cfg.c

#include <stdlib.h>
#include <stdint.h>

struct CFGBlock;

typedef struct {
  struct CFGBlock *source;
  struct CFGBlock *destination;
} CFGEdge;

typedef struct CFGBlock {

  Instruction *instructions;
  int numInstructions;

  CFGEdge *successors;
  int numSuccessors;

  CFGEdge *predecessors;
  int numPredecessors;

  int blockID;
} CFGBlock;

typedef struct {
  CFGBlock **cfgBlocks;
  int numBlocks;
} ControlFlowGraph;

CFGBlock createCFGBlock(void) {
  CFGBlock block;

  block.instructions = NULL;
  block.numInstructions = 0;
  block.successors = NULL;
  block.numSuccessors = 0;
  block.predecessors = NULL;
  block.numPredecessors = 0;
  block.blockID = -1;
  return block;
}

ControlFlowGraph createControlFlowGraph(void) {
  ControlFlowGraph cfg;

  cfg.cfgBlocks = NULL;
  cfg.numBlocks = 0;
  return cfg;
}

void addEdge(CFGBlock *source, CFGBlock *destination) {

  source->successors = zRealloc(source->successors,
                               (source->numSuccessors + 1) * sizeof(CFGEdge));
  source->successors[source->numSuccessors].source = source;
  source->successors[source->numSuccessors].destination = destination;
  source->numSuccessors++;

  destination->predecessors =
      zRealloc(destination->predecessors,
              (destination->numPredecessors + 1) * sizeof(CFGEdge));
  destination->predecessors[destination->numPredecessors].source = source;
  destination->predecessors[destination->numPredecessors].destination =
      destination;
  destination->numPredecessors++;
}

void initializeCFG(ControlFlowGraph *cfg) {
  cfg->cfgBlocks = zAlloc(2 * sizeof(CFGBlock));

  cfg->cfgBlocks[0] = createCFGBlock();
  cfg->cfgBlocks[1] = createCFGBlock();

  cfg->cfgBlocks[0].blockID = 0;
  cfg->cfgBlocks[1].blockID = 1;

  addEdge(&cfg.cfgBlocks[0], &cfg.cfgBlocks[1]);

  cfg->numBlocks = 2;
}