[SSA] Fix up to_ssa.py and add test cases

bril-ts/brili.ts

@@ -53,7 +53,7 @@ export class Heap<X> {
         return this.storage.size == 0;
     }
 
-    private count = 0;
+    private count = 1;
     private getNewBase():number {
         let val = this.count;
         this.count++;
@@ -64,19 +64,33 @@ export class Heap<X> {
         return;
     }
 
+    private getNullKey(): Key {
+      return new Key(0, 0);
+    }
+
+    private isNull(key: Key): boolean {
+      return key.base == 0;
+    }
+
     alloc(amt:number): Key {
-        if (amt <= 0) {
+        if (amt < 0) {
             throw error(`cannot allocate ${amt} entries`);
         }
-        let base = this.getNewBase();
-        this.storage.set(base, new Array(amt))
-        return new Key(base, 0);
+        if (amt == 0) {
+          return this.getNullKey();
+        } else {
+          let base = this.getNewBase();
+          this.storage.set(base, new Array(amt))
+          return new Key(base, 0);
+        }
     }
 
     free(key: Key) {
         if (this.storage.has(key.base) && key.offset == 0) {
             this.freeKey(key);
             this.storage.delete(key.base);
+        } else if (this.isNull(key) && key.offset == 0) {
+            // no-op
         } else {
             throw error(`Tried to free illegal memory location base: ${key.base}, offset: ${key.offset}. Offset must be 0.`);
         }
@@ -205,7 +219,7 @@ function findFunc(func: bril.Ident, funcs: readonly bril.Function[]) {
 function alloc(ptrType: bril.ParamType, amt:number, heap:Heap<Value>): Pointer {
   if (typeof ptrType != 'object') {
     throw error(`unspecified pointer type ${ptrType}`);
-  } else if (amt <= 0) {
+  } else if (amt < 0) {
     throw error(`must allocate a positive amount of memory: ${amt} <= 0`);
   } else {
     let loc = heap.alloc(amt)

brilirs/src/interp.rs

@@ -60,15 +60,29 @@ impl Heap {
     self.memory.is_empty()
   }
 
+  fn null_base(&self) -> usize {
+    0
+  }
+
+  fn is_null(&self, key: &Pointer) -> bool {
+    key.base == self.null_base()
+  }
+
   fn alloc(&mut self, amount: i64, ptr_type: bril_rs::Type) -> Result<Value, InterpError> {
     if amount < 0 {
       return Err(InterpError::CannotAllocSize(amount));
     }
-    let base = self.base_num_counter;
-    self.base_num_counter += 1;
-    self
-      .memory
-      .insert(base, vec![Value::default(); amount as usize]);
+    let base = if amount > 0 {
+      // Add first to reserve base == 0 for null
+      self.base_num_counter += 1;
+      let base = self.base_num_counter;
+      self
+        .memory
+        .insert(base, vec![Value::default(); amount as usize]);
+      base
+    } else {
+      self.null_base()
+    };
     Ok(Value::Pointer(Pointer {
       base,
       offset: 0,
@@ -77,7 +91,10 @@ impl Heap {
   }
 
   fn free(&mut self, key: Pointer) -> Result<(), InterpError> {
-    if self.memory.remove(&key.base).is_some() && key.offset == 0 {
+    if self.is_null(&key) && key.offset == 0 {
+      // no-op
+      Ok(())
+    } else if self.memory.remove(&key.base).is_some() && key.offset == 0 {
       Ok(())
     } else {
       Err(InterpError::IllegalFree(key.base, key.offset))

examples/test/from_ssa/argwrite.bril

@@ -0,0 +1,9 @@
+# ARGS: 3
+@main(a: int) {
+  cond: bool = const true;
+  br cond .here .there;
+.here:
+  a: int = const 5;
+.there:
+  print a;
+}

examples/test/from_ssa/argwrite.out

@@ -0,0 +1 @@
+5

examples/test/from_ssa/if-const.bril

@@ -0,0 +1,14 @@
+@main() {
+    cond: bool = const true;
+    br cond .true .false;
+.true:
+    a: int = const 0;
+    jmp .zexit;
+.false:
+    b: int = const 1;
+    jmp .zexit;
+# zexit to trigger a bug in to_ssa.py that depends on
+# the order that basic blocks get renamed.
+.zexit:
+    print a;
+}

