typing: warn about useless null when the target is always `null`

[nit.git] / src / ssa.nit

diff --git a/src/ssa.nit b/src/ssa.nit
index b0e1bbe..634dfa3 100644 (file)
--- a/src/ssa.nit
+++ b/src/ssa.nit
@@ -102,6 +102,9 @@ class BasicBlock
        # Used to handle recursions by treating only one time each block
        var treated: Bool = false
 
+       # Used to dump the BasicBlock to dot
+       var treated_debug: Bool = false
+
        # If true, the iterated dominance frontier of this block has been computed
        var df_computed: Bool = false
 
@@ -205,6 +208,10 @@ redef class APropdef
        # Generate all basic blocks for this code
        fun generate_basic_blocks(ssa: SSA) is abstract
 
+       # Contain all AST-parts related to object mechanisms the propdef has:
+       # instantiation, method dispatch, attribute access, subtyping-test
+       var object_sites: Array[AExpr] = new Array[AExpr]
+
        # Compute the three steps of SSA-algorithm
        # `ssa` A new instance of SSA class initialized with `self`
        fun compute_ssa(ssa: SSA)
@@ -510,6 +517,57 @@ redef class AMethPropdef
        end
 end
 
+# Utility class for dump basic block and SSA output to dot files
+class BlockDebug
+       # The output file
+       var file: FileWriter
+
+       # Dump all the hierarchy of BasicBlock from `block` to the leaves
+       fun dump(block: BasicBlock)
+       do
+               # Write the basic blocks hierarchy in output file
+               file.write("digraph basic_blocks\n\{\n")
+               var i = 0
+               file.write(print_block(block, i))
+               file.write("\n\}")
+
+               file.close
+       end
+
+       # Print all the block recursively from `block` to the leaves
+       # *`block` The root BasicBlock
+       # *`i` Used for the recursion
+       private fun print_block(block: BasicBlock, i: Int): String
+       do
+               # Precise the type and location of the begin and end of current block
+               var s = "block{block.hash.to_s} [shape=record, label="+"\"\{"
+               s += "block" + block.to_s.escape_to_dot
+               s += "|\{" + block.first.location.file.filename.to_s + block.first.location.line_start.to_s
+               s += " | " + block.first.to_s.escape_to_dot
+
+               # Print phi-functions if any
+               for phi in block.phi_functions do
+                       s += " | " + phi.to_s.escape_to_dot + " "
+               end
+
+               s += "}|\{" + block.last.location.file.filename.to_s + block.last.location.line_start.to_s
+               s += " | " + block.last.to_s.escape_to_dot + "}}\"];"+ "\n"
+
+               i += 1
+               block.treated_debug = true
+
+               for b in block.successors do
+                       # Print edges to successors
+                       s += "block{block.hash.to_s} -> " + " block{b.hash.to_s};\n"
+
+                       # Recursively print child blocks
+                       if not b.treated_debug then s += print_block(b, i)
+               end
+
+               return s
+       end
+end
+
 redef class AExpr
        # Generate recursively basic block for this expression
        # *`ssa` An instance of the SSA class initialized with the enclosing `APropdef`
@@ -742,6 +800,8 @@ end
 redef class AIsaExpr
        redef fun generate_basic_blocks(ssa, old_block)
        do
+               ssa.propdef.object_sites.add(self)
+
                return self.n_expr.generate_basic_blocks(ssa, old_block)
        end
 end
@@ -749,6 +809,8 @@ end
 redef class AAsCastExpr
        redef fun generate_basic_blocks(ssa, old_block)
        do
+               ssa.propdef.object_sites.add(self)
+
                return self.n_expr.generate_basic_blocks(ssa, old_block)
        end
 end
@@ -780,6 +842,8 @@ redef class ASendExpr
                # A call does not finish the current block,
                # because we create intra-procedural basic blocks here
 
+               ssa.propdef.object_sites.add(self)
+
                # Recursively goes into arguments to find variables if any
                for e in self.raw_arguments do e.generate_basic_blocks(ssa, old_block)
 
@@ -792,6 +856,8 @@ redef class ASendReassignFormExpr
        do
                self.n_expr.generate_basic_blocks(ssa, old_block)
 
+               ssa.propdef.object_sites.add(self)
+
                # Recursively goes into arguments to find variables if any
                for e in self.raw_arguments do e.generate_basic_blocks(ssa, old_block)
 
@@ -814,6 +880,8 @@ redef class ANewExpr
        do
                for e in self.n_args.n_exprs do e.generate_basic_blocks(ssa, old_block)
 
+               ssa.propdef.object_sites.add(self)
+
                return old_block
        end
 end
@@ -821,6 +889,8 @@ end
 redef class AAttrExpr
        redef fun generate_basic_blocks(ssa, old_block)
        do
+               ssa.propdef.object_sites.add(self)
+
                return self.n_expr.generate_basic_blocks(ssa, old_block)
        end
 end
@@ -828,6 +898,8 @@ end
 redef class AAttrAssignExpr
        redef fun generate_basic_blocks(ssa, old_block)
        do
+               ssa.propdef.object_sites.add(self)
+
                return self.n_expr.generate_basic_blocks(ssa, old_block)
        end
 end
@@ -835,6 +907,8 @@ end
 redef class AAttrReassignExpr
        redef fun generate_basic_blocks(ssa, old_block)
        do
+               ssa.propdef.object_sites.add(self)
+
                return self.n_expr.generate_basic_blocks(ssa, old_block)
        end
 end