From 71ad0b5dde449ee1f6b755a99f5c52152e375835 Mon Sep 17 00:00:00 2001 From: Martin Sebor Date: Wed, 16 Sep 2020 14:04:01 -0600 Subject: [PATCH] Detect conflicts between incompatible uses of the same attribute (PR c/78666). Resolves: PR c/78666 - conflicting attribute alloc_size accepted PR c/96126 - conflicting attribute section accepted on redeclaration gcc/c-family/ChangeLog: PR c/78666 PR c/96126 * c-attribs.c (validate_attr_args): New function. (validate_attr_arg): Same. (handle_section_attribute): Call it. Introduce a local variable. (handle_alloc_size_attribute): Same. (handle_alloc_align_attribute): Same. gcc/testsuite/ChangeLog: PR c/78666 PR c/96126 * gcc.dg/attr-alloc_align-5.c: New test. * gcc.dg/attr-alloc_size-13.c: New test. * gcc.dg/attr-section.c: New test. * c-c++-common/builtin-has-attribute-3.c: Add xfails due to expected warnings to be cleaned up. --- gcc/c-family/c-attribs.c | 193 ++++++++++++++++++--- .../c-c++-common/builtin-has-attribute-3.c | 18 +- gcc/testsuite/gcc.dg/attr-alloc_align-5.c | 23 +++ gcc/testsuite/gcc.dg/attr-alloc_size-13.c | 34 ++++ gcc/testsuite/gcc.dg/attr-section.c | 13 ++ 5 files changed, 248 insertions(+), 33 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/attr-alloc_align-5.c create mode 100644 gcc/testsuite/gcc.dg/attr-alloc_size-13.c create mode 100644 gcc/testsuite/gcc.dg/attr-section.c diff --git a/gcc/c-family/c-attribs.c b/gcc/c-family/c-attribs.c index 4920725..8c898ad 100644 --- a/gcc/c-family/c-attribs.c +++ b/gcc/c-family/c-attribs.c @@ -720,6 +720,134 @@ positional_argument (const_tree fntype, const_tree atname, tree pos, return pos; } +/* Return the first of DECL or TYPE attributes installed in NODE if it's + a DECL, or TYPE attributes if it's a TYPE, or null otherwise. */ + +static tree +decl_or_type_attrs (tree node) +{ + if (DECL_P (node)) + { + if (tree attrs = DECL_ATTRIBUTES (node)) + return attrs; + + tree type = TREE_TYPE (node); + return TYPE_ATTRIBUTES (type); + } + + if (TYPE_P (node)) + return TYPE_ATTRIBUTES (node); + + return NULL_TREE; +} + +/* Given a pair of NODEs for arbitrary DECLs or TYPEs, validate one or + two integral or string attribute arguments NEWARGS to be applied to + NODE[0] for the absence of conflicts with the same attribute arguments + already applied to NODE[1]. Issue a warning for conflicts and return + false. Otherwise, when no conflicts are found, return true. */ + +static bool +validate_attr_args (tree node[2], tree name, tree newargs[2]) +{ + /* First validate the arguments against those already applied to + the same declaration (or type). */ + tree self[2] = { node[0], node[0] }; + if (node[0] != node[1] && !validate_attr_args (self, name, newargs)) + return false; + + if (!node[1]) + return true; + + /* Extract the same attribute from the previous declaration or type. */ + tree prevattr = decl_or_type_attrs (node[1]); + const char* const namestr = IDENTIFIER_POINTER (name); + prevattr = lookup_attribute (namestr, prevattr); + if (!prevattr) + return true; + + /* Extract one or both attribute arguments. */ + tree prevargs[2]; + prevargs[0] = TREE_VALUE (TREE_VALUE (prevattr)); + prevargs[1] = TREE_CHAIN (TREE_VALUE (prevattr)); + if (prevargs[1]) + prevargs[1] = TREE_VALUE (prevargs[1]); + + /* Both arguments must be equal or, for the second