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From: David Malcolm <dmalcolm@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-4429] diagnostics: tweak diagnostic_path::interprocedural_p [PR106626] Date: Thu, 1 Dec 2022 02:31:32 +0000 (GMT) [thread overview] Message-ID: <20221201023132.9D3423852C52@sourceware.org> (raw) https://gcc.gnu.org/g:1d86af242bc4a8e68aebf1f3b8c985f2d17fa791 commit r13-4429-g1d86af242bc4a8e68aebf1f3b8c985f2d17fa791 Author: David Malcolm <dmalcolm@redhat.com> Date: Wed Nov 30 21:26:43 2022 -0500 diagnostics: tweak diagnostic_path::interprocedural_p [PR106626] The region-creation event at the start of... <source>: In function 'int_arr_write_element_after_end_off_by_one': <source>:14:11: warning: buffer overflow [CWE-787] [-Wanalyzer-out-of-bounds] 14 | arr[10] = x; | ~~~~~~~~^~~ event 1 | | 10 | int32_t arr[10]; | | ^~~ | | | | | (1) capacity is 40 bytes | +--> 'int_arr_write_element_after_end_off_by_one': events 2-3 | | 12 | void int_arr_write_element_after_end_off_by_one(int32_t x) | | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | | | | | (2) entry to 'int_arr_write_element_after_end_off_by_one' | 13 | { | 14 | arr[10] = x; /* { dg-line line } */ | | ~~~~~~~~~~~ | | | | | (3) out-of-bounds write from byte 40 till byte 43 but 'arr' ends at byte 40 | <source>:14:11: note: write of 4 bytes to beyond the end of 'arr' 14 | arr[10] = x; | ~~~~~~~~^~~ <source>:14:11: note: valid subscripts for 'arr' are '[0]' to '[9]' ...makes diagnostic_manager::finish_pruning consider the path to be interprocedural, and so it doesn't prune the function entry event. This patch tweaks diagnostic_path::interprocedural_p to ignore leading events outside of any function, so that it considers the path to be intraprocedural, and thus diagnostic_manager::finish_pruning prunes the function entry event, leading to this simpler output: <source>: In function 'int_arr_write_element_after_end_off_by_one': <source>:14:11: warning: buffer overflow [CWE-787] [-Wanalyzer-out-of-bounds] 14 | arr[10] = x; | ~~~~~~~~^~~ event 1 | | 10 | int32_t arr[10]; | | ^~~ | | | | | (1) capacity is 40 bytes | +--> 'int_arr_write_element_after_end_off_by_one': event 2 | | 14 | arr[10] = x; | | ~~~~~~~~^~~ | | | | | (2) out-of-bounds write from byte 40 till byte 43 but 'arr' ends at byte 40 | <source>:14:11: note: write of 4 bytes to beyond the end of 'arr' <source>:14:11: note: valid subscripts for 'arr' are '[0]' to '[9]' gcc/ChangeLog: PR analyzer/106626 * diagnostic-path.h (diagnostic_path::get_first_event_in_a_function): New decl. * diagnostic.cc (diagnostic_path::get_first_event_in_a_function): New. (diagnostic_path::interprocedural_p): Ignore leading events that are outside of any function. gcc/testsuite/ChangeLog: PR analyzer/106626 * gcc.dg/analyzer/out-of-bounds-multiline-1.c: New test. Signed-off-by: David Malcolm <dmalcolm@redhat.com> Diff: --- gcc/diagnostic-path.h | 3 ++ gcc/diagnostic.cc | 37 ++++++++++++++++++++-- .../gcc.dg/analyzer/out-of-bounds-multiline-1.c | 37 ++++++++++++++++++++++ 3 files changed, 74 insertions(+), 3 deletions(-) diff --git a/gcc/diagnostic-path.h b/gcc/diagnostic-path.h index 8ce4ff763d4..aa5cda8c23a 100644 --- a/gcc/diagnostic-path.h +++ b/gcc/diagnostic-path.h @@ -167,6 +167,9 @@ class diagnostic_path virtual const diagnostic_event & get_event (int idx) const = 0; bool interprocedural_p () const; + +private: + bool get_first_event_in_a_function (unsigned *out_idx) const; }; /* Concrete subclasses. */ diff --git a/gcc/diagnostic.cc b/gcc/diagnostic.cc index a9562a815b1..322515b3242 100644 --- a/gcc/diagnostic.cc +++ b/gcc/diagnostic.cc @@ -939,18 +939,49 @@ diagnostic_event::meaning::maybe_get_property_str (enum property p) /* class diagnostic_path. */ +/* Subroutint of diagnostic_path::interprocedural_p. + Look for the first event in this path that is within a function + i.e. has a non-NULL fndecl, and a non-zero stack depth. + If found, write its index to *OUT_IDX and return true. + Otherwise return false. */ + +bool +diagnostic_path::get_first_event_in_a_function (unsigned *out_idx) const +{ + const unsigned num = num_events (); + for (unsigned i = 0; i < num; i++) + { + if (!(get_event (i).get_fndecl () == NULL + && get_event (i).get_stack_depth () == 0)) + { + *out_idx = i; + return true; + } + } + return false; +} + /* Return true if the events in this path involve more than one function, or false if it is purely intraprocedural. */ bool diagnostic_path::interprocedural_p () const { + /* Ignore leading events that are outside of any function. */ + unsigned first_fn_event_idx; + if (!get_first_event_in_a_function (&first_fn_event_idx)) + return false; + + const diagnostic_event &first_fn_event = get_event (first_fn_event_idx); + tree first_fndecl = first_fn_event.get_fndecl (); + int first_fn_stack_depth = first_fn_event.get_stack_depth (); + const unsigned num = num_events (); - for (unsigned i = 0; i < num; i++) + for (unsigned i = first_fn_event_idx + 1; i < num; i++) { - if (get_event (i).get_fndecl () != get_event (0).get_fndecl ()) + if (get_event (i).get_fndecl () != first_fndecl) return true; - if (get_event (i).get_stack_depth () != get_event (0).get_stack_depth ()) + if (get_event (i).get_stack_depth () != first_fn_stack_depth) return true; } return false; diff --git a/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-multiline-1.c b/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-multiline-1.c new file mode 100644 index 00000000000..25301e9e2ff --- /dev/null +++ b/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-multiline-1.c @@ -0,0 +1,37 @@ +/* Integration test of how the execution path looks for + -Wanalyzer-out-of-bounds. */ + +/* { dg-additional-options "-fdiagnostics-show-path-depths" } */ +/* { dg-additional-options "-fdiagnostics-path-format=inline-events -fdiagnostics-show-caret" } */ + + +#include <stdint.h> + +int32_t arr[10]; + +void int_arr_write_element_after_end_off_by_one(int32_t x) +{ + arr[10] = x; /* { dg-line line } */ +} +/* { dg-warning "buffer overflow" "warning" { target *-*-* } line } */ +/* { dg-message "valid subscripts for 'arr' are '\\\[0\\\]' to '\\\[9\\\]'" "valid subscript note" { target *-*-* } line } */ + + +/* { dg-begin-multiline-output "" } + arr[10] = x; + ~~~~~~~~^~~ + event 1 (depth 0) + | + | int32_t arr[10]; + | ^~~ + | | + | (1) capacity is 40 bytes + | + +--> 'int_arr_write_element_after_end_off_by_one': event 2 (depth 1) + | + | arr[10] = x; + | ~~~~~~~~^~~ + | | + | (2) out-of-bounds write from byte 40 till byte 43 but 'arr' ends at byte 40 + | + { dg-end-multiline-output "" } */
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