1 files changed, 89 insertions, 0 deletions
diff --git a/ssa.c b/ssa.c
new file mode 100644
index 0000000..0db9aaf
--- /dev/null
+++ b/ssa.c
@@ -0,0 +1,89 @@
+#include "ir.h"
+#include <stdint.h>
+
+struct uses *
+ssauses(struct function *fn)
+{
+   extern int ninstr;
+   struct uses *uses = xcalloc(ninstr * sizeof *uses);
+   vec_of(struct use) *vuse = xcalloc(ninstr * sizeof *vuse), useacc = {0};
+   struct block *blk = fn->entry;
+
+   #define USE(r, isjmp, x) do {                       \
+      struct use u0, u = {isjmp, {x}};                 \
+      if ((r).t == RTMP) {                             \
+         if (vuse[(r).i].n == 0){                      \
+            memcpy(&vuse[(r).i].p, &u, sizeof u);      \
+            ++vuse[(r).i].n;                           \
+         } else {                                      \
+            if (vuse[(r).i].n == 1) {                  \
+               memcpy(&u0, &vuse[(r).i].p, sizeof u0); \
+               vuse[(r).i].n = 0;                      \
+               vuse[(r).i].p = 0;                      \
+               vpush(&vuse[(r).i], u0);                \
+            }                                          \
+            vpush(&vuse[(r).i], u);                    \
+         }                                             \
+      }                                                \
+   } while (0)
+
+   do {
+      for (int i = 0; i < blk->phi.n; ++i) {
+         int ins = blk->phi.p[i];
+         struct phi *phi = &phitab.p[instrtab[ins].l.i];
+         for (int i = 0; i < phi->n; ++i) {
+            USE(phi->ref[i], 0, ins);
+         }
+      }
+      for (int i = 0; i < blk->ins.n; ++i) {
+         int ins = blk->ins.p[i];
+         assert(instrtab[ins].l.t != RMORE);
+         if (instrtab[ins].op != Ocall) assert(instrtab[ins].l.t != RMORE);
+         USE(instrtab[ins].l, 0, ins);
+         USE(instrtab[ins].r, 0, ins);
+      }
+      USE(blk->jmp.arg[0], 1, blk->id);
+      USE(blk->jmp.arg[1], 1, blk->id);
+   } while ((blk = blk->lnext) != fn->entry);
+   for (int i = 0; i < ninstr; ++i) {
+      int nuse = uses[i].nuse = vuse[i].n;
+      if (!nuse) continue;
+      if (nuse == 1) {
+         uses[i].use = uses[i]._use0;
+         memcpy(uses[i].use, &vuse[i].p, sizeof *uses[i].use);
+      } else if (nuse < arraylength(uses[i]._use0)) {
+         uses[i].use = uses[i]._use0;
+         memcpy(uses[i].use, vuse[i].p, nuse * sizeof(struct use));
+         vfree(&vuse[i]);
+      } else {
+         intptr_t o;
+         o = useacc.n;
+         memcpy(&uses[i].use, &o, sizeof o);
+         vpushn(&useacc, vuse[i].p, nuse);
+         vfree(&vuse[i]);
+      }
+   }
+   for (int i = 0; i < ninstr; ++i) {
+      if (uses[i].use != uses[i]._use0) {
+         intptr_t o;
+         memcpy(&o, &uses[i].use, sizeof o);
+         uses[i].use = useacc.p + o;
+      }
+   }
+   free(vuse);
+   return uses;
+}
+
+void
+freeuses(struct uses *u, int n)
+{
+   for (int i = 0; i < n; ++i) {
+      if (u[i].use != u[i]._use0) {
+         free(u[i].use);
+         break;
+      }
+   }
+   free(u);
+}
+
+/* vim:set ts=3 sw=3 expandtab: */