pair, neither must + be provided to succeed. */ + bool arg1eq, arg2eq; + if (TREE_CODE (newargs[0]) == INTEGER_CST) + { + arg1eq = tree_int_cst_equal (newargs[0], prevargs[0]); + if (newargs[1] && prevargs[1]) + arg2eq = tree_int_cst_equal (newargs[1], prevargs[1]); + else + arg2eq = newargs[1] == prevargs[1]; + } + else if (TREE_CODE (newargs[0]) == STRING_CST) + { + const char *s0 = TREE_STRING_POINTER (newargs[0]); + const char *s1 = TREE_STRING_POINTER (prevargs[0]); + arg1eq = strcmp (s0, s1) == 0; + if (newargs[1] && prevargs[1]) + { + s0 = TREE_STRING_POINTER (newargs[1]); + s1 = TREE_STRING_POINTER (prevargs[1]); + arg2eq = strcmp (s0, s1) == 0; + } + else + arg2eq = newargs[1] == prevargs[1]; + } + else + gcc_unreachable (); + + if (arg1eq && arg2eq) + return true; + + /* If the two locations are different print a note pointing to + the previous one. */ + const location_t curloc = input_location; + const location_t prevloc = + DECL_P (node[1]) ? DECL_SOURCE_LOCATION (node[1]) : curloc; + + /* Format the attribute specification for convenience. */ + char newspec[80], prevspec[80]; + if (newargs[1]) + snprintf (newspec, sizeof newspec, "%s (%s, %s)", namestr, + print_generic_expr_to_str (newargs[0]), + print_generic_expr_to_str (newargs[1])); + else + snprintf (newspec, sizeof newspec, "%s (%s)", namestr, + print_generic_expr_to_str (newargs[0])); + + if (prevargs[1]) + snprintf (prevspec, sizeof prevspec, "%s (%s, %s)", namestr, + print_generic_expr_to_str (prevargs[0]), + print_generic_expr_to_str (prevargs[1])); + else + snprintf (prevspec, sizeof prevspec, "%s (%s)", namestr, + print_generic_expr_to_str (prevargs[0])); + + if (warning_at (curloc, OPT_Wattributes, + "ignoring attribute %qs because it conflicts " + "with previous %qs", + newspec, prevspec) + && curloc != prevloc) + inform (prevloc, "previous declaration here"); + + return false; +} + +/* Convenience wrapper for validate_attr_args to validate a single + attribute argument. Used by handlers for attributes that take + just a single argument. */ + +static bool +validate_attr_arg (tree node[2], tree name, tree newarg) +{ + tree argarray[2] = { newarg, NULL_TREE }; + return validate_attr_args (node, name, argarray); +} /* Attribute handlers common to C front ends. */ @@ -1889,11 +2017,13 @@ handle_mode_attribute (tree *node, tree name, tree args, struct attribute_spec.handler. */ static tree -handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args, - int ARG_UNUSED (flags), bool *no_add_attrs) +handle_section_attribute (tree *node, tree name, tree args, + int flags, bool *no_add_attrs) { tree decl = *node; tree res = NULL_TREE; + tree argval = TREE_VALUE (args); + const char* new_section_name; if (!targetm_common.have_named_sections) { @@ -1908,7 +2038,7 @@ handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args, goto fail; } - if (TREE_CODE (TREE_VALUE (args)) != STRING_CST) + if (TREE_CODE (argval) != STRING_CST) { error ("section attribute argument not a string constant"); goto fail; @@ -1923,15 +2053,17 @@ handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args, goto fail; } + new_section_name = TREE_STRING_POINTER (argval); + /* The decl may have already been given a section attribute from a previous declaration. Ensure they match. */ - if (DECL_SECTION_NAME (decl) != NULL - && strcmp (DECL_SECTION_NAME (decl), - TREE_STRING_POINTER (TREE_VALUE (args))) != 0) - { - error ("section of %q+D conflicts with previous declaration", *node); - goto fail; - } + if (const char* const old_section_name = DECL_SECTION_NAME (decl)) + if (strcmp (old_section_name, new_section_name) != 0) + { + error ("section of %q+D conflicts with previous declaration", + *node); + goto fail; + } if (VAR_P (decl) && !targetm.have_tls && targetm.emutls.tmpl_section @@ -1941,6 +2073,9 @@ handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args, goto fail; } + if (!validate_attr_arg (node, name, argval)) + goto fail; + res = targetm.handle_generic_attribute (node, name, args, flags, no_add_attrs); @@ -1948,7 +2083,7 @@ handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args, final processing. */ if (!(*no_add_attrs)) { - set_decl_section_name (decl, TREE_STRING_POINTER (TREE_VALUE (args))); + set_decl_section_name (decl, new_section_name); return res; } @@ -2905,15 +3040,15 @@ handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args), return NULL_TREE; } -/* Handle a "alloc_size" attribute; arguments as in - struct attribute_spec.handler. */ +/* Handle the "alloc_size (argpos1 [, argpos2])" function type attribute. + *NODE is the type of the function the attribute is being applied to. */ static tree handle_alloc_size_attribute (tree *node, tree name, tree args, int ARG_UNUSED (flags), bool *no_add_attrs) { - tree decl = *node; - tree rettype = TREE_TYPE (decl); + tree fntype = *node; + tree rettype = TREE_TYPE (fntype); if (!POINTER_TYPE_P (rettype)) { warning (OPT_Wattributes, @@ -2923,6 +3058,7 @@ handle_alloc_size_attribute (tree *node, tree name, tree args, return NULL_TREE; } + tree newargs[2] = { NULL_TREE, NULL_TREE }; for (int i = 1; args; ++i) { tree pos = TREE_VALUE (args); @@ -2931,30 +3067,36 @@ handle_alloc_size_attribute (tree *node, tree name, tree args, the argument number in diagnostics (since there's just one mentioning it is unnecessary and coule be confusing). */ tree next = TREE_CHAIN (args); - if (tree val = positional_argument (decl, name, pos, INTEGER_TYPE, + if (tree val = positional_argument (fntype, name, pos, INTEGER_TYPE, next || i > 1 ? i : 0)) - TREE_VALUE (args) = val; + { + TREE_VALUE (args) = val; + newargs[i - 1] = val; + } else { *no_add_attrs = true; - break; + return NULL_TREE; } args = next; } + if (!validate_attr_args (node, name, newargs)) + *no_add_attrs = true; + return NULL_TREE; } -/* Handle a "alloc_align" attribute; arguments as in - struct attribute_spec.handler. */ + +/* Handle an "alloc_align (argpos)" attribute. */ static tree handle_alloc_align_attribute (tree *node, tree name, tree args, int, bool *no_add_attrs) { - tree decl = *node; - tree rettype = TREE_TYPE (decl); + tree fntype = *node; + tree rettype = TREE_TYPE (fntype); if (!POINTER_TYPE_P (rettype)) { warning (OPT_Wattributes, @@ -2964,9 +3106,12 @@ handle_alloc_align_attribute (tree *node, tree name, tree args, int, return NULL_TREE; } - if (!positional_argument (*node, name, TREE_VALUE (args), INTEGER_TYPE)) - *no_add_attrs = true; + if (tree val = positional_argument (*node, name, TREE_VALUE (args), + INTEGER_TYPE)) + if (validate_attr_arg (node, name, val)) + return NULL_TREE; + *no_add_attrs = true; return