Add sema checks for calls to functions taking static array parameters

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@142157 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 2662a19691023abc2fd364393e1281e4f312bb1d..33175a29e5e75ebf960790a49022fd891f6ca48d 100644 (file)
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2716,6 +2716,9 @@ def ext_typecheck_zero_array_size : Extension<
   "zero size arrays are an extension">;
 def err_typecheck_zero_array_size : Error<
   "zero-length arrays are not permitted in C++">;
+def warn_typecheck_zero_static_array_size : Warning<
+  "'static' has no effect on zero-length arrays">,
+  InGroup<DiagGroup<"array-bounds">>;
 def err_at_least_one_initializer_needed_to_size_array : Error<
   "at least one initializer value required to size array">;
 def err_array_size_non_int : Error<"size of array has non-integer type %0">;
@@ -4509,6 +4512,11 @@ def warn_format_mix_positional_nonpositional_args : Warning<
 def warn_null_arg : Warning<
   "null passed to a callee which requires a non-null argument">,
   InGroup<NonNull>;
+def warn_static_array_too_small : Warning<
+  "array argument is too small; contains %0 elements, callee requires at least %1">,
+  InGroup<DiagGroup<"array-bounds">>;
+def note_callee_static_array : Note<
+  "callee declares array parameter as static here">;
 def warn_empty_format_string : Warning<
   "format string is empty">, InGroup<FormatZeroLength>;
 def warn_format_string_is_wide_literal : Warning<

diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 775dc1283d130cbe5e088a6525a8c85f72a19f95..4f244db73778ed485b4c8eb59a8434262bde4467 100644 (file)
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -6103,6 +6103,10 @@ private:
                              const Expr * const *ExprArgs,
                              SourceLocation CallSiteLoc);
 
+  void CheckStaticArrayArguments(const FunctionDecl *FDecl,
+                                 const Expr * const *ExprArgs,
+                                 SourceLocation CallSiteLoc);
+
   void CheckPrintfScanfArguments(const CallExpr *TheCall, bool HasVAListArg,
                                  unsigned format_idx, unsigned firstDataArg,
                                  bool isPrintf);

diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 310138354bb95ea96bbbbbfa92f10a87596b1a89..329adf89e8ad88ad13228e1dad9bfb98a5f44a45 100644 (file)
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -360,6 +360,9 @@ bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) {
                           TheCall->getCallee()->getLocStart());
   }
 
+  CheckStaticArrayArguments(FDecl, TheCall->getArgs(),
+                            TheCall->getCallee()->getLocStart());
+
   // Builtin handling
   int CMF = -1;
   switch (FDecl->getBuiltinID()) {
@@ -1362,6 +1365,64 @@ Sema::CheckNonNullArguments(const NonNullAttr *NonNull,
   }
 }
 
+static void DiagnoseCalleeStaticArrayParam(Sema &S, ParmVarDecl *PVD) {
+  TypeLoc TL = PVD->getTypeSourceInfo()->getTypeLoc();
+  if (ArrayTypeLoc *ATL = dyn_cast<ArrayTypeLoc>(&TL))
+    S.Diag(PVD->getLocation(), diag::note_callee_static_array)
+      << ATL->getLocalSourceRange();
+}
+
+/// CheckStaticArrayArguments - Check that each argument corresponding to a
+/// static array parameter is non-null, and that if it is formed by
+/// array-to-pointer decay, the underlying array is sufficiently large.
+///
+/// C99 6.7.5.3p7: If the keyword static also appears within the [ and ] of the
+/// array type derivation, then for each call to the function, the value of the
+/// corresponding actual argument shall provide access to the first element of
+/// an array with at least as many elements as specified by the size expression.
+void
+Sema::CheckStaticArrayArguments(const FunctionDecl *FDecl,
+                                const Expr * const *ExprArgs,
+                                SourceLocation CallSiteLoc) {
+  // Static array parameters are not supported in C++.
+  if (getLangOptions().CPlusPlus)
+    return;
+
+  for (FunctionDecl::param_const_iterator i = FDecl->param_begin(),
+       e = FDecl->param_end(); i != e; ++i, ++ExprArgs) {
+    const Expr *ArgExpr = *ExprArgs;
+    QualType OrigTy = (*i)->getOriginalType();
+
+    const ArrayType *AT = Context.getAsArrayType(OrigTy);
+    if (!AT || AT->getSizeModifier() != ArrayType::Static)
+      continue;
+
+    if (ArgExpr->isNullPointerConstant(Context,
+                                       Expr::NPC_NeverValueDependent)) {
+      Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange();
+      DiagnoseCalleeStaticArrayParam(*this, *i);
+      continue;
+    }
+
+    const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT);
+    if (!CAT)
+      continue;
+
+    const ConstantArrayType *ArgCAT =
+      Context.getAsConstantArrayType(ArgExpr->IgnoreParenImpCasts()->getType());
+    if (!ArgCAT)
+      continue;
+
+    if (ArgCAT->getSize().ult(CAT->getSize())) {
+      Diag(CallSiteLoc, diag::warn_static_array_too_small)
+        << ArgExpr->getSourceRange()
+        << (unsigned) ArgCAT->getSize().getZExtValue()
+        << (unsigned) CAT->getSize().getZExtValue();
+      DiagnoseCalleeStaticArrayParam(*this, *i);
+    }
+  }
+}
+
 /// CheckPrintfScanfArguments - Check calls to printf and scanf (and similar
 /// functions) for correct use of format strings.
 void

diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index d3a39967de662be35fb27465ddccee35331d665b..fe5b71959192478cf7a3ebbfeffb43e8a64c099b 100644 (file)
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -1315,6 +1315,13 @@ QualType Sema::BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
            isSFINAEContext()? diag::err_typecheck_zero_array_size
                             : diag::ext_typecheck_zero_array_size)
         << ArraySize->getSourceRange();
+
+      if (ASM == ArrayType::Static) {
+        Diag(ArraySize->getLocStart(),
+             diag::warn_typecheck_zero_static_array_size)
+          << ArraySize->getSourceRange();
+        ASM = ArrayType::Normal;
+      }
     } else if (!T->isDependentType() && !T->isVariablyModifiedType() && 
                !T->isIncompleteType()) {
       // Is the array too large?      

diff --git a/test/Sema/static-array.c b/test/Sema/static-array.c
new file mode 100644 (file)
index 0000000..2d4b968
--- /dev/null
+++ b/test/Sema/static-array.c
@@ -0,0 +1,31 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+void cat0(int a[static 0]) {} // expected-warning {{'static' has no effect on zero-length arrays}}
+
+void cat(int a[static 3]) {} // expected-note 2 {{callee declares array parameter as static here}}
+
+typedef int i3[static 3];
+void tcat(i3 a) {}
+
+void vat(int i, int a[static i]) {} // expected-note {{callee declares array parameter as static here}}
+
+void f(int *p) {
+  int a[2], b[3], c[4];
+
+  cat0(0);
+
+  cat(0); // expected-warning {{null passed to a callee which requires a non-null argument}}
+  cat(a); // expected-warning {{array argument is too small; contains 2 elements, callee requires at least 3}}
+  cat(b);
+  cat(c);
+  cat(p);
+
+  tcat(0); // expected-warning {{null passed to a callee which requires a non-null argument}}
+  tcat(a); // expected-warning {{array argument is too small; contains 2 elements, callee requires at least 3}}
+  tcat(b);
+  tcat(c);
+  tcat(p);
+
+  vat(1, 0); // expected-warning {{null passed to a callee which requires a non-null argument}}
+  vat(3, b);
+}