% -*- mode: latex; auto-revert-interval: 0.5 -*-

\begin{tikzpicture}[->,>=stealth',shorten >=1pt,auto, node distance=4em,
                   very thin,font={\scriptsize\bf}]

  % ===================
  % global declarations
  % ===================
                   
  \pgfdeclarelayer{background}
  \pgfdeclarelayer{foreground}
  \pgfsetlayers{background,main,foreground}

  \tikzstyle{basic-block} = [draw=black!50, fill=white, rectangle, minimum width=12.5em]
  \ifthenelse{\boolean{preview}}
    {\tikzstyle{block} = [basic-block]}
    {\tikzstyle{block} = [basic-block, drop shadow]}

  \tikzstyle{enter} = [block, ellipse, fill=red!20]
  \tikzstyle{guard} = [block, fill=yellow!20]
  \tikzstyle{newguard} = [block, fill=green!20]
  \tikzstyle{lbl} = [font={\scriptsize\it}, minimum width=0em]

  \provideboolean{loop-virtuals-step1}
  \provideboolean{loop-virtuals-step2}
  \provideboolean{loop-virtuals-step3}

  %\setboolean{loop-virtuals-step1}{true}

  \ifthenelse{\boolean{loop-virtuals-step1} \or \boolean{loop-virtuals-step2}} {
    \clip (-3.9, 1.7) rectangle (2.7,-7.6);
  } {}

  \ifthenelse{\boolean{loop-virtuals-step3}} {
    \clip (-2.7, 0.5) rectangle (10.4,-7.4);
  } {}


  % =========================================
  % unoptimized trace (only in step 1)
  % =========================================

  \ifthenelse{\boolean{loop-virtuals-step1}} {

    \node[enter, name=start] {loop($obj_0$)} ;
    \node[guard, name=block1, below of=start] {
      \begin{tabular}{c}
        guard\_class($obj_0$, \texttt{W\_Int}) \\
        $val_0$ = getfield\_gc($obj_0$, \texttt{val}) \\
        $nextval_0$ = int\_sub($val_0$, $1$) \\
      \end{tabular}
    };

    \node[guard, name=block2, below of=block1, node distance=4em] {
      \begin{tabular}{c}
        $obj_1$ = new\_with\_vtable(\texttt{W\_Int}) \\
        setfield\_gc($obj_1$, $nextval_0$, \texttt{val}) \\
      \end{tabular}
    };

    \node[guard, name=block3, below of=block2, node distance=5em] { 
      \begin{tabular}{c}
        guard\_class($obj_1$, \texttt{W\_Int}) \\
        $val_1$ = getfield\_gc($obj_1$, \texttt{val}) \\
        $t_0$ = int\_gt($val_1$, 0) \\
        guard\_true($t_0$) \\
        jump($obj_1$)
      \end{tabular}
    };
  
    \path (start.south) edge (block1.north) ;
    \path (block1.south) edge (block2.north) ;
    \path (block2.south) edge (block3.north) ;
    \path (block3.south) 
              edge[out distance=19em, in distance=19em, out=230, in=130] 
          (start.north) ;

  } {} % end if

  % =========================================
  % entry bridge (only in step 3)
  % =========================================

  \ifthenelse{\boolean{loop-virtuals-step3}} {

    \node[enter, name=start, fill=blue!20] {entry\_bridge($obj_0$)} ;
    \node[guard, name=block1, below of=start] {
      \begin{tabular}{c}
        guard\_class($obj_0$, \texttt{W\_Int}) \\
        $val_0$ = getfield\_gc($obj_0$, \texttt{val}) \\
        $nextval_0$ = int\_sub($val_0$, $1$) \\
      \end{tabular}
    };

    \node[guard, name=block2, below=2em of block1] {
      \begin{tabular}{c}
        $t_0$ = int\_gt($nextval_0$, 0) \\
        guard\_true($t_0$) \\
      \end{tabular}
    };

    \node[guard, name=block3, below=2em of block2] { 
      \begin{tabular}{c}
        jump($nextval_0$)
      \end{tabular}
    };
  
    \path (start.south) edge (block1.north) ;
    \path (block1.south) edge (block2.north) ;
    \path (block2.south) edge (block3.north) ;
  } {} % end if


  % =========================================
  % optimized trace (only in steps 2 and 3)
  % =========================================

  \ifthenelse{\boolean{loop-virtuals-step2}} {
    \node[enter, name=start_opt] {loop($obj\_val_0$)} ;
  } {}
  \ifthenelse{\boolean{loop-virtuals-step3}} {
    % in step 3, we want the loop to start below the entry bridge
    \node[enter, name=start_opt, below right=4em and 7em of start] {loop($obj\_val_0$)} ;
  }

  \ifthenelse{\boolean{loop-virtuals-step2} \or \boolean{loop-virtuals-step3}} {
    \node[guard, name=block_opt1, below of=start_opt] {
      \begin{tabular}{c}
        $obj\_val_1$ = int\_sub($obj\_val_0$, $1$) \\
      \end{tabular}
    };

    \node[guard, name=block_opt2, below of=block_opt1, node distance=4em] {
      \begin{tabular}{c}
        $t_1$ = int\_gt($obj\_val_1$, 0) \\
        guard\_true($t_1$) \\
        jump($obj\_val_1$)
      \end{tabular}
    };
  
    \path (start_opt.south) edge (block_opt1.north) ;
    \path (block_opt1.south) edge (block_opt2.north) ;
  } {}

  \ifthenelse{\boolean{loop-virtuals-step2}} {
    \path (block_opt2.south) 
              edge[out distance=17em, in distance=17em, out=230, in=130]
          (start_opt.north) ;
  } {}
  \ifthenelse{\boolean{loop-virtuals-step3}} {
    \path (block_opt2.south) 
              edge[out distance=17em, in distance=17em, out=310, in=50]
          (start_opt.north) ;
  } {}


  % =========================================
  % step 3: entry bridge --> optimized loop
  % =========================================

  \ifthenelse{\boolean{loop-virtuals-step3}} {
    \path (block3.south) 
              edge[out distance=19em, in distance=19em, out=320, in=130]
          (start_opt.north);
  } {}

\end{tikzpicture}