GCC 10 has changed the formatting of zero-length arrays in diagnostics
to include their bound, but it also inadvertently added the zero bound
to flexible array members which are confusingly represented differently
between the C and C++ front ends.
The attached patch corrects the problem so both zero-length arrays and
flexible array members are formatted consistently by both front ends
(i.e., as T[0] and T[]).
Tested on x86_64-linux.
Martin
PR c/92326 - wrong bound in zero-length array diagnostics
gcc/c-family/ChangeLog:
PR c/92326
* c-pretty-print.c (c_pretty_printer::direct_abstract_declarator): Avoid
printing array bound for flexible array members.
gcc/testsuite/ChangeLog:
PR c/92326
* c-c++-common/Warray-bounds-8.c: New test.
* gcc.dg/Warray-bounds-46.c: Adjust expected format of flexible array
memebrs in diagnostics.
* gcc.dg/Warray-bounds-49.c: Same.
diff --git a/gcc/c-family/c-pretty-print.c b/gcc/c-family/c-pretty-print.c
index 0e4303f1a49..eccb63096fd 100644
--- a/gcc/c-family/c-pretty-print.c
+++ b/gcc/c-family/c-pretty-print.c
@@ -593,7 +593,9 @@ c_pretty_printer::direct_abstract_declarator (tree t)
expression (fold_build2 (PLUS_EXPR, type, maxval,
build_int_cst (type, 1)));
}
- else
+ else if (TYPE_SIZE (t))
+ /* Print zero for zero-length arrays but not for flexible
+ array members whose TYPE_SIZE is null. */
pp_string (this, "0");
}
pp_c_right_bracket (this);
diff --git a/gcc/testsuite/c-c++-common/Warray-bounds-8.c b/gcc/testsuite/c-c++-common/Warray-bounds-8.c
new file mode 100644
index 00000000000..64202ddd5df
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Warray-bounds-8.c
@@ -0,0 +1,22 @@
+/* PR c/92326 - wrong bound in zero-length array diagnostics
+ { dg-do compile }
+ { dg-options "-O2 -Wall" } */
+
+extern int a0[0];
+extern int ax[];
+
+void warn_global_array (void)
+{
+ a0[0] = 0; // { dg-warning "array bounds of 'int *\\\[0]'" }
+ ax[-1] = 0; // { dg-warning "array bounds of 'int *\\\[]'" }
+}
+
+
+struct S0 { int n, a0[0]; } s0;
+struct Sx { int n, ax[]; } sx = { 0 };
+
+void warn_member_array (void)
+{
+ s0.a0[0] = 0; // { dg-warning "array bounds of 'int *\\\[0]'" }
+ sx.ax[0] = 0; // { dg-warning "array bounds of 'int *\\\[]'" }
+}
diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-46.c b/gcc/testsuite/gcc.dg/Warray-bounds-46.c
index 74e78cbdbe8..9078c6f5998 100644
--- a/gcc/testsuite/gcc.dg/Warray-bounds-46.c
+++ b/gcc/testsuite/gcc.dg/Warray-bounds-46.c
@@ -95,13 +95,13 @@ void strcpy_global_array (void)
/* GMA2 is external but because it's an array its definition in another
translation unit may not provide an initializer for the flexible array
member. Verify that a warning is issued for access to it. */
- T (gma2[0].ax, 1); // { dg-warning "'strcpy' offset \\\[157, 158] from the object at 'gma2' is out of the bounds of referenced subobject 'ax' with type 'char\\\[0]' at offset 157" }
- T (gma2[0].ax, 7); // { dg-warning "'strcpy' offset \\\[157, 164] from the object at 'gma2' is out of the bounds of referenced subobject 'ax' with type 'char\\\[0]' at offset 157" }
+ T (gma2[0].ax, 1); // { dg-warning "'strcpy' offset \\\[157, 158] from the object at 'gma2' is out of the bounds of referenced subobject 'ax' with type 'char\\\[]' at offset 157" }
+ T (gma2[0].ax, 7); // { dg-warning "'strcpy' offset \\\[157, 164] from the object at 'gma2' is out of the bounds of referenced subobject 'ax' with type 'char\\\[]' at offset 157" }
- /* IGMA_ is internal and provides on definition for the flexible array
- member. Verify that a warnin is issued for out-of-bounds accesses
