Improved debugging.

Author: vidarh

regalloc.rb

@@ -163,7 +163,7 @@ def evict_by_cache cache
     return if !cache
     @cached.delete(cache.var)
     r = cache.reg
-    debug_is_register?(r)
+    debug_is_register?(r, "evict_by_cache")
     cache.spill!
     @by_reg.delete(r)
     # FIXME: BUG workaround? (was on one line)
@@ -213,9 +213,9 @@ def mark_dirty(reg,  block)
     r.spill = block if r
   end
 
-  def debug_is_register?(reg)
+  def debug_is_register?(reg, where)
     return if reg && reg.to_sym == @selfreg
-    raise "NOT A REGISTER: #{reg.to_s}" if !reg || !@registers.member?(reg.to_sym)
+    raise "NOT A REGISTER: #{reg.inspect} in #{where}" if !reg || !@registers.member?(reg.to_sym)
   end
 
   # Called to "cache" a variable in a register. If no register is
@@ -238,7 +238,7 @@ def cache_reg!(var)
     end
 
     if free
-      debug_is_register?(free)
+      debug_is_register?(free, "cache_reg!")
       c = Cache.new(free,var)
       k = var.to_sym
       @cached[k] = c
@@ -267,7 +267,7 @@ def lock_reg(reg)
   # Low level
   def free!(free)
     @allocated_registers.delete(free)
-    debug_is_register?(free)
+    debug_is_register?(free, "free!")
     @free_registers << free
   end
 
@@ -290,14 +290,17 @@ def with_register(required_reg = nil)
       # registers is in use as cache, see if we can evict one of
       # them.
 
-      if !@cached.empty?
+      if @cached.empty?
+        #STDERR.puts "No cached registers?"
+      else
         # Figure out which register to drop, based on order.
         # (least frequently used variable evicted first)
         r = @order.reverse
         r.each do |v|
           # @FIXME: Workaround for @bug below
           if !free
             c = @cached[v]
+            #STDERR.puts "c: #{c.inspect}"
             if c
               if !c.locked
                 # @FIXME
@@ -316,8 +319,6 @@ def with_register(required_reg = nil)
       end
     end
 
-    debug_is_register?(free)
-
     if !free
       # This really should not happen, unless we are
       # very careless about #with_register blocks.
@@ -331,6 +332,8 @@ def with_register(required_reg = nil)
       1/0
     end
 
+    debug_is_register?(free, "with_register")
+
     # This is for debugging of the allocator - we store
     # a backtrace of where in the compiler the allocation
     # was attempted from in case we run out of registers