examples/test/from_ssa/if-const.out

@@ -0,0 +1 @@
+0

examples/test/from_ssa/if-ssa.bril

@@ -0,0 +1,17 @@
+# ARGS: true
+@main(cond: bool) {
+.entry:
+    a.1: int = const 47;
+    br cond .left .right;
+.left:
+    a.2: int = add a.1 a.1;
+    jmp .zexit;
+.right:
+    a.3: int = mul a.1 a.1;
+    jmp .zexit;
+# zexit to trigger a bug in to_ssa.py that depends on
+# the order that basic blocks get renamed.
+.zexit:
+    a.4: int = phi .left a.2 .right a.3;
+    print a.4;
+}

examples/test/from_ssa/if-ssa.out

@@ -0,0 +1 @@
+94

examples/test/from_ssa/if.bril

@@ -0,0 +1,14 @@
+# ARGS: false
+@main(cond: bool) {
+.entry:
+    a: int = const 47;
+    br cond .left .right;
+.left:
+    a: int = add a a;
+    jmp .exit;
+.right:
+    a: int = mul a a;
+    jmp .exit;
+.exit:
+    print a;
+}

examples/test/from_ssa/if.out

@@ -0,0 +1 @@
+2209

examples/test/from_ssa/loop-branch.bril

@@ -0,0 +1,24 @@
+@func(): int {
+    n: int = const 5;
+    ret n;
+}
+
+@loop(infinite: bool, print: bool) {
+.entry:
+.loop.header:
+    br infinite .loop.body .loop.end;
+.loop.body:
+    br print .loop.print .loop.next;
+.loop.print:
+    v: int = call @func;
+    print v;
+.loop.next:
+    jmp .loop.header;
+.loop.end:
+}
+
+@main() {
+  infinite: bool = const false;
+  print: bool = const true;
+  call @loop infinite print;
+}

examples/test/from_ssa/loop.bril

@@ -0,0 +1,14 @@
+@main {
+.entry:
+    i: int = const 1;
+    jmp .loop;
+.loop:
+    max: int = const 10;
+    cond: bool = lt i max;
+    br cond .body .exit;
+.body:
+    i: int = add i i;
+    jmp .loop;
+.exit:
+    print i;
+}

examples/test/from_ssa/loop.out

@@ -0,0 +1 @@
+16

examples/test/from_ssa/selfloop.bril

@@ -0,0 +1,14 @@
+@main {
+.entry:
+  one: int = const 1;
+  zero: int = const 0;
+  x: int = const 5;
+.loop:
+  x: int = sub x one;
+  done: bool = eq x zero;
+.br:
+  br done .exit .loop;
+.exit:
+  print x;
+  ret;
+}

examples/test/from_ssa/selfloop.out

@@ -0,0 +1 @@
+0

examples/test/from_ssa/turnt.toml

@@ -0,0 +1 @@
+command = "bril2json < {filename} | python ../../to_ssa.py | python ../../from_ssa.py | brili {args}"

examples/test/from_ssa/while.bril

@@ -0,0 +1,13 @@
+# ARGS: 5
+@main(a: int) {
+.while.cond:
+  zero: int = const 0;
+  is_term: bool = eq a zero;
+  br is_term .while.finish .while.body;
+.while.body:
+  one: int = const 1;
+  a: int = sub a one;
+  jmp .while.cond;
+.while.finish:
+  print a;
+}

examples/test/from_ssa/while.out

@@ -0,0 +1 @@
+0

examples/test/to_ssa/argwrite.out

@@ -1,5 +1,7 @@
 @main(a: int) {
 .b1:
+  __undefined.int: int = const 0;
+  __undefined.bool: bool = const false;
   cond.0: bool = const true;
   br cond.0 .here .there;
 .here:

examples/test/to_ssa/if-const.out

@@ -1,5 +1,7 @@
 @main {
 .b1:
+  __undefined.int: int = const 0;
+  __undefined.bool: bool = const false;
   cond.0: bool = const true;
   br cond.0 .true .false;
 .true:
@@ -9,8 +11,8 @@
   b.0: int = const 1;
   jmp .zexit;
 .zexit:
-  b.1: int = phi b.0 b.0 .false .true;
-  a.1: int = phi __undefined a.0 .false .true;
+  b.1: int = phi b.0 __undefined.int .false .true;
+  a.1: int = phi __undefined.int a.0 .false .true;
   print a.1;
   ret;
 }

