avoid treating more incompatible redeclarations as builtin-ins [PR94040]

Message ID	96819cd6-2bef-a056-6476-a55c6e72fe30@gmail.com
State	New
Headers	show Return-Path: <gcc-patches-return-520744-incoming=patchwork.ozlabs.org@gcc.gnu.org> DomainKey-Signature: a=rsa-sha1; c=nofws; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:to :from:subject:message-id:date:mime-version:content-type; q=dns; s=default; b=VxsK3M7uRf64CmPq/WPAttzrq1nxBSNZ5vBpfxUt/xSxVTMlTu pZiHBXEXo2jvqVgBkhI8Ns1hqsafuE3jsE7HVgx6Ez826mZ070lu6IWLSIMowRIC PXXFFj9EVsKEkFAIvDhJ+Nv9fn4n1XRrCX03iadHUp/afAzV2NNw3glPM= Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk Sender: gcc-patches-owner@gcc.gnu.org To: gcc-patches <gcc-patches@gcc.gnu.org> From: Martin Sebor <msebor@gmail.com> Subject: [PATCH] avoid treating more incompatible redeclarations as builtin-ins [PR94040] Message-ID: <96819cd6-2bef-a056-6476-a55c6e72fe30@gmail.com> Date: Thu, 5 Mar 2020 18:04:37 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="------------E8CDB15114AAA2702EB6D7BD"
Series	avoid treating more incompatible redeclarations as builtin-ins [PR94040] \| expand avoid treating more incompatible redeclarations as builtin-ins [PR94040]

PR c/94040 - ICE on a call to an invalid redeclaration of strftime gcc/c/ChangeLog: PR c/94040 * c-decl.c (builtin_structptr_type_count): New constant. (match_builtin_function_types): Reject decls that are incompatible in types pointed to by pointers. (diagnose_mismatched_decls): Adjust comments. gcc/testsuite/ChangeLog: PR c/94040 * gcc.dg/Wbuiltin-declaration-mismatch-12.c: Relax test to look for warning name rather than the exact text. * gcc.dg/Wbuiltin-declaration-mismatch-14.c: New test. * gcc.dg/Wbuiltin-declaration-mismatch-15.c: New test. * gcc.dg/pr62090.c: Prune expected warning. * gcc.dg/pr89314.c: Look for warning name rather than text. diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c index c819fd0d0d5..87a0734b715 100644 --- a/gcc/c/c-decl.c +++ b/gcc/c/c-decl.c @@ -1641,13 +1641,17 @@ c_bind (location_t loc, tree decl, bool is_global) } -/* Stores the first FILE*, const struct tm* etc. argument type (whatever it - is) seen in a declaration of a file I/O etc. built-in. Subsequent - declarations of such built-ins are expected to refer to it rather than to - fileptr_type_node etc. which is just void* (or to any other type). +/* Stores the first FILE*, const struct tm* etc. argument type (whatever + it is) seen in a declaration of a file I/O etc. built-in, corresponding + to the builtin_structptr_types array. Subsequent declarations of such + built-ins are expected to refer to it rather than to fileptr_type_node, + etc. which is just void* (or to any other type). Used only by match_builtin_function_types. */ -static GTY(()) tree last_structptr_types[6]; +static const unsigned builtin_structptr_type_count + = sizeof builtin_structptr_types / sizeof builtin_structptr_types[0]; + +static GTY(()) tree last_structptr_types[builtin_structptr_type_count]; /* Returns true if types T1 and T2 representing return types or types of function arguments are close enough to be considered interchangeable @@ -1692,10 +1696,13 @@ match_builtin_function_types (tree newtype, tree oldtype, tree newargs = TYPE_ARG_TYPES (newtype); tree tryargs = newargs; - gcc_checking_assert ((sizeof (last_structptr_types) - / sizeof (last_structptr_types[0])) - == (sizeof (builtin_structptr_types) - / sizeof (builtin_structptr_types[0]))); + const unsigned nlst + = sizeof last_structptr_types / sizeof last_structptr_types[0]; + const unsigned nbst + = sizeof builtin_structptr_types / sizeof builtin_structptr_types[0]; + + gcc_checking_assert (nlst == nbst); + for (unsigned i = 1; oldargs || newargs; ++i) { if (!oldargs @@ -1710,11 +1717,12 @@ match_builtin_function_types (tree newtype, tree oldtype, if (!types_close_enough_to_match (oldtype, newtype)) return NULL_TREE; - unsigned j = (sizeof (builtin_structptr_types) - / sizeof (builtin_structptr_types[0])); + unsigned j = nbst; if (POINTER_TYPE_P (oldtype)) - for (j = 0; j < (sizeof (builtin_structptr_types) - / sizeof (builtin_structptr_types[0])); ++j) + /* Iterate over well-known struct types like FILE (whose types + aren't known to us) and compare the pointer to each to + the pointer argument. */ + for (j = 0; j < nbst; ++j) { if (TREE_VALUE (oldargs) != builtin_structptr_types[j].node) continue; @@ -1734,13 +1742,26 @@ match_builtin_function_types (tree newtype, tree oldtype, last_structptr_types[j] = newtype; break; } - if (j == (sizeof (builtin_structptr_types) - / sizeof (builtin_structptr_types[0])) - && !