[pypy-commit] pypy default: An attempt to find a general fix for arm/regalloc. In this backend (and not

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r96420:a243e4e0b21c
Date: 2019-04-05 13:49 +0200
http://bitbucket.org/pypy/pypy/changeset/a243e4e0b21c/

Log:	An attempt to find a general fix for arm/regalloc. In this backend
	(and not the others as far as I can tell), there can be a mixture of
	calls to make_sure_var_in_reg() and get_scratch_reg(). Try to make
	sure that none of these calls will accidentally return a register
	that a previous call already returned.

diff --git a/rpython/jit/backend/arm/regalloc.py b/rpython/jit/backend/arm/regalloc.py
--- a/rpython/jit/backend/arm/regalloc.py
+++ b/rpython/jit/backend/arm/regalloc.py
@@ -84,6 +84,8 @@
     return []
 
 class ARMRegisterManager(RegisterManager):
+    FORBID_TEMP_BOXES = True
+
     def return_constant(self, v, forbidden_vars=[], selected_reg=None):
         self._check_type(v)
         if isinstance(v, Const):
@@ -94,7 +96,7 @@
             else:
                 tp = INT
             loc = self.get_scratch_reg(tp,
-                    self.temp_boxes + forbidden_vars,
+                    forbidden_vars,
                     selected_reg=selected_reg)
             immvalue = self.convert_to_imm(v)
             self.assembler.load(loc, immvalue)
@@ -129,9 +131,9 @@
     def get_scratch_reg(self, type=FLOAT, forbidden_vars=[], selected_reg=None):
         assert type == FLOAT  # for now
         box = TempFloat()
-        self.temp_boxes.append(box)
         reg = self.force_allocate_reg(box, forbidden_vars=forbidden_vars,
                                                     selected_reg=selected_reg)
+        self.temp_boxes.append(box)
         return reg
 
 
@@ -164,9 +166,9 @@
             box = TempInt()
         else:
             box = TempPtr()
-        self.temp_boxes.append(box)
         reg = self.force_allocate_reg(box, forbidden_vars=forbidden_vars,
                                                     selected_reg=selected_reg)
+        self.temp_boxes.append(box)
         return reg
 
     def get_free_reg(self):
diff --git a/rpython/jit/backend/llsupport/regalloc.py b/rpython/jit/backend/llsupport/regalloc.py
--- a/rpython/jit/backend/llsupport/regalloc.py
+++ b/rpython/jit/backend/llsupport/regalloc.py
@@ -280,6 +280,7 @@
     no_lower_byte_regs    = []
     save_around_call_regs = []
     frame_reg             = None
+    FORBID_TEMP_BOXES     = False
 
     def __init__(self, longevity, frame_manager=None, assembler=None):
         self.free_regs = self.all_regs[:]
@@ -441,6 +442,8 @@
             reg = self.reg_bindings[next]
             if next in forbidden_vars:
                 continue
+            if self.FORBID_TEMP_BOXES and next in self.temp_boxes:
+                continue
             if selected_reg is not None:
                 if reg is selected_reg:
                     return next