacklist(),
+            target_mcount: "\u{1}__gnu_mcount_nc".to_string(),
             .. base
         },
     })

src/librustc_target/spec/arm_unknown_linux_gnueabihf.rs

@@ -18,6 +18,7 @@ pub fn target() -> TargetResult {
         options: TargetOptions {
             features: "+strict-align,+v6,+vfp2".to_string(),
             abi_blacklist: super::arm_base::abi_blacklist(),
+            target_mcount: "\u{1}__gnu_mcount_nc".to_string(),
             .. base
         }
     })

src/librustc_target/spec/arm_unknown_linux_musleabi.rs

@@ -23,6 +23,7 @@ pub fn target() -> TargetResult {
         linker_flavor: LinkerFlavor::Gcc,
         options: TargetOptions {
             abi_blacklist: super::arm_base::abi_blacklist(),
+            target_mcount: "\u{1}mcount".to_string(),
             .. base
         },
     })

src/librustc_target/spec/arm_unknown_linux_musleabihf.rs

@@ -23,6 +23,7 @@ pub fn target() -> TargetResult {
         linker_flavor: LinkerFlavor::Gcc,
         options: TargetOptions {
             abi_blacklist: super::arm_base::abi_blacklist(),
+            target_mcount: "\u{1}mcount".to_string(),
             .. base
         },
     })

src/librustc_target/spec/armv4t_unknown_linux_gnueabi.rs

@@ -19,6 +19,7 @@ pub fn target() -> TargetResult {
             // Atomic operations provided by compiler-builtins
             max_atomic_width: Some(32),
             abi_blacklist: super::arm_base::abi_blacklist(),
+            target_mcount: "\u{1}__gnu_mcount_nc".to_string(),
             .. base
         }
     })

src/librustc_target/spec/armv5te_unknown_linux_gnueabi.rs

@@ -19,6 +19,7 @@ pub fn target() -> TargetResult {
             // Atomic operations provided by compiler-builtins
             max_atomic_width: Some(32),
             abi_blacklist: super::arm_base::abi_blacklist(),
+            target_mcount: "\u{1}__gnu_mcount_nc".to_string(),
             .. base
         }
     })