NULL_TREE; } diff --git a/gcc/testsuite/c-c++-common/builtin-has-attribute-3.c b/gcc/testsuite/c-c++-common/builtin-has-attribute-3.c index 2a59501..5736bab 100644 --- a/gcc/testsuite/c-c++-common/builtin-has-attribute-3.c +++ b/gcc/testsuite/c-c++-common/builtin-has-attribute-3.c @@ -75,7 +75,7 @@ void test_alloc_align (void) A (0, fnone, alloc_align (1)); /* { dg-warning "\\\[-Wattributes" } */ A (0, falloc_size_1, alloc_align (1)); A (1, falloc_align_1, alloc_align (1)); - A (0, falloc_align_2, alloc_align (1)); + A (0, falloc_align_2, alloc_align (1)); /* { dg-bogus "\\\[-Wattributes" "pr?????" { xfail *-*-* } }" */ A (1, falloc_align_2, alloc_align (2)); } @@ -88,26 +88,26 @@ void test_alloc_size_malloc (void) A (0, falloc_align_1, alloc_size (1)); A (0, falloc_align_2, alloc_size (1)); A (1, falloc_size_1, alloc_size (1)); - A (0, falloc_size_1, alloc_size (2)); - A (0, falloc_size_2, alloc_size (1)); + A (0, falloc_size_1, alloc_size (2)); /* { dg-bogus "\\\[-Wattributes" "pr?????" { xfail *-*-* } }" */ + A (0, falloc_size_2, alloc_size (1)); /* { dg-bogus "\\\[-Wattributes" "pr?????" { xfail *-*-* } }" */ A (1, falloc_size_2, alloc_size (2)); A (1, falloc_size_2_4, alloc_size); /* It would probably make more sense to have the built-in return true only when both alloc_size arguments match, not just one or the other. */ - A (0, falloc_size_2_4, alloc_size (1)); - A (1, falloc_size_2_4, alloc_size (2)); - A (0, falloc_size_2_4, alloc_size (3)); - A (1, falloc_size_2_4, alloc_size (4)); + A (0, falloc_size_2_4, alloc_size (1)); /* { dg-bogus "\\\[-Wattributes" "pr?????" { xfail *-*-* } }" */ + A (1, falloc_size_2_4, alloc_size (2)); /* { dg-bogus "\\\[-Wattributes" "pr?????" { xfail *-*-* } }" */ + A (0, falloc_size_2_4, alloc_size (3)); /* { dg-bogus "\\\[-Wattributes" "pr?????" { xfail *-*-* } }" */ + A (1, falloc_size_2_4, alloc_size (4)); /* { dg-bogus "\\\[-Wattributes" "pr?????" { xfail *-*-* } }" */ A (1, falloc_size_2_4, alloc_size (2, 4)); extern ATTR (alloc_size (3)) void* fmalloc_size_3 (int, int, int); A (1, fmalloc_size_3, alloc_size); - A (0, fmalloc_size_3, alloc_size (1)); - A (0, fmalloc_size_3, alloc_size (2)); + A (0, fmalloc_size_3, alloc_size (1)); /* { dg-bogus "\\\[-Wattributes" "pr?????" { xfail *-*-* } }" */ + A (0, fmalloc_size_3, alloc_size (2)); /* { dg-bogus "\\\[-Wattributes" "pr?????" { xfail *-*-* } }" */ A (1, fmalloc_size_3, alloc_size (3)); A (0, fmalloc_size_3, malloc); diff --git a/gcc/testsuite/gcc.dg/attr-alloc_align-5.c b/gcc/testsuite/gcc.dg/attr-alloc_align-5.c new file mode 100644 index 0000000..d6f2bc1 --- /dev/null +++ b/gcc/testsuite/gcc.dg/attr-alloc_align-5.c @@ -0,0 +1,23 @@ +/* PR c/78666 - conflicting attribute alloc_size accepted + { dg-do compile } + { dg-options "-Wall" } */ + +#define A(pos) __attribute__ ((alloc_align (pos))) + +A (1) char* f2_1 (int, int); +A (1) char* f2_1 (int, int); // { dg-message "previous declaration here" } + +A (2) char* f2_1 (int, int); // { dg-warning "ignoring attribute 'alloc_align \\\(2\\\)' because it conflicts with previous 'alloc_align \\\(1\\\)'" } + + +A (2) char* f2_2 (int, int); +A (2) char* f2_2 (int, int); // { dg-message "previous declaration here" } + +A (1) char* f2_2 (int, int); // { dg-warning "ignoring attribute 'alloc_align \\\(1\\\)' because it conflicts