Merge pull request #2808 from kugelfuhr/kugelfuhr/flowanalysis

Simple flow analysis to find unreachable code

test/misc/Makefile

@@ -152,6 +152,36 @@ $(WORKDIR)/bug2655.$1.$2.prg: bug2655.c $(ISEQUAL) | $(WORKDIR)
 	$(CC65) -t sim$2 -$1 -o $$@ $$< $(NULLOUT) 2>$(WORKDIR)/bug2655.$1.$2.out
 	$(ISEQUAL) $(WORKDIR)/bug2655.$1.$2.out bug2655.ref
 
+$(WORKDIR)/flow-do-01.$1.$2.prg: flow-do-01.c $(ISEQUAL) | $(WORKDIR)
+	$(if $(QUIET),echo misc/flow-do-01.$1.$2.prg)
+	$(CC65) -t sim$2 -$1 -o $$@ $$< $(NULLOUT) 2>$(WORKDIR)/flow-do-01.$1.$2.out
+	$(ISEQUAL) $(WORKDIR)/flow-do-01.$1.$2.out flow-do-01.ref
+
+$(WORKDIR)/flow-if-01.$1.$2.prg: flow-if-01.c $(ISEQUAL) | $(WORKDIR)
+	$(if $(QUIET),echo misc/flow-if-01.$1.$2.prg)
+	$(CC65) -t sim$2 -$1 -o $$@ $$< $(NULLOUT) 2>$(WORKDIR)/flow-if-01.$1.$2.out
+	$(ISEQUAL) $(WORKDIR)/flow-if-01.$1.$2.out flow-if-01.ref
+
+$(WORKDIR)/flow-if-02.$1.$2.prg: flow-if-02.c $(ISEQUAL) | $(WORKDIR)
+	$(if $(QUIET),echo misc/flow-if-02.$1.$2.prg)
+	$(CC65) -t sim$2 -$1 -o $$@ $$< $(NULLOUT) 2>$(WORKDIR)/flow-if-02.$1.$2.out
+	$(ISEQUAL) $(WORKDIR)/flow-if-02.$1.$2.out flow-if-02.ref
+
+$(WORKDIR)/flow-switch-01.$1.$2.prg: flow-switch-01.c $(ISEQUAL) | $(WORKDIR)
+	$(if $(QUIET),echo misc/flow-switch-01.$1.$2.prg)
+	$(CC65) -t sim$2 -$1 -o $$@ $$< $(NULLOUT) 2>$(WORKDIR)/flow-switch-01.$1.$2.out
+	$(ISEQUAL) $(WORKDIR)/flow-switch-01.$1.$2.out flow-switch-01.ref
+
+$(WORKDIR)/flow-while-01.$1.$2.prg: flow-while-01.c $(ISEQUAL) | $(WORKDIR)
+	$(if $(QUIET),echo misc/flow-while-01.$1.$2.prg)
+	$(CC65) -t sim$2 -$1 -o $$@ $$< $(NULLOUT) 2>$(WORKDIR)/flow-while-01.$1.$2.out
+	$(ISEQUAL) $(WORKDIR)/flow-while-01.$1.$2.out flow-while-01.ref
+
+$(WORKDIR)/flow-while-02.$1.$2.prg: flow-while-02.c $(ISEQUAL) | $(WORKDIR)
+	$(if $(QUIET),echo misc/flow-while-02.$1.$2.prg)
+	$(CC65) -t sim$2 -$1 -o $$@ $$< $(NULLOUT) 2>$(WORKDIR)/flow-while-02.$1.$2.out
+	$(ISEQUAL) $(WORKDIR)/flow-while-02.$1.$2.out flow-while-02.ref
+
 $(WORKDIR)/limits.$1.$2.prg: limits.c $(ISEQUAL) | $(WORKDIR)
 	$(if $(QUIET),echo misc/limits.$1.$2.prg)
 	$(CC65) -t sim$2 -$1 -o $$(@:.prg=.s) $$< $(NULLOUT) $(CATERR)

test/misc/bug2655.ref

@@ -1,2 +1,2 @@
-bug2655.c:5: Warning: Unreachable code
-bug2655.c:12: Warning: Unreachable code
+bug2655.c:6: Warning: Unreachable code
+bug2655.c:13: Warning: Unreachable code

