c-tree.h (C_DECL_USED, [...]): New.

	* c-tree.h (C_DECL_USED, parser_obstack, in_alignof, in_sizeof,
	in_typeof, record_maybe_used_decl, pop_maybe_used,
	c_expr_sizeof_expr, c_expr_sizeof_type): New.
	* c-decl.c (parser_obstack): New.
	(c_init_decl_processing): Initialize parser_obstack.
	(c_write_global_declarations_1): Check for used but undefined
	static functions.
	* c-parse.in (%union): Add otype.
	(save_obstack_position): New.
	(extdefs): Use it.
	(unary_expr): Update in_sizeof and in_alignof.  Use
	c_expr_sizeof_expr and c_expr_sizeof_type.
	(sizeof): Update in_sizeof.
	(alignof): Update in_alignof.
	(typeof): Update in_typeof.
	(typespec_nonreserved_nonattr): Call pop_maybe_used.
	* c-typeck.c (in_alignof, in_sizeof, in_typeof, struct
	maybe_used_decl, maybe_used_decls, record_maybe_used_decl,
	pop_maybe_used, c_expr_sizeof_expr, c_expr_sizeof_type): New.
	(build_external_ref): Set C_DECL_USED or call
	record_maybe_used_decl if appropriate.
	* toplev.c (check_global_declarations): Check TREE_NO_WARNING.

testsuite:
	* gcc.dg/c90-static-1.c, gcc.dg/c99-static-1.c,
	gcc.dg/gnu99-static-1.c: New tests.

From-SVN: r87216

3 files changed, 87 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/c90-static-1.c b/gcc/testsuite/gcc.dg/c90-static-1.c
new file mode 100644
index 0000000..cc6f320
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c90-static-1.c
@@ -0,0 +1,22 @@
+/* It is a constraint violation for a static function to be declared
+   but not defined if it is used except in a sizeof expression.  The
+   use of the function simply being unevaluated is not enough.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "-O2 -std=iso9899:1990 -pedantic-errors" } */
+
+/* Constraint violation (trivial case, where function is used).  */
+static void f0(void); /* { dg-error "used but never defined" } */
+void g0(void) { f0(); }
+
+/* Constraint violation.  */
+static void f1(void); /* { dg-error "used but never defined" } */
+void g1(void) { if (0) { f1(); } }
+
+/* Constraint violation.  */
+static int f2(void); /* { dg-error "used but never defined" } */
+void g2(void) { 0 ? f2() : 0; }
+
+/* OK.  */
+static int f3(void);
+void g3(void) { sizeof(f3()); }
diff --git a/gcc/testsuite/gcc.dg/c99-static-1.c b/gcc/testsuite/gcc.dg/c99-static-1.c
new file mode 100644
index 0000000..3c817c6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c99-static-1.c
@@ -0,0 +1,35 @@
+/* It is a constraint violation for a static function to be declared
+   but not defined if it is used except in a sizeof expression whose
+   result is an integer constant.  The use of the function simply
+   being unevaluated is not enough.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "-O2 -std=iso9899:1999 -pedantic-errors" } */
+
+/* Constraint violation (trivial case, where function is used).  */
+static void f0(void); /* { dg-error "used but never defined" } */
+void g0(void) { f0(); }
+
+/* Constraint violation.  */
+static void f1(void); /* { dg-error "used but never defined" } */
+void g1(void) { if (0) { f1(); } }
+
+/* Constraint violation.  */
+static int f2(void); /* { dg-error "used but never defined" } */
+void g2(void) { 0 ? f2() : 0; }
+
+/* OK.  */
+static int f3(void);
+void g3(void) { sizeof(f3()); }
+
+/* OK (VM type, not VLA).  */
+static int f4(void);
+void g4(void) { sizeof(int (*)[f4()]); }
+
+/* Constraint violation (VLA).  */
+static int f5(void); /* { dg-error "used but never defined" "VLA" { xfail *-*-* } } */
+void g5(void) { sizeof(int [0 ? f5() : 1]); }
+
+/* OK (non-constant sizeof inside constant sizeof).  */
+static int f6(void);
+void g6(void) { sizeof(sizeof(int [f6()])); }
diff --git a/gcc/testsuite/gcc.dg/gnu99-static-1.c b/gcc/testsuite/gcc.dg/gnu99-static-1.c
new file mode 100644
index 0000000..b600a4b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/gnu99-static-1.c
@@ -0,0 +1,30 @@
+/* It is a constraint violation for a static function to be declared
+   but not defined if it is used except in a sizeof expression whose
+   result is an integer constant.  In GNU C, we need to consider
+   __typeof__ and __alignof__ as well.  __alignof__ always returns a
+   constant, so static functions can always be used therein.
+   __typeof__ evaluates its argument iff it has variably modified
+   type.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "-O2 -std=gnu99 -pedantic-errors" } */
+
+/* __alignof__, OK.  */
+static int f0(void);
+void g0(void) { __alignof__(f0()); }
+
+/* __typeof__ not variably modified, OK.  */
+static int f1(void);
+void g1(void) { __typeof__(f1()) x; }
+
+/* __typeof__ variably modified, not OK.  */
+static int f2(void); /* { dg-error "used but never defined" } */
+void g2(void) { __typeof__(int [f2()]) x; }
+
+/* __typeof__ variably modified, not OK.  */
+static int f3(void); /* { dg-error "used but never defined" } */
+void g3(void) { __typeof__(int (*)[f3()]) x; }
+
+/* Integer sizeof of VM typeof, OK.  */
+static int f4(void);
+void g4(void) { sizeof(__typeof__(int (*)[f3()])); }