examples/test/to_ssa/if-ssa.out

@@ -1,5 +1,7 @@
 @main(cond: bool) {
 .entry:
+  __undefined.int: int = const 0;
+  __undefined.bool: bool = const false;
   a.1.0: int = const 47;
   br cond .left .right;
 .left:
@@ -9,8 +11,8 @@
   a.3.0: int = mul a.1.0 a.1.0;
   jmp .zexit;
 .zexit:
-  a.3.1: int = phi __undefined a.3.0 .left .right;
-  a.2.1: int = phi a.2.0 a.2.0 .left .right;
+  a.3.1: int = phi __undefined.int a.3.0 .left .right;
+  a.2.1: int = phi a.2.0 __undefined.int .left .right;
   a.4.0: int = phi a.2.1 a.3.1 .left .right;
   print a.4.0;
   ret;

examples/test/to_ssa/if.out

@@ -1,5 +1,7 @@
 @main(cond: bool) {
 .entry:
+  __undefined.int: int = const 0;
+  __undefined.bool: bool = const false;
   a.0: int = const 47;
   br cond .left .right;
 .left:

examples/test/to_ssa/loop-branch.bril

@@ -0,0 +1,24 @@
+@func(): int {
+    n: int = const 5;
+    ret n;
+}
+
+@loop(infinite: bool, print: bool) {
+.entry:
+.loop.header:
+    br infinite .loop.body .loop.end;
+.loop.body:
+    br print .loop.print .loop.next;
+.loop.print:
+    v: int = call @func;
+    print v;
+.loop.next:
+    jmp .loop.header;
+.loop.end:
+}
+
+@main() {
+  infinite: bool = const false;
+  print: bool = const true;
+  call @loop infinite print;
+}

examples/test/to_ssa/loop-branch.out

@@ -0,0 +1,34 @@
+@func: int {
+.b1:
+  __undefined.int: int = const 0;
+  n.0: int = const 5;
+  ret n.0;
+}
+@loop(infinite: bool, print: bool) {
+.entry:
+  __undefined.int: int = const 0;
+  __undefined.bool: bool = const false;
+  jmp .loop.header;
+.loop.header:
+  v.0: int = phi __undefined.int v.1 .entry .loop.next;
+  br infinite .loop.body .loop.end;
+.loop.body:
+  br print .loop.print .loop.next;
+.loop.print:
+  v.2: int = call @func;
+  print v.2;
+  jmp .loop.next;
+.loop.next:
+  v.1: int = phi v.0 v.2 .loop.body .loop.print;
+  jmp .loop.header;
+.loop.end:
+  ret;
+}
+@main {
+.b1:
+  __undefined.bool: bool = const false;
+  infinite.0: bool = const false;
+  print.0: bool = const true;
+  call @loop infinite.0 print.0;
+  ret;
+}

examples/test/to_ssa/loop.out

@@ -1,11 +1,13 @@
 @main {
 .entry:
+  __undefined.int: int = const 0;
+  __undefined.bool: bool = const false;
   i.0: int = const 1;
   jmp .loop;
 .loop:
-  max.0: int = phi __undefined max.1 .entry .body;
+  max.0: int = phi __undefined.int max.1 .entry .body;
   i.1: int = phi i.0 i.2 .entry .body;
-  cond.0: bool = phi __undefined cond.1 .entry .body;
+  cond.0: bool = phi __undefined.bool cond.1 .entry .body;
   max.1: int = const 10;
   cond.1: bool = lt i.1 max.1;
   br cond.1 .body .exit;

examples/test/to_ssa/selfloop.out

@@ -1,12 +1,14 @@
 @main {
 .entry:
+  __undefined.int: int = const 0;
+  __undefined.bool: bool = const false;
   one.0: int = const 1;
   zero.0: int = const 0;
   x.0: int = const 5;
   jmp .loop;
 .loop:
   x.1: int = phi x.0 x.2 .entry .br;
-  done.0: bool = phi __undefined done.1 .entry .br;
+  done.0: bool = phi __undefined.bool done.1 .entry .br;
   x.2: int = sub x.1 one.0;
   done.1: bool = eq x.2 zero.0;
   jmp .br;