test/misc/flow-do-01.c

@@ -0,0 +1,87 @@
+int a;
+
+static int f1(void)
+{
+    do {
+        return a;
+    } while (a == 2);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f2(void)
+{
+    do {
+        return a;
+    } while (1);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f3(void)
+{
+    do {
+        return a;
+    } while (0);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f4(void)
+{
+    do {
+        continue;       /* Turns do/while into an endless loop */
+    } while (0);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f5(void)
+{
+    do {
+        if (a == 2) {
+            break;
+        }
+        return a;
+    } while (0);
+    /* Reachable */
+    a = 2;
+    return a;
+}
+
+static int f6(void)
+{
+    do {
+        if (a == 2) {
+            break;
+        }
+        continue;
+    } while (0);
+    /* Reachable */
+    a = 2;
+    return a;
+}
+
+static int f7(void)
+{
+    do {
+        if (a == 2) {
+            return a;
+        } else {
+            continue;
+        }
+    } while (1);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+int main(void)
+{
+    return f1() + f2() + f3() + f4() + f5() + f6() + f7();
+}
+

test/misc/flow-do-01.ref

@@ -0,0 +1,5 @@
+flow-do-01.c:9: Warning: Unreachable code
+flow-do-01.c:19: Warning: Unreachable code
+flow-do-01.c:29: Warning: Unreachable code
+flow-do-01.c:39: Warning: Unreachable code
+flow-do-01.c:79: Warning: Unreachable code

test/misc/flow-if-01.c

@@ -0,0 +1,62 @@
+int a, b;
+
+static int f1(void)
+{
+    if (a == 1) {
+        return 1;
+    }
+    /* Reachable */
+    a = 2;
+    return a;
+}
+
+static int f2(void)
+{
+    if (a == 1) {
+        a = 2;
+    } else {
+        return 1;
+    }
+    /* Reachable */
+    return a;
+}
+
+static int f3(void)
+{
+    if (a == 1) {
+        return 1;
+    } else {
+        a = 2;
+    }
+    /* Reachable */
+    return a;
+}
+
+static int f4(void)
+{
+    if (a == 1) {
+        return 1;
+    } else {
+        return 0;
+    }
+    /* Unreachable */
+    a = 2;
+}
+
+static int f5(void)
+{
+    if (1) {
+        return 1;
+    } else {
+        /* Unreachable */
+        return 0;
+    }
+    /* Unreachable */
+    a = 2;
+}
+
+int main(void)
+{
+    return f1() + f2() + f3() + f4() + f5();
+}
+

test/misc/flow-if-01.ref

@@ -0,0 +1,3 @@
+flow-if-01.c:43: Warning: Unreachable code
+flow-if-01.c:52: Warning: Unreachable code
+flow-if-01.c:55: Warning: Unreachable code

test/misc/flow-if-02.c

@@ -0,0 +1,49 @@
+int a, b;
+
+static int f1(void)
+{
+    if (0) {
+        /* Unreachable but no warning */
+    } else {
+        a = 2;
+    }
+    return a;
+}
+
+static int f2(void)
+{
+    if (0) {
+        /* Unreachable */
+        a = 1;
+    } else {
+        a = 2;
+    }
+    return a;
+}
+
+static int f3(void)
+{
+    if (1) {
+        a = 2;
+    } else {
+        /* Unreachable but no warning */
+    }
+    return a;
+}
+
+static int f4(void)
+{
+    if (1) {
+        a = 2;
+    } else {
+        /* Unreachable */
+        a = 1;
+    }
+    return a;
+}
+
+int main(void)
+{
+    return f1() + f2() + f3() + f4();
+}
+

test/misc/flow-if-02.ref

@@ -0,0 +1,2 @@
+flow-if-02.c:17: Warning: Unreachable code
+flow-if-02.c:40: Warning: Unreachable code

