From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2209) id 6CA173858D1E; Thu, 10 Feb 2022 18:01:51 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 6CA173858D1E MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: David Malcolm To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-7184] analyzer: handle more casts of string literals [PR98797] X-Act-Checkin: gcc X-Git-Author: David Malcolm X-Git-Refname: refs/heads/master X-Git-Oldrev: b32305b41dcafc5fb6974c0da3ce2f62251afdbf X-Git-Newrev: 2ac7b19f1e9219f46ccf55f25d8acb3e02e9a2d4 Message-Id: <20220210180151.6CA173858D1E@sourceware.org> Date: Thu, 10 Feb 2022 18:01:51 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Feb 2022 18:01:51 -0000 https://gcc.gnu.org/g:2ac7b19f1e9219f46ccf55f25d8acb3e02e9a2d4 commit r12-7184-g2ac7b19f1e9219f46ccf55f25d8acb3e02e9a2d4 Author: David Malcolm Date: Wed Feb 9 19:06:15 2022 -0500 analyzer: handle more casts of string literals [PR98797] gcc/analyzer/ChangeLog: PR analyzer/98797 * region-model-manager.cc (region_model_manager::maybe_fold_sub_svalue): Generalize getting individual chars of a STRING_CST from element_region to any subregion which is a concrete access of a single byte from its parent region. * region.cc (region::get_relative_concrete_byte_range): New. * region.h (region::get_relative_concrete_byte_range): New decl. gcc/testsuite/ChangeLog: PR analyzer/98797 * gcc.dg/analyzer/casts-1.c: Mark xfails as fixed; add further test coverage for casts of string literals. Signed-off-by: David Malcolm Diff: --- gcc/analyzer/region-model-manager.cc | 19 +++++++++----- gcc/analyzer/region.cc | 28 ++++++++++++++++++++ gcc/analyzer/region.h | 6 +++++ gcc/testsuite/gcc.dg/analyzer/casts-1.c | 45 +++++++++++++++++++++++++++------ 4 files changed, 84 insertions(+), 14 deletions(-) diff --git a/gcc/analyzer/region-model-manager.cc b/gcc/analyzer/region-model-manager.cc index 010ad078849..d7156c5499f 100644 --- a/gcc/analyzer/region-model-manager.cc +++ b/gcc/analyzer/region-model-manager.cc @@ -782,15 +782,22 @@ region_model_manager::maybe_fold_sub_svalue (tree type, /* Handle getting individual chars from a STRING_CST. */ if (tree cst = parent_svalue->maybe_get_constant ()) if (TREE_CODE (cst) == STRING_CST) - if (const element_region *element_reg - = subregion->dyn_cast_element_region ()) - { - const svalue *idx_sval = element_reg->get_index (); - if (tree cst_idx = idx_sval->maybe_get_constant ()) + { + /* If we have a concrete 1-byte access within the parent region... */ + byte_range subregion_bytes (0, 0); + if (subregion->get_relative_concrete_byte_range (&subregion_bytes) + && subregion_bytes.m_size_in_bytes == 1) + { + /* ...then attempt to get that char from the STRING_CST. */ + HOST_WIDE_INT hwi_start_byte + = subregion_bytes.m_start_byte_offset.to_shwi (); + tree cst_idx + = build_int_cst_type (size_type_node, hwi_start_byte); if (const svalue *char_sval = maybe_get_char_from_string_cst (cst, cst_idx)) return get_or_create_cast (type, char_sval); - } + } + } if (const initial_svalue *init_sval = parent_svalue->dyn_cast_initial_svalue ()) diff --git a/gcc/analyzer/region.cc b/gcc/analyzer/region.cc index 0adc75e577d..5ac24fb9f9b 100644 --- a/gcc/analyzer/region.cc +++ b/gcc/analyzer/region.cc @@ -539,6 +539,34 @@ region::get_relative_concrete_offset (bit_offset_t *) const return false; } +/* Attempt to get the position and size of this region expressed as a + concrete range of bytes relative to its parent. + If successful, return true and write to *OUT. + Otherwise return false. */ + +bool +region::get_relative_concrete_byte_range (byte_range *out) const +{ + /* We must have a concrete offset relative to the parent. */ + bit_offset_t rel_bit_offset; + if (!get_relative_concrete_offset (&rel_bit_offset)) + return false; + /* ...which must be a whole number of bytes. */ + if (rel_bit_offset % BITS_PER_UNIT != 0) + return false; + byte_offset_t start_byte_offset = rel_bit_offset / BITS_PER_UNIT; + + /* We must have a concrete size, which must be a whole number + of bytes. */ + byte_size_t