+ /* IGMA2_ is internal and provides no definition for the flexible array
+ member. Verify that a warning is issued for out-of-bounds accesses
to it. */
- T (igma2_[0].ax, 1); // { dg-warning "'strcpy' offset \\\[157, 158] from the object at 'igma2_' is out of the bounds of referenced subobject 'ax' with type 'char\\\[0]' at offset 157" }
+ T (igma2_[0].ax, 1); // { dg-warning "'strcpy' offset \\\[157, 158] from the object at 'igma2_' is out of the bounds of referenced subobject 'ax' with type 'char\\\[]' at offset 157" }
T (igma_3.ax, 0);
T (igma_3.ax, 1);
@@ -134,7 +134,7 @@ void strcpy_local (void)
T (lma.a17, 16);
T (lma.a17, 17); // { dg-warning "'strcpy' offset 157 from the object at 'lma' is out of the bounds of referenced subobject 'a17' with type 'char\\\[17]' at offset 140" }
- T (lma.ax, 0); // { dg-warning "'strcpy' offset 157 from the object at 'lma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[0]' at offset 157" }
+ T (lma.ax, 0); // { dg-warning "'strcpy' offset 157 from the object at 'lma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[]' at offset 157" }
}
@@ -191,11 +191,11 @@ void strcpy_ref (struct MA17 *pma)
array. The warning assumes that PMA doesn't point to the last element
of the array which could in theory have nonzero elements without
overlapping other objects. */
- T (pma[1].ax, 0); // { dg-warning "'strcpy' offset 314 from the object at 'pma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[0]' at offset 314" }
- T ((pma + 1)->ax, 1); // { dg-warning "'strcpy' offset \\\[314, 315] from the object at 'pma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[0]' at offset 314" }
- T ((pma + 1)[1].ax, 2); // { dg-warning "'strcpy' offset \\\[471, 473] from the object at 'pma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[0]' at offset 471" }
- T ((*(pma + 2)).ax, 2); // { dg-warning "'strcpy' offset \\\[471, 473] from the object at 'pma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[0]' at offset 471" }
- T (pma[3].ax, 9); // { dg-warning "'strcpy' offset \\\[628, 637] from the object at 'pma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[0]' at offset 628" }
+ T (pma[1].ax, 0); // { dg-warning "'strcpy' offset 314 from the object at 'pma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[]' at offset 314" }
+ T ((pma + 1)->ax, 1); // { dg-warning "'strcpy' offset \\\[314, 315] from the object at 'pma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[]' at offset 314" }
+ T ((pma + 1)[1].ax, 2); // { dg-warning "'strcpy' offset \\\[471, 473] from the object at 'pma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[]' at offset 471" }
+ T ((*(pma + 2)).ax, 2); // { dg-warning "'strcpy' offset \\\[471, 473] from the object at 'pma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[]' at offset 471" }
+ T (pma[3].ax, 9); // { dg-warning "'strcpy' offset \\\[628, 637] from the object at 'pma' is out of the bounds of referenced subobject 'ax' with type 'char\\\[]' at offset 628" }
T (pma[-1].a1, 0);
T (pma[-1].a1, 1); // { dg-warning "'strcpy' offset -152 from the object at 'pma' is out of the bounds of referenced subobject 'a1' with type 'char\\\[1]' at offset -153" }
diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-49.c b/gcc/testsuite/gcc.dg/Warray-bounds-49.c
index 7a847acf4d2..f271dd526b8 100644
--- a/gcc/testsuite/gcc.dg/Warray-bounds-49.c
+++ b/gcc/testsuite/gcc.dg/Warray-bounds-49.c
@@ -17,7 +17,7 @@ void test_a0 (void)
// The first three elements fit in the tail padding.
