tree.c

#include "defs.h"
#include "data.h"
#include "decl.h"

// AST tree functions
// Copyright (c) 2019 Warren Toomey, GPL3

// Build and return a generic AST node
struct ASTnode *mkastnode(int op, int type,
			  struct ASTnode *left,
			  struct ASTnode *mid,
			  struct ASTnode *right, int intvalue) {
  struct ASTnode *n;

  // Malloc a new ASTnode
  n = (struct ASTnode *) malloc(sizeof(struct ASTnode));
  if (n == NULL)
    fatal("Unable to malloc in mkastnode()");

  // Copy in the field values and return it
  n->op = op;
  n->type = type;
  n->left = left;
  n->mid = mid;
  n->right = right;
  n->v.intvalue = intvalue;
  return (n);
}


// Make an AST leaf node
struct ASTnode *mkastleaf(int op, int type, int intvalue) {
  return (mkastnode(op, type, NULL, NULL, NULL, intvalue));
}

// Make a unary AST node: only one child
struct ASTnode *mkastunary(int op, int type, struct ASTnode *left,
			    int intvalue) {
  return (mkastnode(op, type, left, NULL, NULL, intvalue));
}

// Generate and return a new label number
// just for AST dumping purposes
static int gendumplabel(void) {
  static int id = 1;
  return (id++);
}

// Given an AST tree, print it out and follow the
// traversal of the tree that genAST() follows
void dumpAST(struct ASTnode *n, int label, int level) {
  int Lfalse, Lstart, Lend;


  switch (n->op) {
  case A_IF:
    Lfalse = gendumplabel();
    for (int i = 0; i < level; i++)
      fprintf(stdout, " ");
    fprintf(stdout, "A_IF");
    if (n->right) {
      Lend = gendumplabel();
      fprintf(stdout, ", end L%d", Lend);
    }
    fprintf(stdout, "\n");
    dumpAST(n->left, Lfalse, level + 2);
    dumpAST(n->mid, NOLABEL, level + 2);
    if (n->right)
      dumpAST(n->right, NOLABEL, level + 2);
    return;
  case A_WHILE:
    Lstart = gendumplabel();
    for (int i = 0; i < level; i++)
      fprintf(stdout, " ");
    fprintf(stdout, "A_WHILE, start L%d\n", Lstart);
    Lend = gendumplabel();
    dumpAST(n->left, Lend, level + 2);
    dumpAST(n->right, NOLABEL, level + 2);
    return;
  }

  // Reset level to -2 for A_GLUE
  if (n->op == A_GLUE)
    level = -2;

  // General AST node handling
  if (n->left)
    dumpAST(n->left, NOLABEL, level + 2);
  if (n->right)
    dumpAST(n->right, NOLABEL, level + 2);


  for (int i = 0; i < level; i++)
    fprintf(stdout, " ");
  switch (n->op) {
  case A_GLUE:
    fprintf(stdout, "\n\n");
    return;
  case A_FUNCTION:
    fprintf(stdout, "A_FUNCTION %s\n", Symtable[n->v.id].name);
    return;
  case A_ADD:
    fprintf(stdout, "A_ADD\n");
    return;
  case A_SUBTRACT:
    fprintf(stdout, "A_SUBTRACT\n");
    return;
  case A_MULTIPLY:
    fprintf(stdout, "A_MULTIPLY\n");
    return;
  case A_DIVIDE:
    fprintf(stdout, "A_DIVIDE\n");
    return;
  case A_EQ:
    fprintf(stdout, "A_EQ\n");
    return;
  case A_NE:
    fprintf(stdout, "A_NE\n");
    return;
  case A_LT:
    fprintf(stdout, "A_LE\n");
    return;
  case A_GT:
    fprintf(stdout, "A_GT\n");
    return;
  case A_LE:
    fprintf(stdout, "A_LE\n");
    return;
  case A_GE:
    fprintf(stdout, "A_GE\n");
    return;
  case A_INTLIT:
    fprintf(stdout, "A_INTLIT %d\n", n->v.intvalue);
    return;
  case A_STRLIT:
    fprintf(stdout, "A_STRLIT rval label L%d\n", n->v.id);
    return;
  case A_IDENT:
    if (n->rvalue)
      fprintf(stdout, "A_IDENT rval %s\n", Symtable[n->v.id].name);
    else
      fprintf(stdout, "A_IDENT %s\n", Symtable[n->v.id].name);
    return;
  case A_ASSIGN:
    fprintf(stdout, "A_ASSIGN\n");
    return;
  case A_WIDEN:
    fprintf(stdout, "A_WIDEN\n");
    return;
  case A_RETURN:
    fprintf(stdout, "A_RETURN\n");
    return;
  case A_FUNCCALL:
    fprintf(stdout, "A_FUNCCALL %s\n", Symtable[n->v.id].name);
    return;
  case A_ADDR:
    fprintf(stdout, "A_ADDR %s\n", Symtable[n->v.id].name);
    return;
  case A_DEREF:
    if (n->rvalue)
      fprintf(stdout, "A_DEREF rval\n");
    else
      fprintf(stdout, "A_DEREF\n");
    return;
  case A_SCALE:
    fprintf(stdout, "A_SCALE %d\n", n->v.size);
    return;
  case A_PREINC:
    fprintf(stdout, "A_PREINC %s\n", Symtable[n->v.id].name);
    return;
  case A_PREDEC:
    fprintf(stdout, "A_PREDEC %s\n", Symtable[n->v.id].name);
    return;
  case A_POSTINC:
    fprintf(stdout, "A_POSTINC\n");
    return;
  case A_POSTDEC:
    fprintf(stdout, "A_POSTDEC\n");
    return;
  case A_NEGATE:
    fprintf(stdout, "A_NEGATE\n");
    return;
  default:
    fatald("Unknown dumpAST operator", n->op);
  }
}