Author: David Schneider <[email protected]>
Branch: arm-backend-2
Changeset: r53894:e04c88a968bb
Date: 2012-03-22 13:35 +0000
http://bitbucket.org/pypy/pypy/changeset/e04c88a968bb/
Log: implement stack overflow checks in the backend
diff --git a/pypy/jit/backend/arm/assembler.py
b/pypy/jit/backend/arm/assembler.py
--- a/pypy/jit/backend/arm/assembler.py
+++ b/pypy/jit/backend/arm/assembler.py
@@ -61,6 +61,7 @@
self._regalloc = None
self.datablockwrapper = None
self.propagate_exception_path = 0
+ self.stack_check_slowpath = 0
self._compute_stack_size()
self._debug = False
self.loop_run_counters = []
@@ -108,6 +109,7 @@
self._build_propagate_exception_path()
if gc_ll_descr.get_malloc_slowpath_addr is not None:
self._build_malloc_slowpath()
+ self._build_stack_check_slowpath()
if gc_ll_descr.gcrootmap and gc_ll_descr.gcrootmap.is_shadow_stack:
self._build_release_gil(gc_ll_descr.gcrootmap)
self.memcpy_addr = self.cpu.cast_ptr_to_int(memcpy_fn)
@@ -238,6 +240,51 @@
self.gen_func_epilog(mc=mc)
self.propagate_exception_path = mc.materialize(self.cpu.asmmemmgr, [])
+ def _build_stack_check_slowpath(self):
+ _, _, slowpathaddr = self.cpu.insert_stack_check()
+ if slowpathaddr == 0 or self.cpu.propagate_exception_v < 0:
+ return # no stack check (for tests, or non-translated)
+ #
+ # make a "function" that is called immediately at the start of
+ # an assembler function. In particular, the stack looks like:
+ #
+ # | retaddr of caller | <-- aligned to a multiple of 16
+ # | saved argument regs |
+ # | my own retaddr | <-- sp
+ # +-----------------------+
+ #
+ mc = ARMv7Builder()
+ # save argument registers and return address
+ mc.PUSH([reg.value for reg in r.argument_regs] + [r.lr.value])
+ # stack is aligned here
+ # Pass current stack pointer as argument to the call
+ mc.MOV_rr(r.r0.value, r.sp.value)
+ #
+ mc.BL(slowpathaddr)
+
+ # check for an exception
+ mc.gen_load_int(r.r0.value, self.cpu.pos_exception())
+ mc.LDR_ri(r.r0.value, r.r0.value)
+ mc.TST_rr(r.r0.value, r.r0.value)
+ # restore registers and return
+ # We check for c.EQ here, meaning all bits zero in this case
+ mc.POP([reg.value for reg in r.argument_regs] + [r.pc.value],
cond=c.EQ)
+ # call on_leave_jitted_save_exc()
+ addr = self.cpu.get_on_leave_jitted_int(save_exception=True)
+ mc.BL(addr)
+ #
+ mc.gen_load_int(r.r0.value, self.cpu.propagate_exception_v)
+ #
+ # footer -- note the ADD, which skips the return address of this
+ # function, and will instead return to the caller's caller. Note
+ # also that we completely ignore the saved arguments, because we
+ # are interrupting the function.
+ mc.ADD_ri(r.sp.value, r.sp.value, (len(r.argument_regs) + 1) * WORD)
+ mc.POP([r.pc.value])
+ #
+ rawstart = mc.materialize(self.cpu.asmmemmgr, [])
+ self.stack_check_slowpath = rawstart
+
def setup_failure_recovery(self):
@rgc.no_collect
@@ -568,6 +615,27 @@
self.align()
self.gen_func_prolog()
+ def _call_header_with_stack_check(self):
+ if self.stack_check_slowpath == 0:
+ pass # no stack check (e.g. not translated)
+ else:
+ endaddr, lengthaddr, _ = self.cpu.insert_stack_check()
+ self.mc.PUSH([r.lr.value])
+ # load stack end
+ self.mc.gen_load_int(r.ip.value, endaddr) # load ip, [end]
+ self.mc.LDR_ri(r.ip.value, r.ip.value) # LDR ip, ip
+ # load stack length
+ self.mc.gen_load_int(r.lr.value, lengthaddr) # load lr, lengh
+ self.mc.LDR_ri(r.lr.value, r.lr.value) # ldr lr, *lengh
+ # calculate ofs
+ self.mc.SUB_rr(r.ip.value, r.ip.value, r.sp.value) # SUB ip,
current
+ # if ofs
+ self.mc.CMP_rr(r.ip.value, r.lr.value) # CMP ip, lr
+ self.mc.BL(self.stack_check_slowpath, c=c.HI) # call if ip >
lr
+ #
+ self.mc.POP([r.lr.value])
+ self._call_header()
+
# cpu interface
def assemble_loop(self, loopname, inputargs, operations, looptoken, log):
clt = CompiledLoopToken(self.cpu, looptoken.number)
@@ -584,7 +652,7 @@
operations = self._inject_debugging_code(looptoken, operations,
'e', looptoken.number)
- self._call_header()
+ self._call_header_with_stack_check()
sp_patch_location = self._prepare_sp_patch_position()
regalloc = Regalloc(assembler=self, frame_manager=ARMFrameManager())
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