re PR c/67882 (surprising offsetof result on an invalid array member without diagnostic)
PR c++-common/67882
* c-family/c-common.h (fold_offsetof_1): Add argument.
* c-family/c-common.c (fold_offsetof_1): Diagnose more invalid
offsetof expressions that reference elements past the end of
an array.
* c-c++-common/builtin-offsetof-2.c: New test.
From-SVN: r229717
This commit is contained in:
Martin Sebor
parent
aa3d33850f
commit
c85158dec6
5 changed files with 239 additions and 8 deletions
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@ -1,3 +1,11 @@
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2015-11-03 Bernd Schmidt <bschmidt@redhat.com>
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PR c++-common/67882
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* c-family/c-common.h (fold_offsetof_1): Add argument.
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* c-family/c-common.c (fold_offsetof_1): Diagnose more invalid
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offsetof expressions that reference elements past the end of
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an array.
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2015-11-03 Thomas Schwinge <thomas@codesourcery.com>
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Chung-Lin Tang <cltang@codesourcery.com>
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@ -10631,11 +10631,11 @@ c_common_to_target_charset (HOST_WIDE_INT c)
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traditional rendering of offsetof as a macro. Return the folded result. */
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tree
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fold_offsetof_1 (tree expr)
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fold_offsetof_1 (tree expr, enum tree_code ctx)
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{
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tree base, off, t;
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switch (TREE_CODE (expr))
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tree_code code = TREE_CODE (expr);
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switch (code)
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{
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case ERROR_MARK:
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return expr;
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@ -10659,7 +10659,7 @@ fold_offsetof_1 (tree expr)
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return TREE_OPERAND (expr, 0);
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case COMPONENT_REF:
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base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
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base = fold_offsetof_1 (TREE_OPERAND (expr, 0), code);
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if (base == error_mark_node)
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return base;
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@ -10676,7 +10676,7 @@ fold_offsetof_1 (tree expr)
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break;
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case ARRAY_REF:
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base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
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base = fold_offsetof_1 (TREE_OPERAND (expr, 0), code);
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if (base == error_mark_node)
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return base;
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@ -10691,8 +10691,9 @@ fold_offsetof_1 (tree expr)
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&& !tree_int_cst_equal (upbound,
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TYPE_MAX_VALUE (TREE_TYPE (upbound))))
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{
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upbound = size_binop (PLUS_EXPR, upbound,
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build_int_cst (TREE_TYPE (upbound), 1));
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if (ctx != ARRAY_REF && ctx != COMPONENT_REF)
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upbound = size_binop (PLUS_EXPR, upbound,
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build_int_cst (TREE_TYPE (upbound), 1));
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if (tree_int_cst_lt (upbound, t))
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{
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tree v;
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@ -1029,7 +1029,7 @@ extern bool c_dump_tree (void *, tree);
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extern void verify_sequence_points (tree);
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extern tree fold_offsetof_1 (tree);
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extern tree fold_offsetof_1 (tree, tree_code ctx = ERROR_MARK);
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extern tree fold_offsetof (tree);
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/* Places where an lvalue, or modifiable lvalue, may be required.
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@ -1,3 +1,8 @@
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2015-11-03 Martin Sebor <msebor@redhat.com>
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PR c++-common/67882
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* c-c++-common/builtin-offsetof-2.c: New test.
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2015-11-03 Dominique d'Humieres <dominiq@lps.ens.fr>
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PR fortran/67982
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217
gcc/testsuite/c-c++-common/builtin-offsetof-2.c
Normal file
217
gcc/testsuite/c-c++-common/builtin-offsetof-2.c
Normal file
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@ -0,0 +1,217 @@
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// { dg-options "-Warray-bounds" }
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// { dg-do compile }
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// Test case exercising pr c/67882 - surprising offsetof result
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// on an invalid array member without diagnostic.
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typedef struct A1 {
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char a1[1];
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char c;
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} A1;
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typedef struct A1_x_2 {
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char a1[1];
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char a[][2];
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} A1_x_2;
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typedef struct A1_1_x {
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char a1_1[1][1];
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char a[];
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} A1_1_x;
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typedef struct Ax_2_3 {
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int i;
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char a_x_2_3[][2][3];
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} Ax_2_3;
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typedef struct A1_1 {
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char a1_1[1][1];
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char c;
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} A1_1;
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typedef struct B {
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A1_1 a2_3[2][3];
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char a1_1[3][5];
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char a[];
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} B;
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// Structures with members that contain flexible array members are
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// an extension accepted by GCC.
