Merge branch 'master' of github.com:graydon/rust

Author: nikomatsakis

src/comp/back/upcall.rs

@@ -27,7 +27,8 @@ type upcalls =
      dynastack_free: ValueRef,
      alloc_c_stack: ValueRef,
      call_shim_on_c_stack: ValueRef,
-     rust_personality: ValueRef};
+     rust_personality: ValueRef,
+     reset_stack_limit: ValueRef};
 
 fn declare_upcalls(targ_cfg: @session::config,
                    _tn: type_names,
@@ -89,7 +90,8 @@ fn declare_upcalls(targ_cfg: @session::config,
                                   // arguments: void *args, void *fn_ptr
                                   [T_ptr(T_i8()), T_ptr(T_i8())],
                                   int_t),
-          rust_personality: d("rust_personality", [], T_i32())
+          rust_personality: d("rust_personality", [], T_i32()),
+          reset_stack_limit: dv("reset_stack_limit", [])
          };
 }
 //

src/comp/middle/trans.rs

@@ -3904,6 +3904,11 @@ fn trans_landing_pad(bcx: @block_ctxt,
     // The landing pad block is a cleanup
     SetCleanup(bcx, llpad);
 
+    // Because we may have unwound across a stack boundary, we must call into
+    // the runtime to figure out which stack segment we are on and place the
+    // stack limit back into the TLS.
+    Call(bcx, bcx_ccx(bcx).upcalls.reset_stack_limit, []);
+
     // FIXME: This seems like a very naive and redundant way to generate the
     // landing pads, as we're re-generating all in-scope cleanups for each
     // function call. Probably good optimization opportunities here.

src/rt/arch/i386/record_sp.S

@@ -2,11 +2,14 @@
 
 #if defined(__APPLE__) || defined(_WIN32)
 #define RECORD_SP          _record_sp
+#define GET_SP             _get_sp
 #else
 #define RECORD_SP          record_sp
+#define GET_SP             get_sp
 #endif
 
 .globl RECORD_SP
+.globl GET_SP
 
 #if defined(__linux__)
 RECORD_SP:
@@ -25,3 +28,7 @@ RECORD_SP:
 	ret
 #endif
 #endif
+
+GET_SP:
+	movl %esp, %eax
+	ret

src/rt/arch/x86_64/morestack.S

@@ -132,6 +132,10 @@ MORESTACK:
 
 	addq $8, %rsp
 	popq %rbp
+#ifdef __linux__
+	.cfi_restore %rbp
+	.cfi_def_cfa %rsp, 8
+#endif
 	ret
 
 #if defined(__ELF__)

src/rt/arch/x86_64/record_sp.S

@@ -2,11 +2,14 @@
 
 #if defined(__APPLE__) || defined(_WIN32)
 #define RECORD_SP          _record_sp
+#define GET_SP             _get_sp
 #else
 #define RECORD_SP          record_sp
+#define GET_SP             get_sp
 #endif
 
 .globl RECORD_SP
+.globl GET_SP
 
 #if defined(__linux__)
 RECORD_SP:
@@ -23,3 +26,7 @@ RECORD_SP:
 	ret
 #endif
 #endif
+
+GET_SP:
+	movq %rsp, %rax
+	ret

src/rt/rust_task.cpp

@@ -18,11 +18,11 @@
 // to the rt, compiler and dynamic linker for running small functions
 // FIXME: We want this to be 128 but need to slim the red zone calls down
 #ifdef __i386__
-#define RED_ZONE_SIZE 2048
+#define RED_ZONE_SIZE 65536
 #endif
 
 #ifdef __x86_64__
-#define RED_ZONE_SIZE 2048
+#define RED_ZONE_SIZE 65536
 #endif
 
 // Stack size
@@ -613,6 +613,29 @@ rust_task::record_stack_limit() {
       "Stack size must be greater than LIMIT_OFFSET");
     record_sp(stk->data + LIMIT_OFFSET + RED_ZONE_SIZE);
 }
+
+extern "C" uintptr_t get_sp();
+
+/*
+Called by landing pads during unwinding to figure out which
+stack segment we are currently running on, delete the others,
+and record the stack limit (which was not restored when unwinding
+through __morestack).
+ */
+void
+rust_task::reset_stack_limit() {
+    uintptr_t sp = get_sp();
+    // Not positive these bounds for sp are correct.
+    // I think that the first possible value for esp on a new
+    // stack is stk->limit, which points one word in front of
+    // the first work to be pushed onto a new stack.
+    while (sp <= (uintptr_t)stk->data || stk->limit < sp) {
+        del_stk(this, stk);
+        A(sched, stk != NULL, "Failed to find the current stack");
+    }
+    record_stack_limit();
+}
+
 //
 // Local Variables:
 // mode: C++

src/rt/rust_task.h

@@ -200,6 +200,7 @@ rust_task : public kernel_owned<rust_task>, rust_cond
     void *new_stack(size_t stk_sz, void *args_addr, size_t args_sz);
     void del_stack();
     void record_stack_limit();
+    void reset_stack_limit();
 };
 
 //

src/rt/rust_upcall.cpp

@@ -259,6 +259,15 @@ upcall_del_stack() {
     task->del_stack();
 }
 
+// Landing pads need to call this to insert the
+// correct limit into TLS.
+// NB: This must be called on the Rust stack
+extern "C" CDECL void
+upcall_reset_stack_limit() {
+    rust_task *task = rust_scheduler::get_task();
+    task->reset_stack_limit();
+}
+
 extern "C" _Unwind_Reason_Code
 __gxx_personality_v0(int version,
                      _Unwind_Action actions,

src/rt/rustrt.def.in

@@ -69,6 +69,7 @@ upcall_vec_push
 upcall_call_shim_on_c_stack
 upcall_new_stack
 upcall_del_stack
+upcall_reset_stack_limit
 asm_call_on_stack
 rust_uv_default_loop
 rust_uv_loop_new

src/test/run-fail/morestack3.rs

@@ -25,10 +25,10 @@ resource and_then_get_big_again(_i: @int) {
             getbig(i - 1);
         }
     }
-    getbig(1000);
+    getbig(100);
 }
 
 fn main() {
     rustrt::set_min_stack(256u);
-    std::task::spawn(1000, getbig_and_fail);
+    std::task::spawn(100, getbig_and_fail);
 }