Merge pull request #207 from sunfishcode/master

Add "volatile" and "memory" clobber to asm! that doesn't fall through.

Author: alexcrichton

src/arm.rs

@@ -11,7 +11,7 @@ pub unsafe fn __aeabi_uidivmod() {
           bl __udivmodsi4
           ldr r1, [sp]
           add sp, sp, #4
-          pop {pc}");
+          pop {pc}" ::: "memory" : "volatile");
     intrinsics::unreachable();
 }
 
@@ -26,7 +26,7 @@ pub unsafe fn __aeabi_uldivmod() {
           ldr r2, [sp, #8]
           ldr r3, [sp, #12]
           add sp, sp, #16
-          pop {r4, pc}");
+          pop {r4, pc}" ::: "memory" : "volatile");
     intrinsics::unreachable();
 }
 
@@ -38,7 +38,7 @@ pub unsafe fn __aeabi_idivmod() {
           pop {r1, r2}
           muls r2, r2, r0
           subs r1, r1, r2
-          pop {r4, pc}");
+          pop {r4, pc}" ::: "memory" : "volatile");
     intrinsics::unreachable();
 }
 
@@ -53,7 +53,7 @@ pub unsafe fn __aeabi_ldivmod() {
           ldr r2, [sp, #8]
           ldr r3, [sp, #12]
           add sp, sp, #16
-          pop {r4, pc}");
+          pop {r4, pc}" ::: "memory" : "volatile");
     intrinsics::unreachable();
 }
 

src/probestack.rs

@@ -82,7 +82,7 @@ pub unsafe extern fn __rust_probestack() {
         add    %rax,%rsp
 
         ret
-    ");
+    " ::: "memory" : "volatile");
     ::core::intrinsics::unreachable();
 }
 
@@ -111,6 +111,6 @@ pub unsafe extern fn __rust_probestack() {
         add    %eax,%esp
         pop    %ecx
         ret
-    ");
+    " ::: "memory" : "volatile");
     ::core::intrinsics::unreachable();
 }

src/x86.rs

@@ -29,7 +29,7 @@ pub unsafe fn ___chkstk_ms() {
         test   %ecx,(%ecx)
         pop    %eax
         pop    %ecx
-        ret");
+        ret" ::: "memory" : "volatile");
     intrinsics::unreachable();
 }
 
@@ -38,7 +38,8 @@ pub unsafe fn ___chkstk_ms() {
 #[naked]
 #[no_mangle]
 pub unsafe fn __alloca() {
-    asm!("jmp ___chkstk   // Jump to ___chkstk since fallthrough may be unreliable");
+    asm!("jmp ___chkstk   // Jump to ___chkstk since fallthrough may be unreliable"
+         ::: "memory" : "volatile");
     intrinsics::unreachable();
 }
 
@@ -66,6 +67,6 @@ pub unsafe fn ___chkstk() {
         mov    -4(%eax),%ecx    // restore ecx
         push   (%eax)           // push return address onto the stack
         sub    %esp,%eax        // restore the original value in eax
-        ret");
+        ret" ::: "memory" : "volatile");
     intrinsics::unreachable();
 }

src/x86_64.rs

@@ -29,7 +29,7 @@ pub unsafe fn ___chkstk_ms() {
         test   %rcx,(%rcx)
         pop    %rax
         pop    %rcx
-        ret");
+        ret" ::: "memory" : "volatile");
     intrinsics::unreachable();
 }
 
@@ -38,15 +38,17 @@ pub unsafe fn ___chkstk_ms() {
 #[no_mangle]
 pub unsafe fn __alloca() {
     asm!("mov    %rcx,%rax  // x64 _alloca is a normal function with parameter in rcx
-          jmp    ___chkstk  // Jump to ___chkstk since fallthrough may be unreliable");
+          jmp    ___chkstk  // Jump to ___chkstk since fallthrough may be unreliable"
+         ::: "memory" : "volatile");
     intrinsics::unreachable();
 }
 
 #[cfg(all(windows, target_env = "gnu", not(feature = "mangled-names")))]
 #[naked]
 #[no_mangle]
 pub unsafe fn ___chkstk() {
-    asm!("
+    asm!(
+        "
         push   %rcx
         cmp    $$0x1000,%rax
         lea    16(%rsp),%rcx  // rsp before calling this routine -> rcx
@@ -66,6 +68,8 @@ pub unsafe fn ___chkstk() {
         mov    -8(%rax),%rcx  // restore rcx
         push   (%rax)         // push return address onto the stack
         sub    %rsp,%rax      // restore the original value in rax
-        ret");
+        ret"
+        ::: "memory" : "volatile"
+    );
     intrinsics::unreachable();
 }