test/misc/flow-switch-01.c

@@ -0,0 +1,68 @@
+int a;
+
+static int f1(void)
+{
+    switch (a) {
+        /* Unreachable */
+        a = 3;
+        case 1:
+            a = 2;
+            break;
+        case 2:
+            a = 1;
+            break;
+        default:
+            a = 0;
+            break;
+    }
+    /* Reachable */
+    return a;
+}
+
+static int f2(void)
+{
+    switch (a) {
+        /* Reachable */
+L:      a = 3;
+        case 1:
+            goto L;
+        case 2:
+            a = 1;
+            break;
+        default:
+            a = 0;
+            break;
+    }
+    /* Reachable */
+    return a;
+}
+
+static int f3(void)
+{
+    switch (a) {
+        case 1:         return a;
+        case 2:         return a+1;
+        default:        return a+2;
+    }
+    /* Unreachable but no warning */
+    return a;
+}
+
+static int f4(void)
+{
+    switch (a) {
+        /* No warning */
+        do {
+            case 1:         ++a; continue;
+            case 2:         return a+1;
+            default:        return a+2;
+        } while (1);
+    }
+    /* Unreachable but no warning */
+    return a;
+}
+
+int main(void)
+{
+    return f1() + f2() + f3() + f4();
+}

test/misc/flow-switch-01.ref

@@ -0,0 +1 @@
+flow-switch-01.c:7: Warning: Unreachable code

test/misc/flow-while-01.c

@@ -0,0 +1,70 @@
+int a;
+
+static int f1(void)
+{
+    while (1) {
+        ++a;
+    }
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f2(void)
+{
+    while (1) {
+        ++a;
+        if (a == 5) break;
+    }
+    /* Reachable */
+    a = 2;
+    return a;
+}
+
+static int f3(void)
+{
+    while (1) {
+        ++a;
+        return a;
+    }
+    /* Unreachable */
+    a = 2;
+}
+
+static int f4(void)
+{
+    while (0) {
+        /* Unreachable */
+        ++a;
+        return a;
+    }
+    /* Reachable */
+    a = 2;
+    return 0;
+}
+
+static int f5(void)
+{
+    while (1) {
+        ++a;
+        if (a == 4) goto L;
+        return a;
+    }
+    /* Reachable via L */
+L:  a = 2;
+}
+
+static int f6(void)
+{
+    while (0) {
+        /* Unreachable but no warning */
+    }
+    a = 2;
+    return a;
+}
+
+int main(void)
+{
+    return f1() + f2() + f3() + f4() + f5() + f6();
+}
+

test/misc/flow-while-01.ref

@@ -0,0 +1,3 @@
+flow-while-01.c:9: Warning: Unreachable code
+flow-while-01.c:31: Warning: Unreachable code
+flow-while-01.c:38: Warning: Unreachable code

test/misc/flow-while-02.c

@@ -0,0 +1,74 @@
+int a;
+
+static int f1(void)
+{
+    while (1) {
+        while (0) {
+            /* Unreachable */
+            ++a;
+        }
+    }
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f2(void)
+{
+    while (1) {
+        do {
+            return a;
+        } while (0);
+        /* Unreachable */
+        break;
+    }
+    /* Unreachable but no warning */
+    a = 2;
+    return a;
+}
+
+static int f3(void)
+{
+    do {
+        while (1) {
+            break;
+        }
+    } while (1);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f4(void)
+{
+    do {
+        while (1) {
+            return a;
+        }
+    } while (0);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f5(void)
+{
+    do {
+        do {
+            if (a == 2) {
+                return a;
+            } else {
+                continue;
+            }
+        } while (0);
+    } while (0);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+int main(void)
+{
+    return f1()/ + f2() + f3() + f4() + f5();
+}
+

test/misc/flow-while-02.ref

@@ -0,0 +1,6 @@
+flow-while-02.c:8: Warning: Unreachable code
+flow-while-02.c:12: Warning: Unreachable code
+flow-while-02.c:23: Warning: Unreachable code
+flow-while-02.c:38: Warning: Unreachable code
+flow-while-02.c:50: Warning: Unreachable code
+flow-while-02.c:66: Warning: Unreachable code

