--Boundary-00=_zhPrFJVz3bdTgg3 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline On Tuesday, 16. January 2007 16:52, Gabriel Dos Reis wrote: > | Also, I am not sure whether you need testcases for "testing that is > | enabled by -Wall" and "testing that is disabled with -Wall > | -Wno-array-bounds". > you're free to add one. Ok, I've added testcases that check that the functionality is enabled for C and for C++. Attached for reference, regtest in progress. Is the patch OK if it passes? Thanks, Dirk --Boundary-00=_zhPrFJVz3bdTgg3 Content-Type: text/x-diff; charset="iso-8859-1"; name="array_bounds_vrp_6.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="array_bounds_vrp_6.patch" 2007-01-15 Dirk Mueller Richard Guenther PR diagnostic/8268 * doc/invoke.texi (Warray-bounds): Document -Warray-bounds. * common.opt (Warray-bounds): Add new warning option. * c-opts.c (c_common_handle_option): Define -Warray-bounds if -Wall is given. * Makefile.in: make tree-vrp.o depend on toplev.h * tree-vrp.c (vrp_finalize): Call check_array_refs if -Warray-bounds is enabled. (check_array_refs, check_array_bounds, check_array_ref): New. * gcc.dg/Warray-bounds.c: New testcase. * gcc.dg/Warray-bounds-2.c: New testcase. * g++.dg/warn/Warray-bounds.C: New testcase. * g++.dg/warn/Warray-bounds-2.C: New testcase. --- doc/invoke.texi (revision 120757) +++ doc/invoke.texi (working copy) @@ -222,8 +222,8 @@ Objective-C and Objective-C++ Dialects}. @item Warning Options @xref{Warning Options,,Options to Request or Suppress Warnings}. @gccoptlist{-fsyntax-only -pedantic -pedantic-errors @gol --w -Wextra -Wall -Waggregate-return -Walways-true -Wno-attributes @gol --Wc++-compat -Wcast-align -Wcast-qual -Wchar-subscripts @gol +-w -Wextra -Wall -Waggregate-return -Walways-true -Warray-bounds @gol +-Wno-attributes -Wc++-compat -Wcast-align -Wcast-qual -Wchar-subscripts @gol -Wclobbered -Wcomment @gol -Wconversion -Wno-deprecated-declarations @gol -Wdisabled-optimization -Wno-div-by-zero @gol @@ -2842,6 +2843,13 @@ compiler is using for optimization. Thi @option{-Wstrict-aliasing}, but it will also give a warning for some ambiguous cases that are safe. +@item -Warray-bounds +@opindex Wno-array-bounds +@opindex Warray-bounds +This option is only active when @option{-ftree-vrp} is active +(default for -O2 and above). It warns about subscripts to arrays +that are always out of bounds. This warning is enabled by @option{-Wall}. + @item -Wall @opindex Wall All of the above @samp{-W} options combined. This enables all the --- common.opt (revision 120757) +++ common.opt (working copy) @@ -61,6 +61,10 @@ Walways-true Common Var(warn_always_true) Warn about comparisons that always evaluate to true +Warray-bounds +Common Var(warn_array_bounds) +Warn if an array is accessed out of bounds + Wattributes Common Var(warn_attributes) Init(1) Warn about inappropriate attribute usage --- c-opts.c (revision 120757) +++ c-opts.c (working copy) @@ -396,6 +396,7 @@ c_common_handle_option (size_t scode, co warn_strict_aliasing = value; warn_string_literal_comparison = value; warn_always_true = value; + warn_array_bounds = value; /* Only warn about unknown pragmas that are not in system headers. */ --- Makefile.in (revision 120757) +++ Makefile.in (working copy) @@ -1862,7 +1862,7 @@ tree-vn.o : tree-vn.c $(CONFIG_H) $(SYST tree-vrp.o : tree-vrp.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(TREE_H) \ $(TREE_FLOW_H) tree-pass.h $(TREE_DUMP_H) $(DIAGNOSTIC_H) $(GGC_H) \ $(BASIC_BLOCK_H) tree-ssa-propagate.h $(FLAGS_H) $(TREE_DUMP_H) \ - $(CFGLOOP_H) $(SCEV_H) tree-chrec.h $(TIMEVAR_H) + $(CFGLOOP_H) $(SCEV_H) tree-chrec.h $(TIMEVAR_H) toplev.h tree-cfg.o : tree-cfg.c $(TREE_FLOW_H) $(CONFIG_H) $(SYSTEM_H) \ $(RTL_H) $(TREE_H) $(TM_P_H) $(EXPR_H) $(GGC_H) $(FLAGS_H) output.h \ $(DIAGNOSTIC_H) $(FUNCTION_H) $(TIMEVAR_H) $(TM_H) coretypes.h \ --- tree-vrp.c (revision 120757) +++ tree-vrp.c (working copy) @@ -32,6 +32,7 @@ Boston, MA 02110-1301, USA. */ #include "tree-dump.h" #include "timevar.h" #include "diagnostic.h" +#include "toplev.h" #include "cfgloop.h" #include "tree-scalar-evolution.h" #include "tree-ssa-propagate.h" @@ -3478,6 +3478,154 @@ insert_range_assertions (void) BITMAP_FREE (need_assert_for); } +/* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays + and "struct" hacks. If VRP can determine