*strict - && !comptypes (oldtype, newtype)) + + if (j == nbst && !comptypes (oldtype, newtype)) { - *argno = i; - *strict = oldtype; + if (POINTER_TYPE_P (oldtype)) + { + /* For incompatible pointers, only reject differences in + the unqualified variants of the referenced types but + consider differences in qualifiers as benign (report + those to caller via *STRICT below). */ + tree oldref = TYPE_MAIN_VARIANT (TREE_TYPE (oldtype)); + tree newref = TYPE_MAIN_VARIANT (TREE_TYPE (newtype)); + if (!comptypes (oldref, newref)) + return NULL_TREE; + } + + if (!*strict) + { + *argno = i; + *strict = oldtype; + } } oldargs = TREE_CHAIN (oldargs); @@ -1965,9 +1986,8 @@ diagnose_mismatched_decls (tree newdecl, tree olddecl, { /* Accept "harmless" mismatches in function types such as missing qualifiers or int vs long when they're the same - size. However, with -Wextra in effect, diagnose return and - argument types that are incompatible according to language - rules. */ + size. However, diagnose return and argument types that are + incompatible according to language rules. */ tree mismatch_expect; unsigned mismatch_argno; @@ -2002,8 +2022,6 @@ diagnose_mismatched_decls (tree newdecl, tree olddecl, if (mismatch_expect && extra_warnings) { - /* If types match only loosely, print a warning but accept - the redeclaration. */ location_t newloc = DECL_SOURCE_LOCATION (newdecl); bool warned = false; if (mismatch_argno) diff --git a/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-12.c b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-12.c index 6bf97623b8d..f12ef6afb10 100644 --- a/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-12.c +++ b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-12.c @@ -3,6 +3,6 @@ { dg-do compile } { dg-options "-Wbuiltin-declaration-mismatch -Wextra" } */ -extern void __clear_cache (char*, char*); /* { dg-warning "mismatch in argument 1 type of built-in function .__clear_cache.; expected .void \\\*." } */ +extern void __clear_cache (char*, char*); // { dg-warning "\\\[-Wbuiltin-declaration-mismatch" } -void __builtin_prefetch (const char *, ...); /* { dg-warning "mismatch in argument 1 type of built-in function .__builtin_prefetch.; expected .const void \\\*." } */ +void __builtin_prefetch (const char *, ...); // { dg-warning "\\\[-Wbuiltin-declaration-mismatch" } diff --git a/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-14.c b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-14.c new file mode 100644 index 00000000000..cc536d71431 --- /dev/null +++ b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-14.c @@ -0,0 +1,77 @@ +/* PR c/94040 - ICE on a call to an invalid redeclaration of strftime + { dg-do compile } + { dg-options "-Wall" } */ + +typedef __SIZE_TYPE__ size_t; + +struct tm; + +size_t strftime (char *, size_t, int *, struct tm *); // { dg-warning "-Wbuiltin-declaration-mismatch" } + +size_t call_strftime (char *d, size_t n, int *f, struct tm *t) +{ + size_t r = 0; + r += strftime (0, 0, 0, 0); + r += strftime (d, 0, 0, 0); + r += strftime (d, n, 0, 0); + r += strftime (d, n, f, 0); + r += strftime (d, n, f, t); + return r; +} + + +char* strchr (char*, char*); // { dg-warning "-Wbuiltin-declaration-mismatch" } + +// Verify that missing/extra qualifiers aren't diagnosed without -Wextra. + +int strcmp (char*, char*); +int strncmp (volatile char*, volatile char*, size_t); + +// Verify that a difference in pointers is diagnosed. + +size_t strlen (const char**); +// { dg-warning "-Wbuiltin-declaration-mismatch" "pointer" { target *-*-* } .