nitvm: Utility class for printing basic blocks and SSA to dot files

Signed-off-by: Julien Pagès <julien.projet@gmail.com>

diff --git a/src/ssa.nit b/src/ssa.nit
index b0e1bbe..a45ac5b 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
 
@@ -510,6 +513,57 @@ 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`