test/misc/goto.ref

@@ -1,4 +1,9 @@
+goto.c:3: Warning: Unreachable code
 goto.c:8: Warning: Goto at line 8 to label start jumps into a block with initialization of an object that has automatic storage duration
+goto.c:17: Warning: Unreachable code
+goto.c:38: Warning: Unreachable code
+goto.c:59: Warning: Unreachable code
+goto.c:80: Warning: Unreachable code
 goto.c:97: Warning: Variable 'a' is defined but never used
 goto.c:117: Warning: Variable 'a' is defined but never used
 goto.c:137: Warning: Variable 'a' is defined but never used
@@ -9,6 +14,7 @@ goto.c:159: Warning: Goto at line 86 to label l8 jumps into a block with initial
 goto.c:159: Warning: Goto at line 106 to label l8 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:159: Warning: Goto at line 126 to label l8 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:159: Warning: Goto at line 146 to label l8 jumps into a block with initialization of an object that has automatic storage duration
+goto.c:161: Warning: Unreachable code
 goto.c:180: Warning: Goto at line 24 to label l9 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:180: Warning: Goto at line 45 to label l9 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:180: Warning: Goto at line 66 to label l9 jumps into a block with initialization of an object that has automatic storage duration
@@ -17,6 +23,7 @@ goto.c:180: Warning: Goto at line 107 to label l9 jumps into a block with initia
 goto.c:180: Warning: Goto at line 127 to label l9 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:180: Warning: Goto at line 147 to label l9 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:180: Warning: Goto at line 168 to label l9 jumps into a block with initialization of an object that has automatic storage duration
+goto.c:182: Warning: Unreachable code
 goto.c:201: Warning: Goto at line 25 to label la jumps into a block with initialization of an object that has automatic storage duration
 goto.c:201: Warning: Goto at line 46 to label la jumps into a block with initialization of an object that has automatic storage duration
 goto.c:201: Warning: Goto at line 67 to label la jumps into a block with initialization of an object that has automatic storage duration
@@ -26,6 +33,7 @@ goto.c:201: Warning: Goto at line 128 to label la jumps into a block with initia
 goto.c:201: Warning: Goto at line 148 to label la jumps into a block with initialization of an object that has automatic storage duration
 goto.c:201: Warning: Goto at line 169 to label la jumps into a block with initialization of an object that has automatic storage duration
 goto.c:201: Warning: Goto at line 190 to label la jumps into a block with initialization of an object that has automatic storage duration
+goto.c:203: Warning: Unreachable code
 goto.c:221: Warning: Goto at line 26 to label lb jumps into a block with initialization of an object that has automatic storage duration
 goto.c:221: Warning: Goto at line 47 to label lb jumps into a block with initialization of an object that has automatic storage duration
 goto.c:221: Warning: Goto at line 68 to label lb jumps into a block with initialization of an object that has automatic storage duration
@@ -57,6 +65,7 @@ goto.c:263: Warning: Goto at line 193 to label ld jumps into a block with initia
 goto.c:263: Warning: Goto at line 214 to label ld jumps into a block with initialization of an object that has automatic storage duration
 goto.c:263: Warning: Goto at line 234 to label ld jumps into a block with initialization of an object that has automatic storage duration
 goto.c:263: Warning: Goto at line 254 to label ld jumps into a block with initialization of an object that has automatic storage duration
+goto.c:265: Warning: Unreachable code
 goto.c:271: Warning: Goto at line 271 to label l8 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:272: Warning: Goto at line 272 to label l9 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:273: Warning: Goto at line 273 to label la jumps into a block with initialization of an object that has automatic storage duration
@@ -75,6 +84,7 @@ goto.c:284: Warning: Goto at line 215 to label le jumps into a block with initia
 goto.c:284: Warning: Goto at line 235 to label le jumps into a block with initialization of an object that has automatic storage duration
 goto.c:284: Warning: Goto at line 255 to label le jumps into a block with initialization of an object that has automatic storage duration
 goto.c:284: Warning: Goto at line 277 to label le jumps into a block with initialization of an object that has automatic storage duration
+goto.c:286: Warning: Unreachable code
 goto.c:292: Warning: Goto at line 292 to label l8 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:293: Warning: Goto at line 293 to label l9 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:294: Warning: Goto at line 294 to label la jumps into a block with initialization of an object that has automatic storage duration
@@ -94,6 +104,7 @@ goto.c:305: Warning: Goto at line 236 to label lf jumps into a block with initia
 goto.c:305: Warning: Goto at line 256 to label lf jumps into a block with initialization of an object that has automatic storage duration
 goto.c:305: Warning: Goto at line 278 to label lf jumps into a block with initialization of an object that has automatic storage duration
 goto.c:305: Warning: Goto at line 299 to label lf jumps into a block with initialization of an object that has automatic storage duration
+goto.c:307: Warning: Unreachable code
 goto.c:313: Warning: Goto at line 313 to label l8 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:314: Warning: Goto at line 314 to label l9 jumps into a block with initialization of an object that has automatic storage duration
 goto.c:315: Warning: Goto at line 315 to label la jumps into a block with initialization of an object that has automatic storage duration