Author: Aaron Ballman Date: 2022-11-29T14:44:37-05:00 New Revision: 2fc5a3410087c209567c7e4a2c457b6896c127a3
URL: https://github.com/llvm/llvm-project/commit/2fc5a3410087c209567c7e4a2c457b6896c127a3 DIFF: https://github.com/llvm/llvm-project/commit/2fc5a3410087c209567c7e4a2c457b6896c127a3.diff LOG: Add test coverage for more C DRs This completes the initial pass over all of the C DRs. Added: clang/test/C/drs/dr5xx.c Modified: clang/test/C/drs/dr4xx.c clang/www/c_dr_status.html Removed: ################################################################################ diff --git a/clang/test/C/drs/dr4xx.c b/clang/test/C/drs/dr4xx.c index 6acb47901bc4..768897cd4f2b 100644 --- a/clang/test/C/drs/dr4xx.c +++ b/clang/test/C/drs/dr4xx.c @@ -322,3 +322,63 @@ struct dr492_t { }; int m13; } dr492; + +/* WG14 DR496: yes + * offsetof questions + */ +void dr496(void) { + struct A { int n, a [2]; }; + struct B { struct A a; }; + struct C { struct A a[1]; }; + + /* The standard does not require either of these examples to work, but we + * support them just the same. The first one is invalid because it's + * referencing a member of a diff erent struct, and the second one is invalid + * because it references an array of another struct. Clang calculates the + * correct offset to each of those fields. + */ + _Static_assert(__builtin_offsetof(struct B, a.n) == 0, ""); + /* First int below is for 'n' and the second int is for 'a[0]'; this presumes + * there is no padding involved. + */ + _Static_assert(__builtin_offsetof(struct B, a.a[1]) == sizeof(int) + sizeof(int), ""); + + /* However, we do not support using the -> operator to access a member, even + * if that would be a valid expression. FIXME: GCC accepts this, perhaps we + * should as well. + */ + (void)__builtin_offsetof(struct C, a->n); /* expected-error {{expected ')'}} \ + expected-note {{to match this '('}} + */ + + /* The DR asked a question about whether defining a new type within offsetof + * is allowed. C2x N2350 made this explicitly undefined behavior, but Clang + * has always supported defining a type in this location, and GCC also + * supports it. + */ + (void)__builtin_offsetof(struct S { int a; }, a); +} + +/* WG14 DR499: yes + * Anonymous structure in union behavior + */ +void dr499(void) { + union U { + struct { + char B1; + char B2; + char B3; + char B4; + }; + int word; + } u; + + /* Validate that B1, B2, B3, and B4 do not have overlapping storage, only the + * anonymous structure and 'word' overlap. + */ + _Static_assert(__builtin_offsetof(union U, B1) == 0, ""); + _Static_assert(__builtin_offsetof(union U, B2) == 1, ""); + _Static_assert(__builtin_offsetof(union U, B3) == 2, ""); + _Static_assert(__builtin_offsetof(union U, B4) == 3, ""); + _Static_assert(__builtin_offsetof(union U, word) == 0, ""); +} diff --git a/clang/test/C/drs/dr5xx.c b/clang/test/C/drs/dr5xx.c new file mode 100644 index 000000000000..68bcef78bacc --- /dev/null +++ b/clang/test/C/drs/dr5xx.c @@ -0,0 +1,38 @@ +/* RUN: %clang_cc1 -std=c89 -verify=expected,c89only -pedantic -Wno-c11-extensions %s + RUN: %clang_cc1 -std=c99 -verify=expected -pedantic -Wno-c11-extensions %s + RUN: %clang_cc1 -std=c11 -verify=expected -pedantic %s + RUN: %clang_cc1 -std=c17 -verify=expected -pedantic %s + RUN: %clang_cc1 -std=c2x -verify=expected -pedantic %s + */ + +/* WG14 DR502: + * Flexible array member in an anonymous struct + */ +void dr502(void) { + /* This is EXAMPLE 3 from 6.7.2.1 and is intended to show that a flexible + * array member can be used when the only other members of the class are from + * an anonymous structure member. + */ + struct s { + struct { int i; }; + int a[]; /* c89only-warning {{flexible array members are a C99 feature}} */ + }; + + /* This is a slightly modified example that looks to see whether the + * anonymous structure itself can provide a flexible array member for the + * containing class. + * + * The committee does not think this is valid because it would mean the + * anonymous structure would have size 0. Additionally, the anonymous + * structure has no additional members and so the flexible array member is + * not valid within the anonymous structure. + */ + struct t { + int i; + struct { int a[]; }; /* expected-error {{flexible array member 'a' not allowed in otherwise empty struct}} + c89only-warning {{flexible array members are a C99 feature}} + expected-warning {{'' may not be nested in a struct due to flexible array member}} + */ + }; +} + diff --git a/clang/www/c_dr_status.html b/clang/www/c_dr_status.html index 47a7a036a506..ea3859771736 100644 --- a/clang/www/c_dr_status.html +++ b/clang/www/c_dr_status.html @@ -2632,7 +2632,7 @@ <h2 id="cdr">C defect report implementation status</h2> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2148.htm#dr_496";>496</a></td> <td>NAD</td> <td>offsetof questions</td> - <td class="unknown" align="center">Unknown</td> + <td class="full" align="center">Yes</td> </tr> <tr id="497"> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2148.htm#dr_497";>497</a></td> @@ -2650,7 +2650,7 @@ <h2 id="cdr">C defect report implementation status</h2> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2396.htm#dr_499";>499</a></td> <td>C17</td> <td>Anonymous structure in union behavior</td> - <td class="unknown" align="center">Unknown</td> + <td class="full" align="center">Yes</td> </tr> <tr id="500"> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2396.htm#dr_500";>500</a></td> @@ -2668,13 +2668,13 @@ <h2 id="cdr">C defect report implementation status</h2> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2396.htm#dr_502";>502</a></td> <td>NAD</td> <td>Flexible array member in an anonymous struct</td> - <td class="unknown" align="center">Unknown</td> + <td class="full" align="center">Yes</td> </tr> <tr id="503"> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2396.htm#dr_503";>503</a></td> <td>NAD</td> <td>Hexadecimal floating-point and strtod</td> - <td class="unknown" align="center">Unknown</td> + <td class="na" align="center">N/A</td> </tr> _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
