fix continue: jump to conditions not to "do"

Author: mdodovic

MJCompiler/src/rs/ac/bg/etf/pp1/CodeGenerator.java

@@ -24,6 +24,7 @@
 import rs.ac.bg.etf.pp1.ast.DesignatorStatement;
 import rs.ac.bg.etf.pp1.ast.DivideOp;
 import rs.ac.bg.etf.pp1.ast.DoWhileDummyConditionEnd;
+import rs.ac.bg.etf.pp1.ast.DoWhileDummyConditionStart;
 import rs.ac.bg.etf.pp1.ast.DoWhileDummyStart;
 import rs.ac.bg.etf.pp1.ast.EqualOp;
 import rs.ac.bg.etf.pp1.ast.ExprListAddOpTerm;
@@ -982,9 +983,15 @@ public void visit(MulOpFactorList mulOpFactorList) {
 // do-while start instruction (for the purpose of returning back to the beginning of the do-while
 private Stack<Integer> startDoWhileBlockAddressForPatchingStack = new Stack<Integer>(); 
 
-// the last instruction in the "then" block is unconditionally jump which will skip whole else part
+// break in do-while will immediately stop its execution and jump to the very first instruction after whole do-while statement
+// this will save addresses for patch when this address is found
 private Stack<List<Integer>> endDoWhileBlockAddressPatchingFromBreakStatementStack = new Stack<List<Integer>>(); 
 
+// continue in do-while will immediately jump to the condition check (very first instruction of the condition check)
+// this will save addresses for patch when this address is found
+private Stack<List<Integer>> startDoWhileConditionBlockAddressPatchingFromContinueStatementStack = new Stack<List<Integer>>(); 
+
+
 @Override
 public void visit(DoWhileDummyStart DoWhileDummyStart) {
 // open new do-while scope by pushing new list of addresses for patching on stack
@@ -993,7 +1000,22 @@ public void visit(DoWhileDummyStart DoWhileDummyStart) {
 
 // add "do" address
 startDoWhileBlockAddressForPatchingStack.push(Code.pc);
+
 endDoWhileBlockAddressPatchingFromBreakStatementStack.push(new ArrayList<Integer>());
+startDoWhileConditionBlockAddressPatchingFromContinueStatementStack.push(new ArrayList<Integer>());
+
+}
+
+@Override
+public void visit(DoWhileDummyConditionStart DoWhileDummyConditionStart) {
+
+// fix all jumps from continue to the conditions check
+
+for(int placeForPatch: startDoWhileConditionBlockAddressPatchingFromContinueStatementStack.peek()) {
+Code.fixup(placeForPatch);
+}
+
+startDoWhileConditionBlockAddressPatchingFromContinueStatementStack.peek().clear(); // all addresses has been patched so nothing should left
 
 
 }
@@ -1185,6 +1207,7 @@ public void visit(StatementDoWhile StatementDoWhile) {
 destinationAddressPatchingFromORConditionBlockStack.pop();
 startDoWhileBlockAddressForPatchingStack.pop();
 endDoWhileBlockAddressPatchingFromBreakStatementStack.pop();
+startDoWhileConditionBlockAddressPatchingFromContinueStatementStack.pop();
 }
 
 
@@ -1205,10 +1228,11 @@ public void visit(StatementBreak StatementBreak) {
 @Override
 public void visit(StatementContinue StatementContinue) {
 
-// continue represents unconditionally jump to the first instruction in the (deepest) do-while statement
-
-Code.putJump(this.startDoWhileBlockAddressForPatchingStack.peek());
+// continue represents unconditionally jump to the first instruction of the condition in the (deepest) do-while statement
 
+Code.putJump(0); 
+startDoWhileConditionBlockAddressPatchingFromContinueStatementStack.peek().add(Code.pc - 2); // saved address for patching
+
 }
 }
 

MJCompiler/test/program.mj

@@ -1,95 +1,18 @@
 program ABC
 
 {
-bool verify() {
-return true;
-}
-
-void main() int x, y, n; int inv_max; {
 
-if(verify() && x == 0) {
-x = 1;
-print('t');
-print(eol);
-} else
-x = -1;
+void main() int x; int i; {
 
-	if(x == 1) 
-y = 2;
-else 
-y = 3;
-print('y');
-print(y);
-print(eol);
-
-if(x > 0 && y < 2) 
-x = 2;
-print('x');
-print(x);
-print(eol);
-
-if(x >= 0 || y <= 2) 
-x = 3;
-print('x');
-print(x);
-print(eol);
-
-if(x != 0 && y >= 2 || x == 1) 
-x = 4;
-print('x');
-print(x);
-print(eol);
-
-if(-x > y) {
-inv_max = -x;
-print('>');
-} else {
-if(x == y) {
-inv_max = -1;
-print('=');
-} else {
-inv_max = -y;
-print('<');
-}
-}
-print(eol);
-print('-'); print('m'); print('a'); print('x'); print(inv_max);
-
-print(eol);
-print(x);
-print(eol);
-n = -11;
-do { 
-n++;
-
-if(-5 <= n && n <= -3){
-if(n == -5) {
-print('p');
-} else if(n == -4) {
-print('c');
-} else {
-print('t');
-}
+i = 1;
+do{
+if(i % 2 == 0) {
+i++;
+continue; 
 }
-
-if(x - 1 + n - 3 == 0) {
-print('x');
-break;
-}
-if(n == -2) {
-print(' '); print('n'); print('e'); print('g');
-print(eol);
-continue;
-}
-print(n);
-print(eol);
-
-
-} while (n <= x);
-
-print(n);
-print(eol);
-
+print('i'); print(i); print(eol);
+i++;
+}while(i<=6);
 
 }
 }

MJCompiler/test/program.obj

@@ -30,7 +30,7 @@ public static void main(String[] args) throws Exception {
 Reader br = null;
 try {
 
-String mjFileName = "controll_structures";
+String mjFileName = "program";
 
 File sourceCode = new File("test/" + mjFileName + ".mj");
 //	File sourceCode = new File("test/class_extends.mj");