From 292663b8ef3f688e90bd5a8bd49f46288639b158 Mon Sep 17 00:00:00 2001
From: Brian Anderson <banderson@mozilla.com>
Date: Fri, 2 Dec 2011 17:44:23 -0800
Subject: [PATCH] rt: Implement 32-bit __morestack for mac

---
 src/rt/arch/i386/morestack.S | 74 ++++++++++++++++++++++++++----------
 src/rt/arch/i386/record_sp.S | 10 ++++-
 2 files changed, 63 insertions(+), 21 deletions(-)

diff --git a/src/rt/arch/i386/morestack.S b/src/rt/arch/i386/morestack.S
index 4eb5f0c2d2ae..519a5ca77119 100644
--- a/src/rt/arch/i386/morestack.S
+++ b/src/rt/arch/i386/morestack.S
@@ -5,18 +5,24 @@
 // LLVM generates a call to this to allocate more stack space in a function
 // prolog when we run out.
 
-#if defined(__APPLE__) || defined(_WIN32)
-#define UPCALL_NEW_STACK        _upcall_new_stack
-#define UPCALL_DEL_STACK        _upcall_del_stack
-#define RUST_GET_TASK           _rust_get_task
-#define UPCALL_CALL_C           _upcall_call_shim_on_c_stack
+#if defined(__APPLE__)
+#define RUST_GET_TASK           L_rust_get_task$stub
+#define UPCALL_CALL_C           L_upcall_call_shim_on_c_stack$stub
 #define MORESTACK               ___morestack
 #else
+#if defined(__linux__)
 #define UPCALL_NEW_STACK        upcall_new_stack
 #define UPCALL_DEL_STACK        upcall_del_stack
 #define RUST_GET_TASK           rust_get_task
 #define UPCALL_CALL_C           upcall_call_shim_on_c_stack
 #define MORESTACK               __morestack
+#else
+#define UPCALL_NEW_STACK        _upcall_new_stack
+#define UPCALL_DEL_STACK        _upcall_del_stack
+#define RUST_GET_TASK           _rust_get_task
+#define UPCALL_CALL_C           _upcall_call_shim_on_c_stack
+#define MORESTACK               __morestack
+#endif
 #endif
 
 // FIXME: Future LLVM patches remove these 8 alignment bytes from
@@ -43,7 +49,7 @@
 	.type MORESTACK,@function
 #endif
 
-#if defined(__linux__)
+#if defined(__linux__) || defined(__APPLE__)
 MORESTACK:
 
 	pushl %ebp
@@ -51,25 +57,33 @@ MORESTACK:
 	
 	// FIXME (1226): main is compiled with the split-stack prologue,
 	// causing it to call __morestack, so we have to jump back out
-	subl $24,%esp
+	subl $20,%esp
 	calll RUST_GET_TASK
 	testl %eax,%eax
 	jz .L$bail
 
 	// The arguments to rust_new_stack2
-	movl 36(%esp),%eax  // Size of stack arguments
+	movl 32(%esp),%eax  // Size of stack arguments
 	movl %eax,16(%esp)
-	leal 44+ALIGNMENT(%esp),%eax // Address of stack arguments
+	leal 40+ALIGNMENT(%esp),%eax // Address of stack arguments
 	movl %eax,12(%esp)
-	movl 32(%esp),%eax // The amount of stack needed
+	movl 28(%esp),%eax // The amount of stack needed
 	movl %eax,8(%esp)
 
+#ifdef __APPLE__
+	call 1f
+1:	popl %ebx
+	movl L_upcall_new_stack$non_lazy_ptr-1b(%ebx),%ecx
+	movl %ecx, 4(%esp)
+#else
 	movl $UPCALL_NEW_STACK,4(%esp)
+#endif
+
 	leal 8(%esp), %eax
 	movl %eax,(%esp)
 	call UPCALL_CALL_C
 
-	movl 28(%esp),%edx          // Grab the return pointer.
+	movl 24(%esp),%edx          // Grab the return pointer.
 	addl $RETURN_OFFSET,%edx    // Skip past the `add esp,4` and the `ret`.
 
 	movl %eax,%esp          // Switch stacks.
@@ -81,7 +95,15 @@ MORESTACK:
 	// Switch back to the rust stack
 	movl %ebp, %esp
 
+#ifdef __APPLE__
+	call 1f
+1:	popl %ebx
+	movl L_upcall_del_stack$non_lazy_ptr-1b(%ebx),%ecx
+	pushl %ecx
+#else
 	pushl $UPCALL_DEL_STACK
+#endif
+
 	pushl $0
 	call UPCALL_CALL_C
 
@@ -90,10 +112,10 @@ MORESTACK:
 	retl $8
 
 .L$bail:
-	movl 28(%esp),%edx
+	movl 24(%esp),%edx
 	addl $RETURN_OFFSET,%edx
 	
-	addl $24, %esp
+	addl $20, %esp
 	popl %ebp
 	addl $4+8+ALIGNMENT,%esp
 	
@@ -107,13 +129,25 @@ MORESTACK:
 
 #ifdef __APPLE__
 
-		.section	__IMPORT,__pointers,non_lazy_symbol_pointers
-rust_new_stack_sym:
-    .indirect_symbol RUST_NEW_STACK
-    .long 0
-rust_del_stack_sym:
-    .indirect_symbol RUST_DEL_STACK
-    .long 0
+	.section __IMPORT,__pointers,non_lazy_symbol_pointers
+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
+
+	// Linker will replace the hlts (the ascii) with jmp
+L_rust_get_task$stub:
+	.indirect_symbol _rust_get_task
+	.ascii	 "\364\364\364\364\364"
+
+L_upcall_call_shim_on_c_stack$stub:
+	.indirect_symbol _upcall_call_shim_on_c_stack
+	.ascii	 "\364\364\364\364\364"
+
+	.subsections_via_symbols
 #endif
 
diff --git a/src/rt/arch/i386/record_sp.S b/src/rt/arch/i386/record_sp.S
index 78c77b9859d2..153225e8187b 100644
--- a/src/rt/arch/i386/record_sp.S
+++ b/src/rt/arch/i386/record_sp.S
@@ -14,6 +14,14 @@ RECORD_SP:
 	movl %eax, %gs:48
 	ret
 #else
+#if defined(__APPLE__)
+RECORD_SP:
+	movl $0x48+90*4, %eax
+	movl 4(%esp), %ecx
+	movl %ecx, %gs:(%eax)
+	ret
+#else
 RECORD_SP:
 	ret
-#endif
\ No newline at end of file
+#endif
+#endif