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typedef struct C {
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A1_1_x a5_7 [5][7];
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int a;
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} C;
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// Structs with a "fake" flexible array member (a GCC extension).
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typedef struct FA0 {
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int i;
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char a0 [0];
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} FA0;
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typedef struct FA1 {
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int i;
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char a1 [1];
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} FA1;
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typedef struct FA3 {
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int i;
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char a3 [3];
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} FA3;
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// A "fake" multidimensional flexible array member.
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typedef struct FA5_7 {
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int i;
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char a5_7 [5][7];
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} FA5_7;
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static void test (void)
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{
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// Verify that offsetof references to array elements past the end of
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// the array member are diagnosed. As an extension, permit references
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// to the element just past-the-end of the array.
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int a[] = {
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__builtin_offsetof (A1, a1), // valid
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__builtin_offsetof (A1, a1 [0]), // valid
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// The following expression is valid because it forms the equivalent
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// of an address pointing just past the last element of the array.
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__builtin_offsetof (A1, a1 [1]), // valid
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__builtin_offsetof (A1, a1 [2]), // { dg-warning "index" }
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__builtin_offsetof (A1_x_2, a1), // valid
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__builtin_offsetof (A1_x_2, a1 [0]), // valid
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__builtin_offsetof (A1_x_2, a1 [1]), // valid
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__builtin_offsetof (A1_x_2, a1 [2]), // { dg-warning "index" }
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__builtin_offsetof (A1_x_2, a), // valid
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__builtin_offsetof (A1_x_2, a [0]), // valid
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__builtin_offsetof (A1_x_2, a [1]), // valid
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__builtin_offsetof (A1_x_2, a [99]), // valid
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__builtin_offsetof (A1_x_2, a), // valid
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__builtin_offsetof (A1_x_2, a [0][0]), // valid
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__builtin_offsetof (A1_x_2, a [0][1]), // valid
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// The following expression is valid because it forms the equivalent
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// of an address pointing just past the last element of the first
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// array.
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__builtin_offsetof (A1_x_2, a [0][2]), // valid
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// Unlike the case above, this is invalid since it refers to an element
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// past one one just-past-the-end in A[][2].
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__builtin_offsetof (A1_x_2, a [0][3]), // { dg-warning "index" }
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__builtin_offsetof (A1_x_2, a [1][0]), // valid
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__builtin_offsetof (A1_x_2, a [1][1]), // valid
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__builtin_offsetof (A1_x_2, a [1][2]), // valid
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__builtin_offsetof (A1_x_2, a [99][0]), // valid
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__builtin_offsetof (A1_x_2, a [99][1]), // valid
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__builtin_offsetof (A1_x_2, a [99][2]), // valid
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__builtin_offsetof (A1_1_x, a), // valid
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__builtin_offsetof (A1_1_x, a [0]), // valid
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__builtin_offsetof (A1_1_x, a [1]), // valid
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__builtin_offsetof (A1_1_x, a [99]), // valid
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__builtin_offsetof (A1_1_x, a1_1 [0][0]), // valid
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__builtin_offsetof (A1_1_x, a1_1 [0][1]), // valid
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__builtin_offsetof (A1_1_x, a1_1 [0][2]), // { dg-warning "index" }
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__builtin_offsetof (A1_1_x, a1_1 [1][0]), // { dg-warning "index" }
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__builtin_offsetof (A1_1_x, a1_1 [1][1]), // { dg-warning "index" }
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__builtin_offsetof (Ax_2_3, a_x_2_3 [0][1][3]), // valid
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__builtin_offsetof (Ax_2_3, a_x_2_3 [0][1][4]), // { dg-warning "index" }
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__builtin_offsetof (Ax_2_3, a_x_2_3 [0][2]), // valid
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__builtin_offsetof (Ax_2_3, a_x_2_3 [0][2][0]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [0][0].c), // valid
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__builtin_offsetof (B, a2_3 [0][0].a1_1 [0][0]), // valid
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__builtin_offsetof (B, a2_3 [1][3]), // valid
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__builtin_offsetof (B, a2_3 [1][4]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [0][0].a1_1 [0][1]), // valid
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__builtin_offsetof (B, a2_3 [0][0].a1_1 [0][2]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [0][0].a1_1 [1][0]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [0][0].a1_1 [1][1]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [1][2].a1_1 [0][0]), // valid
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// Forming an offset to the just-past-end element is valid.