a0.a2[0] = 0; a0.a2[1] = 1; a0.a2[2] = 2;
- a0.a2[3] = 3; // { dg-warning "array subscript 3 is above array bounds of 'short int\\\[0]'" }
+ a0.a2[3] = 3; // { dg-warning "array subscript 3 is above array bounds of 'short int\\\[]'" }
}
@@ -27,7 +27,7 @@ void test_a1 (void)
{
a1.a2[0] = 0; a1.a2[1] = 1; a1.a2[2] = 2;
- a1.a2[3] = 3; // { dg-warning "array subscript 3 is above array bounds of 'short int\\\[0]'" }
+ a1.a2[3] = 3; // { dg-warning "array subscript 3 is above array bounds of 'short int\\\[]'" }
}
@@ -37,7 +37,7 @@ void test_a2 (void)
{
a2.a2[0] = 0; a2.a2[1] = 1; a2.a2[2] = 2;
- a2.a2[3] = 3; // { dg-warning "array subscript 3 is above array bounds of 'short int\\\[0]'" }
+ a2.a2[3] = 3; // { dg-warning "array subscript 3 is above array bounds of 'short int\\\[]'" }
}
@@ -47,7 +47,7 @@ void test_a3 (void)
{
a3.a2[0] = 0; a3.a2[1] = 1; a3.a2[2] = 2;
- a3.a2[3] = 3; // { dg-warning "array subscript 3 is above array bounds of 'short int\\\[0]'" }
+ a3.a2[3] = 3; // { dg-warning "array subscript 3 is above array bounds of 'short int\\\[]'" }
}
@@ -57,7 +57,7 @@ void test_a4 (void)
{
a4.a2[0] = 0; a4.a2[1] = 1; a4.a2[2] = 2; a4.a2[3] = 3;
- a4.a2[4] = 4; // { dg-warning "array subscript 4 is above array bounds of 'short int\\\[0]'" }
+ a4.a2[4] = 4; // { dg-warning "array subscript 4 is above array bounds of 'short int\\\[]'" }
}
@@ -67,7 +67,7 @@ void test_a5 (void)
{
a5.a2[0] = 0; a5.a2[1] = 1; a5.a2[2] = 2; a5.a2[3] = 3; a5.a2[4] = 4;
- a5.a2[5] = 5; // { dg-warning "array subscript 5 is above array bounds of 'short int\\\[0]'" }
+ a5.a2[5] = 5; // { dg-warning "array subscript 5 is above array bounds of 'short int\\\[]'" }
}
@@ -78,7 +78,7 @@ void test_a6 (void)
a6.a2[0] = 0; a6.a2[1] = 1; a6.a2[2] = 2; a6.a2[3] = 3; a6.a2[4] = 4;
a6.a2[5] = 5;
- a6.a2[6] = 6; // { dg-warning "array subscript 6 is above array bounds of 'short int\\\[0]'" }
+ a6.a2[6] = 6; // { dg-warning "array subscript 6 is above array bounds of 'short int\\\[]'" }
}
@@ -89,7 +89,7 @@ void test_a7 (void)
a7.a2[0] = 0; a7.a2[1] = 1; a7.a2[2] = 2; a7.a2[3] = 3; a7.a2[4] = 4;
a7.a2[5] = 5; a7.a2[5] = 5; a7.a2[6] = 6;
- a7.a2[7] = 7; // { dg-warning "array subscript 7 is above array bounds of 'short int\\\[0]'" }
+ a7.a2[7] = 7; // { dg-warning "array subscript 7 is above array bounds of 'short int\\\[]'" }
}
@@ -100,7 +100,7 @@ void test_a8 (void)
a8.a2[0] = 0; a8.a2[1] = 1; a8.a2[2] = 2; a8.a2[3] = 3; a8.a2[4] = 4;
a8.a2[5] = 5; a8.a2[5] = 5; a8.a2[6] = 6; a8.a2[7] = 7;
- a8.a2[8] = 8; // { dg-warning "array subscript 8 is above array bounds of 'short int\\\[0]'" }
+ a8.a2[8] = 8; // { dg-warning "array subscript 8 is above array bounds of 'short int\\\[]'" }
}
@@ -111,5 +111,5 @@ void test_a9 (void)
a8.a2[0] = 8; a8.a2[1] = 7; a8.a2[2] = 6; a8.a2[3] = 5; a8.a2[4] = 4;
a8.a2[5] = 3; a8.a2[5] = 2; a8.a2[6] = 1; a8.a2[7] = 0;
- a8.a2[9] = 8; // { dg-warning "array subscript 9 is above array bounds of 'short int\\\[0]'" }
+ a8.a2[9] = 8; // { dg-warning "array subscript 9 is above array bounds of 'short int\\\[]'" }
}
