From: Michael D. Lowis <mike.lowis@gentex.com>
Date: Tue, 30 Nov 2021 15:15:22 +0000 (-0500)
Subject: implemented topological sort and fixed up plantuml graph dumping to use it. Next... 
X-Git-Url: https://git.mdlowis.com/?a=commitdiff_plain;h=82018c9281ad787ecc60edcffefb801116c5dc22;p=proto%2Fobnc.git

implemented topological sort and fixed up plantuml graph dumping to use it. Next step is finishing SSA creation and printing for if statements
---

diff --git a/cerise/src/grammar.c b/cerise/src/grammar.c
index cfc8e59..221ed7a 100644
--- a/cerise/src/grammar.c
+++ b/cerise/src/grammar.c
@@ -413,7 +413,6 @@ static SsaBlock* statement_seq(Parser* p)
             SsaNode* cond = expression(p);
             check_bool(p, cond);
             expect(p, THEN);
-            SsaNode* ssa_if(p, cond);
 
             SsaBlock* block = p->curr_block;
             block->links[0] = statement_seq(p);
diff --git a/cerise/src/ssa.c b/cerise/src/ssa.c
index 60a1897..c99bd50 100644
--- a/cerise/src/ssa.c
+++ b/cerise/src/ssa.c
@@ -184,6 +184,7 @@ void ssa_block_add(SsaBlock* blk, SsaNode* node)
 
 SsaNode* ssa_if(Parser* p, SsaNode* cond, SsaBlock* br1, SsaBlock* br2)
 {
+    (void)br1, (void)br2;
     cond = load(p, cond);
     return NULL;
 }
@@ -529,62 +530,72 @@ void ssa_print_block(Parser* p, Bitset* set, SsaBlock* block)
     }
 }
 
-static void print_block_graph(Parser* p, Bitset* set, SsaBlock* block)
+static void topsort(Bitset* set, SsaBlock** sorted, SsaBlock* block)
 {
-    if (bitset_has(set, block->id))
+    if (block && !bitset_has(set, block->id))
     {
-        return;
+        /* mark it visited and visit children */
+        bitset_add(set, block->id);
+        topsort(set, sorted, block->links[1]);
+        topsort(set, sorted, block->links[0]);
+
+        /* push block to the sorted list */
+        block->next = *sorted;
+        *sorted = block;
     }
-    bitset_add(set, block->id);
+}
 
-    /* print the phis */
-    for (SsaPhi* phi = block->phis; phi; phi = phi->next)
+void ssa_print_graph(Parser* p, SsaBlock* block)
+{
+    /* perform a topological sort of the nodes */
+    SsaBlock* sorted = NULL;
+    Bitset* set = bitset_new(p->blockid);
+    topsort(set, &sorted, block);
+
+
+    /* now let's print the plantuml representation */
+    printf("@startuml\n");
+    printf("[*] --> block%lu\n", block->id);
+    for (SsaBlock* curr = sorted; curr; curr = curr->next)
     {
-        Symbol* s = symbol_getbyid(p, phi->symid);
-        s->version++;
-        printf("block%lu: %s.%lu = phi(", block->id, s->name, s->version);
-        for (SsaPhiVar* var = phi->vars; var; var = var->next)
+
+        /* print the phis */
+        for (SsaPhi* phi = block->phis; phi; phi = phi->next)
         {
-            printf("%s.%lu", s->name, var->version);
-            if (var->next)
+            Symbol* s = symbol_getbyid(p, phi->symid);
+            s->version++;
+            printf("block%lu: %s.%lu = phi(", curr->id, s->name, s->version);
+            for (SsaPhiVar* var = phi->vars; var; var = var->next)
             {
-                printf(", ");
+                printf("%s.%lu", s->name, var->version);
+                if (var->next)
+                {
+                    printf(", ");
+                }
             }
+            puts(")");
         }
-        puts(")");
-    }
-
-    /* print the instructions */
-    for (SsaNode* node = block->head; node; node = node->next)
-    {
-        printf("block%lu : ", block->id);
-        print_dest(p, node);
-        ssa_print(p, node);
-        puts("");
-    }
 
-    /* print the next nodes */
-    if (block->links[0])
-    {
-        printf("block%lu --> block%lu\n", block->id, block->links[0]->id);
-        print_block_graph(p, set, block->links[0]);
-    }
+        /* print the instructions */
+        for (SsaNode* node = curr->head; node; node = node->next)
+        {
+            printf("block%lu : ", curr->id);
+            print_dest(p, node);
+            ssa_print(p, node);
+            puts("");
+        }
 
-    if (block->links[1])
-    {
-        printf("block%lu --> block%lu\n", block->id, block->links[1]->id);
-//        if (!block->links[1]->phis)
+        /* print the links */
+        if (curr->links[1])
         {
-            print_block_graph(p, set, block->links[1]);
+            printf("block%lu --> block%lu\n", curr->id, curr->links[1]->id);
+        }
+        if (curr->links[0])
+        {
+            printf("block%lu --> block%lu\n", curr->id, curr->links[0]->id);
         }
-    }
-}
 
-void ssa_print_graph(Parser* p, SsaBlock* block)
-{
-    printf("@startuml\n");
-    printf("[*] --> block%lu\n", block->id);
-    Bitset* set = bitset_new(p->blockid);
-    print_block_graph(p, set, block);
+        puts("");
+    }
     printf("@enduml\n");
 }