Split out define_rust_probestack!, specialize for apple

Author: tmandry

src/probestack.rs

@@ -47,6 +47,73 @@ extern "C" {
     pub fn __rust_probestack();
 }
 
+// A wrapper for our implementation of __rust_probestack, which allows us to
+// keep the assembly inline while controlling all CFI directives in the assembly
+// emitted for the function.
+//
+// This is the ELF version.
+#[cfg(all(
+    any(target_arch = "x86_64", target_arch = "x86"),
+    not(target_vendor = "apple")
+))]
+macro_rules! define_rust_probestack {
+    ($body: expr) => {
+        concat!(
+            "
+            // We are about to define a 'function within a function.' Because the
+            // compiler will have emitted a .cfi_startproc at the beginning of
+            // __rust_probestack_wrapper, we need .cfi_endproc before we can define
+            // the contents of __rust_probestack.
+            .cfi_endproc
+
+            .pushsection .text.__rust_probestack
+            .globl __rust_probestack
+            .type  __rust_probestack, @function
+        __rust_probestack:
+            .cfi_startproc
+
+            ",
+            $body,
+            "
+
+            .cfi_endproc
+
+            .size __rust_probestack, . - __rust_probestack
+            .popsection
+
+            // Similar to above, we add .cfi_startproc here to match the
+            // .cfi_endproc emitted at the end of __rust_probestack_wrapper.
+            .cfi_startproc
+            "
+        )
+    };
+}
+
+// Same as above, but for Mach-O.
+#[cfg(all(
+    any(target_arch = "x86_64", target_arch = "x86"),
+    target_vendor = "apple"
+))]
+macro_rules! define_rust_probestack {
+    ($body: expr) => {
+        concat!(
+            "
+            .cfi_endproc
+            .globl __rust_probestack
+        __rust_probestack:
+            .cfi_startproc
+
+            ",
+            $body,
+            "
+
+            .cfi_endproc
+            .cfi_startproc
+            "
+        )
+    };
+}
+
 #[naked]
 #[no_mangle]
 #[cfg(all(target_arch = "x86_64", not(feature = "mangled-names")))]
@@ -56,18 +123,7 @@ pub unsafe extern "C" fn __rust_probestack_wrapper() {
     //
     // The ABI here is that the stack frame size is located in `%rax`. Upon
     // return we're not supposed to modify `%rsp` or `%rax`.
-    asm!("
-        // We are about to define a 'function within a function.' Because the
-        // compiler will have emitted a .cfi_startproc at the beginning of
-        // __rust_probestack_wrapper, we need .cfi_endproc before we can define
-        // the contents of __rust_probestack.
-        .cfi_endproc
-
-        .pushsection .text.__rust_probestack
-        .globl __rust_probestack
-        .type  __rust_probestack, @function
-    __rust_probestack:
-        .cfi_startproc
+    asm!(define_rust_probestack!("
         pushq  %rbp
         .cfi_adjust_cfa_offset 8
         .cfi_offset %rbp, -16
@@ -114,15 +170,7 @@ pub unsafe extern "C" fn __rust_probestack_wrapper() {
         .cfi_def_cfa_register %rsp
         .cfi_adjust_cfa_offset -8
         ret
-        .cfi_endproc
-
-        .size __rust_probestack, . - __rust_probestack
-        .popsection
-
-        // Similar to above, we add .cfi_startproc here to match the
-        // .cfi_endproc emitted at the end of __rust_probestack_wrapper.
-        .cfi_startproc
-    " ::: "memory" : "volatile");
+    ") ::: "memory" : "volatile");
     ::core::intrinsics::unreachable();
 }
 
@@ -135,14 +183,7 @@ pub unsafe extern "C" fn __rust_probestack_wrapper() {
     // function basically can't tamper with anything.
     //
     // The ABI here is the same as x86_64, except everything is 32-bits large.
-    asm!("
-        .cfi_endproc
-
-        .pushsection .text.__rust_probestack
-        .globl __rust_probestack
-        .type  __rust_probestack, @function
-    __rust_probestack:
-        .cfi_startproc
+    asm!(define_rust_probestack!("
         push   %ebp
         .cfi_adjust_cfa_offset 4
         .cfi_offset %ebp, -8
@@ -170,12 +211,6 @@ pub unsafe extern "C" fn __rust_probestack_wrapper() {
         .cfi_def_cfa_register %esp
         .cfi_adjust_cfa_offset -4
         ret
-        .cfi_endproc
-
-        .size __rust_probestack, . - __rust_probestack
-        .popsection
-
-        .cfi_startproc
-    " ::: "memory" : "volatile");
+    ") ::: "memory" : "volatile");
     ::core::intrinsics::unreachable();
 }