Semantic analysis for C++ reinterpret_cast and const_cast. Patch by Sebastian Redl.

llvm-svn: 58094

3 files changed, 137 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/const-cast.cpp b/clang/test/SemaCXX/const-cast.cpp
new file mode 100644
index 00000000000..90e8ed73789
--- /dev/null
+++ b/clang/test/SemaCXX/const-cast.cpp
@@ -0,0 +1,56 @@
+// RUN: clang -fsyntax-only -verify %s
+
+// See if aliasing can confuse this baby.
+typedef char c;
+typedef c *cp;
+typedef cp *cpp;
+typedef cpp *cppp;
+typedef cppp &cpppr;
+typedef const cppp &cpppcr;
+typedef const char cc;
+typedef cc *ccp;
+typedef volatile ccp ccvp;
+typedef ccvp *ccvpp;
+typedef const volatile ccvpp ccvpcvp;
+typedef ccvpcvp *ccvpcvpp;
+typedef int iar[100];
+typedef iar &iarr;
+typedef int (*f)(int);
+
+char ***good_const_cast_test(ccvpcvpp var)
+{
+  // Cast away deep consts and volatiles.
+  char ***var2 = const_cast<cppp>(var);
+  char ***const &var3 = static_cast<cpppcr>(var2); // Different bug.
+  // Const reference to reference.
+  char ***&var4 = const_cast<cpppr>(var3);
+  // Drop reference. Intentionally without qualifier change.
+  char *** var5 = const_cast<cppp>(var4);
+  const int ar[100] = {0};
+  int (&rar)[100] = const_cast<iarr>(ar); // expected-warning {{statement was disambiguated as declaration}} expected-error {{const_cast from 'int const [100]' to 'iarr' is not allowed}}
+  // Array decay. Intentionally without qualifier change.
+  int *pi = const_cast<int*>(ar);
+  f fp = 0;
+  // Don't misidentify fn** as a function pointer.
+  f *fpp = const_cast<f*>(&fp);
+  return var4;
+}
+
+short *bad_const_cast_test(char const *volatile *const volatile *var)
+{
+  // Different pointer levels.
+  char **var2 = const_cast<char**>(var); // expected-error {{const_cast from 'char const *volatile *const volatile *' to 'char **' is not allowed}}
+  // Different final type.
+  short ***var3 = const_cast<short***>(var); // expected-error {{const_cast from 'char const *volatile *const volatile *' to 'short ***' is not allowed}}
+  // Rvalue to reference.
+  char ***&var4 = const_cast<cpppr>(&var2); // expected-error {{const_cast from rvalue to reference type 'cpppr'}}
+  // Non-pointer.
+  char v = const_cast<char>(**var2); // expected-error {{const_cast to 'char', which is not a reference, pointer-to-object, or pointer-to-data-member}}
+  const int *ar[100] = {0};
+  // Not even lenient g++ accepts this.
+  int *(*rar)[100] = const_cast<int *(*)[100]>(&ar); // expected-error {{const_cast from 'int const *(*)[100]' to 'int *(*)[100]' is not allowed}}
+  f fp1 = 0;
+  // Function pointers.
+  f fp2 = const_cast<f>(fp1); // expected-error {{const_cast to 'f', which is not a reference, pointer-to-object, or pointer-to-data-member}}
+  return **var3;
+}
diff --git a/clang/test/SemaCXX/reinterpret-cast.cpp b/clang/test/SemaCXX/reinterpret-cast.cpp
new file mode 100644
index 00000000000..6172c9f8d9e
--- /dev/null
+++ b/clang/test/SemaCXX/reinterpret-cast.cpp
@@ -0,0 +1,72 @@
+// RUN: clang -fsyntax-only -verify %s
+
+enum test { testval = 1 };
+struct structure { int m; };
+typedef void (*fnptr)();
+
+// Test the conversion to self.
+void self_conversion()
+{
+  // T*->T* is allowed, T->T in general not.
+  int i = 0;
+  (void)reinterpret_cast<int>(i); // expected-error {{reinterpret_cast from 'int' to 'int' is not allowed}}
+  structure s;
+  (void)reinterpret_cast<structure>(s); // expected-error {{reinterpret_cast from 'struct structure' to 'struct structure' is not allowed}}
+  int *pi = 0;
+  (void)reinterpret_cast<int*>(pi);
+}
+
+// Test conversion between pointer and integral types, as in /3 and /4.
+void integral_conversion()
+{
+  void *vp = reinterpret_cast<void*>(testval);
+  long l = reinterpret_cast<long>(vp);
+  (void)reinterpret_cast<float*>(l);
+  fnptr fnp = reinterpret_cast<fnptr>(l);
+  (void)reinterpret_cast<char>(fnp); // expected-error {{cast from pointer to smaller type 'char' loses information}}
+  (void)reinterpret_cast<long>(fnp);
+}
+
+void pointer_conversion()
+{
+  int *p1 = 0;
+  float *p2 = reinterpret_cast<float*>(p1);
+  structure *p3 = reinterpret_cast<structure*>(p2);
+  typedef int **ppint;
+  ppint *deep = reinterpret_cast<ppint*>(p3);
+  (void)reinterpret_cast<fnptr*>(deep);
+}
+
+void constness()
+{
+  int ***const ipppc = 0;
+  // Valid: T1* -> T2 const*
+  int const *icp = reinterpret_cast<int const*>(ipppc);
+  // Invalid: T1 const* -> T2*
+  (void)reinterpret_cast<int*>(icp); // expected-error {{reinterpret_cast from 'int const *' to 'int *' casts away constness}}
+  // Invalid: T1*** -> T2 const* const**
+  int const *const **icpcpp = reinterpret_cast<int const* const**>(ipppc); // expected-error {{reinterpret_cast from 'int ***const' to 'int const *const **' casts away constness}}
+  // Valid: T1* -> T2*
+  int *ip = reinterpret_cast<int*>(icpcpp);
+  // Valid: T* -> T const*
+  (void)reinterpret_cast<int const*>(ip);
+  // Valid: T*** -> T2 const* const* const*
+  (void)reinterpret_cast<int const* const* const*>(ipppc);
+}
+
+void fnptrs()
+{
+  typedef int (*fnptr2)(int);
+  fnptr fp = 0;
+  (void)reinterpret_cast<fnptr2>(fp);
+  void *vp = reinterpret_cast<void*>(fp);
+  (void)reinterpret_cast<fnptr>(vp);
+}
+
+void refs()
+{
+  long l = 0;
+  char &c = reinterpret_cast<char&>(l);
+  // Bad: from rvalue
+  (void)reinterpret_cast<int&>(&c); // expected-error {{reinterpret_cast from rvalue to reference type 'int &'}}
+}
diff --git a/clang/test/SemaCXX/reinterpret-fn-obj-pedantic.cpp b/clang/test/SemaCXX/reinterpret-fn-obj-pedantic.cpp
new file mode 100644
index 00000000000..b39d1f0a69a
--- /dev/null
+++ b/clang/test/SemaCXX/reinterpret-fn-obj-pedantic.cpp
@@ -0,0 +1,9 @@
+// RUN: clang -fsyntax-only -verify -std=c++98 -pedantic %s
+
+void fnptrs()
+{
+  typedef void (*fnptr)();
+  fnptr fp = 0;
+  void *vp = reinterpret_cast<void*>(fp); // expected-warning {{reinterpret_cast between pointer-to-function and pointer-to-object is an extension}}
+  (void)reinterpret_cast<fnptr>(vp); // expected-warning {{reinterpret_cast between pointer-to-function and pointer-to-object is an extension}}
+}