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__builtin_offsetof (B, a2_3 [1][2].a1_1 [0][1]), // valid
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__builtin_offsetof (B, a2_3 [1][2].a1_1 [1][0]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [1][2].a1_1 [1][1]), // { dg-warning "index" }
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// Forming an offset to the just-past-end element is valid.
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__builtin_offsetof (B, a2_3 [1][3]), // valid
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// ...but these are diagnosed because they dereference a just-past-the-end
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// element.
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__builtin_offsetof (B, a2_3 [1][3].a1_1 [0][0]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [1][3].a1_1 [0][0]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [1][3].a1_1 [0][1]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [1][3].a1_1 [1][0]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [1][3].a1_1 [1][1]), // { dg-warning "index" }
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// Analogous to the case above, these are both diagnosed because they
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// dereference just-past-the-end elements of the a2_3 array.
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__builtin_offsetof (B, a2_3 [1][3].c), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [1][3].c), // { dg-warning "index" }
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// The following are all invalid because of the reference to a2_3[2].
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__builtin_offsetof (B, a2_3 [2][0].a1_1 [0][0]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [2][0].a1_1 [0][1]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [2][0].a1_1 [1][0]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [2][0].a1_1 [1][1]), // { dg-warning "index" }
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__builtin_offsetof (B, a2_3 [2][0].c), // { dg-warning "index" }
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__builtin_offsetof (C, a5_7 [4][6]),
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__builtin_offsetof (C, a5_7 [4][6].a),
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__builtin_offsetof (C, a5_7 [4][6].a [0]),
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__builtin_offsetof (C, a5_7 [4][6].a [99]),
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__builtin_offsetof (C, a5_7 [4][7]), // valid
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// Diagnose the following even though the object whose offset is
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// computed is a flexible array member.
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__builtin_offsetof (C, a5_7 [4][7].a), // { dg-warning "index" }
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__builtin_offsetof (C, a5_7 [4][7].a [0]), // { dg-warning "index" }
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__builtin_offsetof (C, a5_7 [4][7].a [99]), // { dg-warning "index" }
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// Verify that no diagnostic is issued for offsetof expressions
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// involving structs where the array has a rank of 1 and is the last
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// member (e.g., those are treated as flexible array members).
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__builtin_offsetof (FA0, a0 [0]),
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__builtin_offsetof (FA0, a0 [1]),
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__builtin_offsetof (FA0, a0 [99]),
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__builtin_offsetof (FA1, a1 [0]),
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__builtin_offsetof (FA1, a1 [1]),
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__builtin_offsetof (FA1, a1 [99]),
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__builtin_offsetof (FA3, a3 [0]),
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__builtin_offsetof (FA3, a3 [3]),
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__builtin_offsetof (FA3, a3 [99]),
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__builtin_offsetof (FA5_7, a5_7 [0][0]),
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// Unlike one-dimensional arrays, verify that out-of-bounds references
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// to "fake" flexible arrays with rank of 2 and greater are diagnosed.
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// The following are valid because they compute the offset of just past
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// the end of each of the a5_7[0] and a5_7[1] arrays.
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__builtin_offsetof (FA5_7, a5_7 [0][7]), // valid
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__builtin_offsetof (FA5_7, a5_7 [1][7]), // valid
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// The following two are accepted as an extesion (because a5_7 is
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// treated as a flexible array member).
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__builtin_offsetof (FA5_7, a5_7 [5][0]), // extension
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__builtin_offsetof (FA5_7, a5_7 [5][7]), // extension
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// The following are invalid since in both cases they denote an element
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// that's beyond just-past-the-end of the array.
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__builtin_offsetof (FA5_7, a5_7 [0][8]), // { dg-warning "index" }
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__builtin_offsetof (FA5_7, a5_7 [6][8]) // { dg-warning "index" }
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};
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(void)&a;
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}
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