Fixed some some Div/Mod issues in x86

Author: crzysdrs

src/codegen/Assembly.java

@@ -127,6 +127,18 @@ public void unspill(int free) {
         }
     }
 
+    public int spillTo(int free, String target_reg) {
+        int orig_free = free;
+        while (!target_reg.equals(reg(free))) {
+            spill(++free);
+        }
+        return free;
+    }
+    public void unspillTo(int free, int orig_free) {
+        while (free > orig_free) {
+            unspill(free--);
+        }
+    }
     public void spillAll(int free) {
         int toSpill = Math.min(free, numRegs - 1);
         for (int i = 1; i <= toSpill; i++) {
@@ -180,14 +192,14 @@ public void loadThis(int size, int free) {
     public void loadTmp(int x86_tmp, int free) {
         out.println("// Attempting to load " + x86_tmp + " into " + free);
         int diff = free - x86_tmp;
-        if (diff >= numRegs) {
-            emit("movl", indirect((free - x86_tmp) * 4, "%esp"), reg(free));
-        } else if (diff > 0) {
+        if (diff < 0) {
+            assert(false); /* reg is higher on stack ? */
+        } else if (diff < numRegs) {
             emit("movl", reg(x86_tmp), reg(free));
-        } else if (diff == 0) {
-            /* same register ? */
+        } else if (diff > 0) {
+            emit("movl", indirect(diff * WORDSIZE, "%esp"), reg(free));
         } else {
-            assert(false); /* cannot reference a tmp that doesn't exist */
+            /* same register ? */
         }
     }
     //- emit individual instructions, with varying numbers of arguments ------

src/syntax/ArrayLiteral.java

@@ -94,7 +94,9 @@ public Type typeOf(Context ctxt, VarEnv env)
      *  leave the result in the specified free variable.
      */
     public void compileExpr(Assembly a, int free) {
+        a.emit("//compiling tmp to " + free);
         this.object.compileExpr(a, free);
+        a.emit("//setting tmp to " + free);
         tmp.setTmp(free);
         a.spill(free + 1);
         for (Expression e : inits) {

src/syntax/DivExpr.java

@@ -42,21 +42,16 @@ boolean commutes() {
      *  leave the result in the specified free variable.
      */
     public void compileExpr(Assembly a, int free) {
-        int orig_free = free;
-        while (!a.reg(free).equals("%eax")) {
-            free++;
-        }
-        a.spill(free);
-        left.compileExpr(a, free);
-        a.spill(free + 1);
-        right.compileExpr(a, free + 1);
+        int freed = a.spillTo(free, "%eax");
+        left.compileExpr(a, freed);
+        a.spill(freed + 1);
+        right.compileExpr(a, freed + 1);
         a.emit("movl", a.immed(0), "%edx");
-        a.emit("idivl", a.reg(free + 1));
-
+        a.emit("idivl", a.reg(freed + 1));
         /* hiding %eax into %edx in case overwritten by spills */
         a.emit("movl", "%eax", "%edx");
-        /* %edx will not be touched by this */
-        a.unspillAll(orig_free);
+        /* %edx will not be touched by this unspill */
+        a.unspillTo(freed + 1, free);
         a.emit("movl", "%edx", a.reg(free));
     }
 

src/syntax/ModExpr.java

@@ -42,19 +42,15 @@ boolean commutes() {
      *  leave the result in the specified free variable.
      */
     public void compileExpr(Assembly a, int free) {
-        int orig_free = free;
-        while (!a.reg(free).equals("%eax")) {
-            free++;
-        }
-        a.spill(free);
-        left.compileExpr(a, free);
-        a.spill(free + 1);
-        right.compileExpr(a, free + 1);
+        int freed = a.spillTo(free, "%eax");
+        left.compileExpr(a, freed);
+        a.spill(freed + 1);
+        right.compileExpr(a, freed + 1);
         a.emit("movl", a.immed(0), "%edx");
-        a.emit("idivl", a.reg(free + 1));
+        a.emit("idivl", a.reg(freed + 1));
 
         /* %edx will not be touched by this */
-        a.unspillAll(orig_free);
+        a.unspillTo(freed + 1, free);
         a.emit("movl", "%edx", a.reg(free));
     }
 

src/syntax/TmpAccess.java

@@ -58,6 +58,7 @@ public void setTmp(int free) {
      *  leave the result in the specified free variable.
      */
     public void compileExpr(Assembly a, int free) {
+        //a.emit("int", "$3");
         a.loadTmp(x86_tmp, free);
     }
 

unitTests/arraylit3.gcc.ref

@@ -0,0 +1,23 @@
+class Main {
+    static void main() {
+        int [][] test2 = new int[][] {
+            new int[]{2147483647 / 2 / 2 / 2 / 2 / 2 / 2 / 2 / 2 / 2 / 2 / 2, 2, 3, 4, 5, 6},
+            new int[]{1, 2, 3},
+            new int[]{9, 2, 3, 4},
+            new int[]{},
+            new int[]{1, 2, 3, 4, 5, 6, 7, 8}
+        };
+        int x = 0;
+        while (x < test2.length) {
+            int y = 0;
+            while (y < test2[x].length) {
+                System.out.print(Integer.toString(test2[x][y]));
+                System.out.print(" ");
+                y = y + 1;
+            }
+            System.out.println("");
+            x = x + 1;
+        }
+    }
+}
+

unitTests/arraylit3.j

@@ -0,0 +1 @@
+Writing LLVM Bitcode to build/test/arraylit3.bc

unitTests/arraylit3.mjc.ref

@@ -0,0 +1,5 @@
+1048575 2 3 4 5 6 
+1 2 3 
+9 2 3 4 
+
+1 2 3 4 5 6 7 8