rt: Give upcall_del_stack the same convention as other upcalls

Author: brson

src/rt/arch/i386/morestack.S

@@ -68,6 +68,7 @@
 
 #if defined(__APPLE__)
 #define RUST_GET_TASK           L_rust_get_task$stub
+#define UPCALL_DEL_STACK        L_upcall_del_stack$stub
 #define UPCALL_CALL_C           L_upcall_call_shim_on_c_stack$stub
 #define MORESTACK               ___morestack
 #else
@@ -87,8 +88,8 @@
 #endif
 
 .globl UPCALL_NEW_STACK
-.globl UPCALL_DEL_STACK
 #ifndef __APPLE__
+.globl UPCALL_DEL_STACK
 .globl RUST_GET_TASK
 .globl UPCALL_CALL_C_STACK
 #endif
@@ -213,24 +214,13 @@ MORESTACK:
 	// Switch back to the rust stack
 	movl %ebp, %esp
 
-	// Remember that __morestack is called misaligned so %ebp
-	// is not aligned to a 16-byte boundary, these 4 bytes realign.
-	subl $4, %esp
+	// Realign stack - remember that __morestack was called misaligned
+	subl $12, %esp
 
 	// Now that we're on the return path we want to avoid
 	// stomping on %eax. FIXME: Need to save and restore %eax to
 	// actually preserve it across the call to delete the stack
-#ifdef __APPLE__
-	call 1f
-1:	popl %ecx
-	movl L_upcall_del_stack$non_lazy_ptr-1b(%ecx),%ecx
-	pushl %ecx
-#else
-	pushl $UPCALL_DEL_STACK
-#endif
-
-	pushl $0
-	call UPCALL_CALL_C
+	call UPCALL_DEL_STACK
 
 	addl $12,%esp
 
@@ -267,9 +257,6 @@ MORESTACK:
 L_upcall_new_stack$non_lazy_ptr:
 	.indirect_symbol _upcall_new_stack
 	.long 0
-L_upcall_del_stack$non_lazy_ptr:
-	.indirect_symbol _upcall_del_stack
-	.long 0
 
 .section __IMPORT,__jump_table,symbol_stubs,pure_instructions+self_modifying_code,5
 
@@ -278,6 +265,10 @@ L_rust_get_task$stub:
 	.indirect_symbol _rust_get_task
 	.ascii	 "\364\364\364\364\364"
 
+L_upcall_del_stack$stub:
+	.indirect_symbol _upcall_del_stack
+	.ascii	 "\364\364\364\364\364"
+
 L_upcall_call_shim_on_c_stack$stub:
 	.indirect_symbol _upcall_call_shim_on_c_stack
 	.ascii	 "\364\364\364\364\364"

src/rt/arch/x86_64/morestack.S

@@ -117,13 +117,11 @@ MORESTACK:
 	pushq $0
 
 	// FIXME: Should preserve %rax here
-	movq UPCALL_DEL_STACK@GOTPCREL(%rip), %rsi
-	movq $0, %rdi
 #ifdef __APPLE__
-	call UPCALL_CALL_C
+	call UPCALL_DEL_STACK
 #endif
 #ifdef __linux__
-	call UPCALL_CALL_C@PLT
+	call UPCALL_DEL_STACK@PLT
 #endif
 
 	addq $8, %rsp

src/rt/rust_upcall.cpp

@@ -614,13 +614,17 @@ upcall_new_stack(struct rust_new_stack2_args *args) {
                                       args->args_sz);
 }
 
-// FIXME: As above
 extern "C" CDECL void
-upcall_del_stack() {
+upcall_s_del_stack() {
     rust_task *task = rust_scheduler::get_task();
     task->del_stack();
 }
 
+extern "C" CDECL void
+upcall_del_stack() {
+    UPCALL_SWITCH_STACK(NULL, upcall_s_del_stack);
+}
+
 // Landing pads need to call this to insert the
 // correct limit into TLS.
 // NB: This must run on the Rust stack because it