| Summary: | gcc/c-family/c-attribs.c:1822:27: runtime error: shift exponent -1 is negative | ||
|---|---|---|---|
| Product: | gcc | Reporter: | Martin Liška <marxin> |
| Component: | c++ | Assignee: | Marek Polacek <mpolacek> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | jason, nathan |
| Priority: | P3 | ||
| Version: | 8.0.1 | ||
| Target Milestone: | --- | ||
| Host: | Target: | x86_64-*-*, i?86-*-* | |
| Build: | Known to work: | ||
| Known to fail: | Last reconfirmed: | 2018-03-01 00:00:00 | |
| Bug Depends on: | |||
| Bug Blocks: | 63426 | ||
Confirmed with an assert. Can be fixed by moving the checking a bit above:
--- a/gcc/c-family/c-attribs.c
+++ b/gcc/c-family/c-attribs.c
@@ -1818,6 +1818,13 @@ common_handle_aligned_attribute (tree *node, tree name, tree args, int flags,
/* Log2 of specified alignment. */
int pow2align = check_user_alignment (align_expr, true);
+ if (pow2align == -1
+ || !check_cxx_fundamental_alignment_constraints (*node, pow2align, flags))
+ {
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+
/* The alignment in bits corresponding to the specified alignment. */
unsigned bitalign = (1U << pow2align) * BITS_PER_UNIT;
@@ -1826,10 +1833,7 @@ common_handle_aligned_attribute (tree *node, tree name, tree args, int flags,
unsigned curalign = 0;
unsigned lastalign = 0;
- if (pow2align == -1
- || !check_cxx_fundamental_alignment_constraints (*node, pow2align, flags))
- *no_add_attrs = true;
- else if (is_type)
+ if (is_type)
{
if ((flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
/* OK, modify the type in place. */;
Author: mpolacek Date: Thu Mar 1 19:15:42 2018 New Revision: 258109 URL: https://gcc.gnu.org/viewcvs?rev=258109&root=gcc&view=rev Log: PR c++/84639 * c-attribs.c (common_handle_aligned_attribute): Don't use invalid alignment in computation. Modified: trunk/gcc/c-family/ChangeLog trunk/gcc/c-family/c-attribs.c Fixed in GCC 8. |
UBSAN gcc prints the error: $ UBSAN_OPTIONS="print_stacktrace=1" ./xg++ -B. /home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp0x/alignas12.C /home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp0x/alignas12.C:6:10: error: ‘alignas’ argument has non-integral type ‘<unresolved overloaded function type>’ alignas (f < int >) char c; // { dg-error "non-integral type" } ^~~~~~~~~ ../../gcc/c-family/c-attribs.c:1822:27: runtime error: shift exponent -1 is negative #0 0x5e311c in common_handle_aligned_attribute ../../gcc/c-family/c-attribs.c:1822 #1 0xe29d06 in decl_attributes(tree_node**, tree_node*, int, tree_node*) ../../gcc/attribs.c:685 #2 0x991bd9 in cplus_decl_attributes(tree_node**, tree_node*, int) ../../gcc/cp/decl2.c:1546 #3 0x95790d in start_decl(cp_declarator const*, cp_decl_specifier_seq*, int, tree_node*, tree_node*, tree_node**) ../../gcc/cp/decl.c:5047 #4 0xb95381 in cp_parser_init_declarator ../../gcc/cp/parser.c:19587 #5 0xbaef4d in cp_parser_simple_declaration ../../gcc/cp/parser.c:13053 #6 0xbb230e in cp_parser_block_declaration ../../gcc/cp/parser.c:12878 #7 0xbc4460 in cp_parser_declaration ../../gcc/cp/parser.c:12776 #8 0xbc66a1 in cp_parser_declaration_seq_opt ../../gcc/cp/parser.c:12652 #9 0xbc7628 in cp_parser_translation_unit ../../gcc/cp/parser.c:4559 #10 0xbc7628 in c_parse_file() ../../gcc/cp/parser.c:38880 #11 0xeec35c in c_common_parse_file() ../../gcc/c-family/c-opts.c:1132 #12 0x25a2cdc in compile_file ../../gcc/toplev.c:455 #13 0x77e2e9 in do_compile ../../gcc/toplev.c:2132 #14 0x77e2e9 in toplev::main(int, char**) ../../gcc/toplev.c:2267 #15 0x78117a in main ../../gcc/main.c:39 #16 0x7fd52c3026e4 in __libc_start_main (/lib64/libc.so.6+0x206e4) #17 0x7812a8 in _start (/home/marxin/Programming/gcc/objdir/gcc/cc1plus+0x7812a8)