-1 } + + size_t strnlen (const char* const*, size_t); +// { dg-warning "-Wbuiltin-declaration-mismatch" "pointer" { target *-*-* } .-1 } + + +// Verify that calls to the compatibly-redeclared built-ins are treated +// as those to the built-ins and diagnosed. + +int test_builtin_calls (size_t n) +{ + int r = 0; + r += strcmp ((char*)0, ""); // { dg-warning "\\\[-Wnonnull]" } + r += strcmp ("", (char*)0); // { dg-warning "\\\[-Wnonnull]" } + + r += strncmp ((char*)0, "", n); // { dg-warning "\\\[-Wnonnull]" } + r += strncmp ("", (char*)0, n); // { dg-warning "\\\[-Wnonnull]" } + + return r; +} + + +// Verify that calls to the incompatibly-redeclared built-ins are not +// treated as those to the built-ins by the middle-end. It doesn't +// matter if the front-end diagnoses them but the middle-end should +// not because it shouldn't recognize them as built-ins. + +#pragma GCC optimize "2" + +size_t test_nonbuiltin_calls (char *s, int c) +{ + void *null = 0; + + char *r; + r = strchr ((char*)null, s); + r = strchr (r, (char*)null); + *s = *r; // use the result + + size_t n = 0; + n += strftime (0, 0, 0, 0); + n += strlen ((const char**)null); + n += strnlen ((const char**)null, n); + + return n; +} diff --git a/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-15.c b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-15.c new file mode 100644 index 00000000000..3c32a5fc545 --- /dev/null +++ b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-15.c @@ -0,0 +1,56 @@ +/* PR c/94040 - ICE on a call to an invalid redeclaration of strftime + { dg-do compile } + { dg-options "-Wall -Wextra" } */ + +typedef __SIZE_TYPE__ size_t; + +struct tm; + +size_t strftime (const char *, size_t, char *, struct tm *); +// { dg-warning "-Wbuiltin-declaration-mismatch" "arg 1" { target *-*-* } .-1 } + +// Verify that missing/extra qualifiers are diagnosed with -Wextra. + +int strcmp (char*, const char*); +// { dg-warning "-Wbuiltin-declaration-mismatch" "arg 1" { target *-*-* } .-1 } + +int strncmp (const char*, volatile char*, size_t); +// { dg-warning "-Wbuiltin-declaration-mismatch" "arg 2" { target *-*-* } .-1 } + +size_t strlen (char*); +// { dg-warning "-Wbuiltin-declaration-mismatch" "arg 1" { target *-*-* } .-1 } + + +// Verify that calls to built-ins declared with missing/extra qualifiers +// are still treated as those to built-ins by the front-end. + +int test_builtin_calls_fe (size_t n) +{ + int r = 0; + r += strcmp ((char*)0, ""); // { dg-warning "\\\[-Wnonnull]" } + r += strcmp ("", (char*)0); // { dg-warning "\\\[-Wnonnull]" } + + r += strncmp ((char*)0, "", n); // { dg-warning "\\\[-Wnonnull]" } + r += strncmp ("", (char*)0, n); // { dg-warning "\\\[-Wnonnull]" } + + r += strlen ((char*)0); // { dg-warning "\\\[-Wnonnull]" } + return r; +} + + +// Ditto but by the middle-end. + +#pragma GCC optimize "2" + +int test_builtin_calls_me (void) +{ + char *null1 = 0; + char *null2 = null1; + char *null3 = null2; + + int r = 0; + r += strcmp (null1, "123"); // { dg-warning "\\\[-Wnonnull]" } + r += strncmp ("2345", null2, 4); // { dg-warning "\\\[-Wnonnull]" } + r += strlen (null3); // { dg-warning "\\\[-Wnonnull]" } + return r; +} diff --git a/gcc/testsuite/gcc.dg/pr62090.c b/gcc/testsuite/gcc.dg/pr62090.c index 53089cf1932..42f1345e646 100644 --- a/gcc/testsuite/gcc.dg/pr62090.c +++ b/gcc/testsuite/gcc.dg/pr62090.c @@ -15,3 +15,5 @@ log_bad_request () { b += sprintf (0, "foo"); } + +/* { dg-prune-output "\\\[-Wbuiltin-declaration-mismatch]" } */ diff --git a/gcc/testsuite/gcc.dg/pr89314.c b/gcc/testsuite/gcc.dg/pr89314.c index e35dd8c81e1..27b3a510bfd 100644 --- a/gcc/testsuite/gcc.dg/pr89314.c +++ b/gcc/testsuite/gcc.dg/pr89314.c @@ -2,7 +2,7 @@ /* { dg-do compile } */ /* { dg-options "-O2 -Wbuiltin-declaration-mismatch -Wextra" } */ -extern __SIZE_TYPE__ strlen (const float *); /* { dg-warning "mismatch in argument 1 type of built-in function" } */ +extern __SIZE_TYPE__ strlen (const float *); /* { dg-warning "\\\[-Wbuiltin-declaration-mismatch" } */ void bar (void); void

avoid treating more incompatible redeclarations as builtin-ins [PR94040]

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