Merge pull request #14444 from alexet/range-cases

CPP: Add some range analysis cases

cpp/ql/test/library-tests/ir/range-analysis/SimpleRangeAnalysis_tests.cpp

@@ -1028,4 +1028,75 @@ void test_negate_signed(int s) {
   if(10 < s && s < 20) {
     range<int>(-s); // $ range=<=-11 range=>=-19
   }
-}
+}
+
+// By setting the guard after the use in another guard we 
+// don't get the useful information
+void test_guard_after_use(int pos, int size, int offset) {
+  if (pos + offset >= size) { // $ overflow=+-
+    return;
+  }
+  if (offset != 1) {
+    return;
+  }
+  range(pos + 1); // $ overflow=+ range="==InitializeParameter: pos+1" MISSING: range="<=InitializeParameter: size-1"
+} 
+
+int cond();
+
+
+// This is basically what we get when we have a loop that calls 
+// realloc in some iterations
+void alloc_in_loop(int origLen) {
+  if (origLen <= 10) {
+    return;
+  }
+  int len = origLen;
+  int index = 0;
+  while (cond()) {
+    if (index == len) {
+      if (len >= 1000) {
+        return;
+      }
+      len = len * 2; // $ overflow=-
+    }
+    // We want that index < len
+    range(index); // $ MISSING: range="<=InitializeParameter: len-1"
+    index++;
+  }
+}
+
+// This came from a case where it handled the leftovers before an unrolled loop 
+void mask_at_start(int len) {
+  if (len < 0) {
+    return;
+  }
+  int leftOver = len & 63; 
+  for (int i = 0; i < leftOver; i++) {
+    range(i); // $ range=<=62 range=>=0  range="<=Store: ... & ... | Store: leftOver-1" range="<=InitializeParameter: len-1"
+  }
+  // Do something with leftOver
+  for (int index = leftOver; index < len; index+=64) {
+    range(index);  // $ range="<=InitializeParameter: len-1"
+    // This should be in bounds
+    range(index + 16); // $ range="<=InitializeParameter: len+15" range="==Phi: index+16" MISSING: range="<=InitializeParameter: len-1"
+  }
+}
+
+
+// Same as above but with modulo
+void mod_at_start(int len) {
+  if (len < 0) {
+    return;
+  }
+  int leftOver = len % 64;
+  for (int i = 0; i < leftOver; i++) {
+    range(i); // $ range=<=62 range=>=0  range="<=Store: ... % ... | Store: leftOver-1"  range="<=InitializeParameter: len-1"
+  }
+  // Do something with leftOver
+  for (int index = leftOver; index < len; index+=64) {
+    range(index);  // $ range="<=InitializeParameter: len-1"
+    // This should be in bounds 
+    range(index + 16); // $ range="<=InitializeParameter: len+15" range="==Phi: index+16" MISSING: range="<=InitializeParameter: len-49"
+  }
+}