num_bytes; + if (!get_byte_size (&num_bytes)) + return false; + + /* Success. */ + *out = byte_range (start_byte_offset, num_bytes); + return true; +} + /* Dump a description of this region to stderr. */ DEBUG_FUNCTION void diff --git a/gcc/analyzer/region.h b/gcc/analyzer/region.h index 53112175266..2f987e49fa8 100644 --- a/gcc/analyzer/region.h +++ b/gcc/analyzer/region.h @@ -182,6 +182,12 @@ public: Otherwise return false. */ virtual bool get_relative_concrete_offset (bit_offset_t *out) const; + /* Attempt to get the position and size of this region expressed as a + concrete range of bytes relative to its parent. + If successful, return true and write to *OUT. + Otherwise return false. */ + bool get_relative_concrete_byte_range (byte_range *out) const; + void get_subregions_for_binding (region_model_manager *mgr, bit_offset_t start_bit_offset, diff --git a/gcc/testsuite/gcc.dg/analyzer/casts-1.c b/gcc/testsuite/gcc.dg/analyzer/casts-1.c index 15cd85f77cf..7e4af384971 100644 --- a/gcc/testsuite/gcc.dg/analyzer/casts-1.c +++ b/gcc/testsuite/gcc.dg/analyzer/casts-1.c @@ -13,6 +13,14 @@ struct s2 char arr[4]; }; +struct s3 +{ + struct inner { + char a; + char b; + } arr[2]; +}; + void test_1 () { struct s1 x = {'A', 'B', 'C', 'D'}; @@ -24,10 +32,16 @@ void test_1 () __analyzer_eval (((struct s2 *)&x)->arr[1] == 'B'); /* { dg-warning "TRUE" } */ __analyzer_eval (((struct s2 *)&x)->arr[2] == 'C'); /* { dg-warning "TRUE" } */ __analyzer_eval (((struct s2 *)&x)->arr[3] == 'D'); /* { dg-warning "TRUE" } */ + struct s3 *p3 = (struct s3 *)&x; + __analyzer_eval (p3->arr[0].a == 'A'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p3->arr[0].b == 'B'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p3->arr[1].a == 'C'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p3->arr[1].b == 'D'); /* { dg-warning "TRUE" } */ ((struct s2 *)&x)->arr[1] = '#'; __analyzer_eval (((struct s2 *)&x)->arr[1] == '#'); /* { dg-warning "TRUE" } */ __analyzer_eval (x.b == '#'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p3->arr[0].b == '#'); /* { dg-warning "TRUE" } */ } void test_2 () @@ -38,12 +52,27 @@ void test_2 () __analyzer_eval (x.arr[2] == 'C'); /* { dg-warning "TRUE" } */ __analyzer_eval (x.arr[3] == 'D'); /* { dg-warning "TRUE" } */ struct s1 *p = (struct s1 *)&x; - __analyzer_eval (p->a == 'A'); /* { dg-warning "TRUE" "true" { xfail *-*-* } } */ - /* { dg-bogus "UNKNOWN" "unknown" { xfail *-*-* } .-1 } */ - __analyzer_eval (p->b == 'B'); /* { dg-warning "TRUE" "true" { xfail *-*-* } } */ - /* { dg-bogus "UNKNOWN" "unknown" { xfail *-*-* } .-1 } */ - __analyzer_eval (p->c == 'C'); /* { dg-warning "TRUE" "true" { xfail *-*-* } } */ - /* { dg-bogus "UNKNOWN" "unknown" { xfail *-*-* } .-1 } */ - __analyzer_eval (p->d == 'D'); /* { dg-warning "TRUE" "true" { xfail *-*-* } } */ - /* { dg-bogus "UNKNOWN" "unknown" { xfail *-*-* } .-1 } */ + __analyzer_eval (p->a == 'A'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p->b == 'B'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p->c == 'C'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p->d == 'D'); /* { dg-warning "TRUE" } */ +} + +void test_3 () +{ + struct s3 x = {'A', 'B', 'C', 'D'}; + __analyzer_eval (x.arr[0].a == 'A'); /* { dg-warning "TRUE" } */ + __analyzer_eval (x.arr[0].b == 'B'); /* { dg-warning "TRUE" } */ + __analyzer_eval (x.arr[1].a == 'C'); /* { dg-warning "TRUE" } */ + __analyzer_eval (x.arr[1].b == 'D'); /* { dg-warning "TRUE" } */ + struct s1 *p1 = (struct s1 *)&x; + __analyzer_eval (p1->a == 'A'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p1->b == 'B'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p1->c == 'C'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p1->d == 'D'); /* { dg-warning "TRUE" } */ + struct s2 *p2 = (struct s2 *)&x; + __analyzer_eval (p2->arr[0] == 'A'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p2->arr[1] == 'B'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p2->arr[2] == 'C'); /* { dg-warning "TRUE" } */ + __analyzer_eval (p2->arr[3] == 'D'); /* { dg-warning "TRUE" } */ }