Add -Wloop-analysis. This warning will fire on for loops which the variables

in the loop conditional do not change.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155835 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 146 insertions, 0 deletions

diff --git a/test/SemaCXX/warn-loop-analysis.cpp b/test/SemaCXX/warn-loop-analysis.cpp
new file mode 100644
index 0000000000..802ce52c4e
--- /dev/null
+++ b/test/SemaCXX/warn-loop-analysis.cpp
@@ -0,0 +1,146 @@
+// RUN: %clang_cc1 -fsyntax-only -Wloop-analysis -verify %s
+
+struct S {
+  bool stop() { return false; }
+  bool keep_running;
+};
+
+void by_ref(int &value) { }
+void by_value(int value) { }
+void by_pointer(int *value) {}
+
+void test1() {
+  S s;
+  for (; !s.stop();) {}
+  for (; s.keep_running;) {}
+  for (int i; i < 1; ++i) {}
+  for (int i; i < 1; ) {}  // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (int i; i < 1; ) { ++i; }
+  for (int i; i < 1; ) { return; }
+  for (int i; i < 1; ) { break; }
+  for (int i; i < 1; ) { goto exit_loop; }
+exit_loop:
+  for (int i; i < 1; ) { by_ref(i); }
+  for (int i; i < 1; ) { by_value(i); }  // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (int i; i < 1; ) { by_pointer(&i); }
+
+  for (int i; i < 1; ++i)
+    for (int j; j < 1; ++j)
+      { }
+  for (int i; i < 1; ++i)
+    for (int j; j < 1; ++i)  // expected-warning {{variable 'j' used in loop condition not modified in loop body}}
+      { }
+  for (int i; i < 1; ++i)
+    for (int j; i < 1; ++j)  // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+      { }
+
+  for (int *i, *j; i < j; ++i) {}
+  for (int *i, *j; i < j;) {}  // expected-warning {{variables 'i' and 'j' used in loop condition not modified in loop body}}
+
+  // Dereferencing pointers is ignored for now.
+  for (int *i; *i; ) {}
+}
+
+void test2() {
+  int i, j, k;
+  int *ptr;
+
+  // Testing CastExpr
+  for (; i; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; i; ) { i = 5; }
+
+  // Testing BinaryOperator
+  for (; i < j; ) {} // expected-warning {{variables 'i' and 'j' used in loop condition not modified in loop body}}
+  for (; i < j; ) { i = 5; }
+  for (; i < j; ) { j = 5; }
+
+  // Testing IntegerLiteral
+  for (; i < 5; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; i < 5; ) { i = 5; }
+
+  // Testing FloatingLiteral
+  for (; i < 5.0; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; i < 5.0; ) { i = 5; }
+
+  // Testing CharacterLiteral
+  for (; i == 'a'; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; i == 'a'; ) { i = 5; }
+
+  // Testing CXXBoolLiteralExpr
+  for (; i == true; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; i == true; ) { i = 5; }
+
+  // Testing GNUNullExpr
+  for (; ptr == __null; ) {} // expected-warning {{variable 'ptr' used in loop condition not modified in loop body}}
+  for (; ptr == __null; ) { ptr = &i; }
+
+  // Testing UnaryOperator
+  for (; -i > 5; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; -i > 5; ) { ++i; }
+
+  // Testing ImaginaryLiteral
+  for (; i != 3i; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; i != 3i; ) { ++i; }
+
+  // Testing ConditionalOperator
+  for (; i ? j : k; ) {} // expected-warning {{variables 'i' 'j' and 'k' used in loop condition not modified in loop body}}
+  for (; i ? j : k; ) { ++i; }
+  for (; i ? j : k; ) { ++j; }
+  for (; i ? j : k; ) { ++k; }
+  for (; i; ) { j = i ? i : i; }  // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; i; ) { j = (i = 1) ? i : i; }
+  for (; i; ) { j = i ? i : ++i; }
+
+  // Testing BinaryConditionalOperator
+  for (; i ?: j; ) {} // expected-warning {{variables 'i' and 'j' used in loop condition not modified in loop body}}
+  for (; i ?: j; ) { ++i; }
+  for (; i ?: j; ) { ++j; }
+  for (; i; ) { j = i ?: i; }  // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+
+  // Testing ParenExpr
+  for (; (i); ) { }  // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; (i); ) { ++i; }
+
+  // Testing non-evaluated variables
+  for (; i < sizeof(j); ) { }  // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; i < sizeof(j); ) { ++j; }  // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
+  for (; i < sizeof(j); ) { ++i; }
+}
+
+// False positive and how to silence.
+void test3() {
+  int x;
+  int *ptr = &x;
+  for (;x<5;) { *ptr = 6; }  // expected-warning {{variable 'x' used in loop condition not modified in loop body}}
+
+  for (;x<5;) {
+    *ptr = 6;
+    (void)x;
+  }
+}
+
+// Check ordering and printing of variables.  Max variables is currently 4.
+void test4() {
+  int a, b, c, d, e, f;
+  for (; a;);  // expected-warning {{variable 'a' used in loop condition not modified in loop body}}
+  for (; a + b;);  // expected-warning {{variables 'a' and 'b' used in loop condition not modified in loop body}}
+  for (; a + b + c;);  // expected-warning {{variables 'a' 'b' and 'c' used in loop condition not modified in loop body}}
+  for (; a + b + c + d;);  // expected-warning {{variables 'a' 'b' 'c' and 'd' used in loop condition not modified in loop body}}
+  for (; a + b + c + d + e;);  // expected-warning {{variables used in loop condition not modified in loop body}}
+  for (; a + b + c + d + e + f;);  // expected-warning {{variables used in loop condition not modified in loop body}}
+  for (; a + c + d + b;);  // expected-warning {{variables 'a' 'c' 'd' and 'b' used in loop condition not modified in loop body}}
+  for (; d + c + b + a;);  // expected-warning {{variables 'd' 'c' 'b' and 'a' used in loop condition not modified in loop body}}
+}
+
+// Ensure that the warning doesn't fail when lots of variables are used
+// in the conditional.
+void test5() {
+  for (int a; a+a+a+a+a+a+a+a+a+a;); // \
+   // expected-warning {{variable 'a' used in loop condition not modified in loop body}}
+  for (int a; a+a+a+a+a+a+a+a+a+a+a;); // \
+   // expected-warning {{variable 'a' used in loop condition not modified in loop body}}
+  for (int a; a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a;);  // \
+   // expected-warning {{variable 'a' used in loop condition not modified in loop body}}
+  for (int a; a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a;);//\
+   // expected-warning {{variable 'a' used in loop condition not modified in loop body}}
+}