with previous 'alloc_align \\\(2\\\)'" } + + +A (1) char* f3_1 (int, int, int); +A (1) char* f3_1 (int, int, int); // { dg-message "previous declaration here" } + +A (2) char* f3_1 (int, int, int); // { dg-warning "ignoring attribute 'alloc_align \\\(2\\\)' because it conflicts with previous 'alloc_align \\\(1\\\)'" } +A (3) char* f3_1 (int, int, int); // { dg-warning "ignoring attribute 'alloc_align \\\(3\\\)' because it conflicts with previous 'alloc_align \\\(1\\\)'" } diff --git a/gcc/testsuite/gcc.dg/attr-alloc_size-13.c b/gcc/testsuite/gcc.dg/attr-alloc_size-13.c new file mode 100644 index 0000000..df44f47 --- /dev/null +++ b/gcc/testsuite/gcc.dg/attr-alloc_size-13.c @@ -0,0 +1,34 @@ +/* PR c/78666 - conflicting attribute alloc_size accepted + { dg-do compile } + { dg-options "-Wall" } */ + +#define A(...) __attribute__ ((alloc_size (__VA_ARGS__))) + +A (1) char* f2_1 (int, int); +A (1) A (1) char* f2_1 (int, int); + +A (1) char* f2_1 (int, int); // { dg-message "previous declaration here" } + +A (2) char* f2_1 (int, int); // { dg-warning "ignoring attribute 'alloc_size \\\(2\\\)' because it conflicts with previous 'alloc_size \\\(1\\\)'" } + + +A (2) char* f2_2 (int, int); +A (2) char* f2_2 (int, int); // { dg-message "previous declaration here" } + +A (1) char* f2_2 (int, int); // { dg-warning "ignoring attribute 'alloc_size \\\(1\\\)' because it conflicts with previous 'alloc_size \\\(2\\\)'" } + + +A (1) char* f3_1 (int, int, int); +A (1) char* f3_1 (int, int, int); // { dg-message "previous declaration here" } + +A (2) char* f3_1 (int, int, int); // { dg-warning "ignoring attribute 'alloc_size \\\(2\\\)' because it conflicts with previous 'alloc_size \\\(1\\\)'" } +A (3) char* f3_1 (int, int, int); // { dg-warning "ignoring attribute 'alloc_size \\\(3\\\)' because it conflicts with previous 'alloc_size \\\(1\\\)'" } +A (1, 2) char* f3_1 (int, int, int); // { dg-warning "ignoring attribute 'alloc_size \\\(1, 2\\\)' because it conflicts with previous 'alloc_size \\\(1\\\)'" } +A (1, 3) char* f3_1 (int, int, int); // { dg-warning "ignoring attribute 'alloc_size \\\(1, 3\\\)' because it conflicts with previous 'alloc_size \\\(1\\\)'" } + + +typedef A (2, 3) char* F3_2_3 (int, int, int); +typedef A (2, 3) char* F3_2_3 (int, int, int); +typedef A (2, 3) A (2, 3) char* F3_2_3 (int, int, int); + +typedef A (1) char* F3_2_3 (int, int, int); // { dg-warning "ignoring attribute 'alloc_size \\\(1\\\)' because it conflicts with previous 'alloc_size \\\(2, 3\\\)'" } diff --git a/gcc/testsuite/gcc.dg/attr-section.c b/gcc/testsuite/gcc.dg/attr-section.c new file mode 100644 index 0000000..0062b54 --- /dev/null +++ b/gcc/testsuite/gcc.dg/attr-section.c @@ -0,0 +1,13 @@ +/* PR c/96126 - conflicting attribute section accepted on redeclaration + { dg-do compile } + { dg-options "-Wall" } + { dg-require-named-sections "" } */ + +__attribute__ ((section ("s1"))) void f1 (void); +__attribute__ ((section ("s2"))) void f1 (void); // { dg-warning "ignoring attribute 'section \\\(\"s2\"\\\)' because it conflicts with previous 'section \\\(\"s1\"\\\)'" } + +__attribute__ ((section ("s3"), section ("s4"))) +void f2 (void); // { dg-error "conflicts" } + +__attribute__ ((section ("s5"))) __attribute ((section ("s6"))) +void f3 (void); // { dg-error "conflicts" } -- 2.7.4