that the + array subscript is a contant, check if it is outside valid + range. If the array subscript is a RANGE, warn if it is + non-overlapping with valid range. + IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */ + +static void +check_array_ref (tree ref, location_t* locus, bool ignore_off_by_one) +{ + value_range_t* vr = NULL; + tree low_sub, up_sub; + tree low_bound, up_bound = array_ref_up_bound (ref); + + low_sub = up_sub = TREE_OPERAND (ref, 1); + + if (!up_bound || !locus || TREE_NO_WARNING (ref) + || TREE_CODE (up_bound) != INTEGER_CST + /* Can not check flexible arrays. */ + || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE + && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE + && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE) + /* Accesses after the end of arrays of size 0 (gcc + extension) and 1 are likely intentional ("struct + hack"). */ + || compare_tree_int (up_bound, 1) <= 0) + return; + + low_bound = array_ref_low_bound (ref); + + if (TREE_CODE (low_sub) == SSA_NAME) + { + vr = get_value_range (low_sub); + if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE) + { + low_sub = vr->type == VR_RANGE ? vr->max : vr->min; + up_sub = vr->type == VR_RANGE ? vr->min : vr->max; + } + } + + if (vr && vr->type == VR_ANTI_RANGE) + { + if (TREE_CODE (up_sub) == INTEGER_CST + && tree_int_cst_lt (up_bound, up_sub) + && TREE_CODE (low_sub) == INTEGER_CST + && tree_int_cst_lt (low_sub, low_bound)) + { + warning (OPT_Warray_bounds, + "%Harray subscript is outside array bounds", locus); + TREE_NO_WARNING (ref) = 1; + } + } + else if (TREE_CODE (up_sub) == INTEGER_CST + && tree_int_cst_lt (up_bound, up_sub) + && !tree_int_cst_equal (up_bound, up_sub) + && (!ignore_off_by_one + || !tree_int_cst_equal (int_const_binop (PLUS_EXPR, + up_bound, + integer_one_node, + 0), + up_sub))) + { + warning (OPT_Warray_bounds, "%Harray subscript is above array bounds", + locus); + TREE_NO_WARNING (ref) = 1; + } + else if (TREE_CODE (low_sub) == INTEGER_CST + && tree_int_cst_lt (low_sub, low_bound)) + { + warning (OPT_Warray_bounds, "%Harray subscript is below array bounds", + locus); + TREE_NO_WARNING (ref) = 1; + } +} + +/* walk_tree() callback that checks if *TP is + an ARRAY_REF inside an ADDR_EXPR (in which an array + subscript one outside the valid range is allowed). Call + check_array_ref for each ARRAY_REF found. The location is + passed in DATA. */ + +static tree +check_array_bounds (tree *tp, int *walk_subtree, void *data) +{ + tree t = *tp; + location_t *location = EXPR_LOCUS ((tree) data); + + *walk_subtree = TRUE; + + if (TREE_CODE (t) == ARRAY_REF) + check_array_ref (t, location, false /*ignore_off_by_one*/); + else if (TREE_CODE (t) == ADDR_EXPR) + { + t = TREE_OPERAND (t, 0); + + /* Don't warn on statements like + ssa_name = 500 + &array[-200] which are sometimes + produced by various optimizing passes. */ + if (TREE_CODE ((tree)data) == GIMPLE_MODIFY_STMT + && BINARY_CLASS_P (GIMPLE_STMT_OPERAND ((tree)data, 1))) + { + *walk_subtree = FALSE; + return NULL_TREE; + } + while (handled_component_p (t)) + { + if (TREE_CODE (t) == ARRAY_REF) + check_array_ref (t, location, true /*ignore_off_by_one*/); + t = TREE_OPERAND (t, 0); + } + *walk_subtree = FALSE; + } + + return NULL_TREE; +} + +/* Walk over all statements of all reachable BBs and call check_array_bounds + on them. */ + +static void +check_all_array_refs (void) +{ + basic_block bb; + block_stmt_iterator si; + + FOR_EACH_BB (bb) + { + /* Skip bb's that are clearly unreachable. */ + if (single_pred_p (bb)) + { + basic_block pred_bb = EDGE_PRED (bb, 0)->src; + tree ls = NULL_TREE; + + if (!bsi_end_p (bsi_last (pred_bb))) + ls = bsi_stmt (bsi_last (pred_bb)); + + if (ls && TREE_CODE (ls) == COND_EXPR + && ((COND_EXPR_COND (ls) == boolean_false_node + && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE)) + || (COND_EXPR_COND (ls) == boolean_true_node + && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE)))) + continue; + } + for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si)) + walk_tree (bsi_stmt_ptr (si), check_array_bounds, + bsi_stmt (si), NULL); + } +} /* Convert range assertion expressions into the implied copies and copy propagate away the copies. Doing the trivial copy propagation @@ -4797,6 +4945,9 @@ vrp_finalize (void) substitute_and_fold (single_val_range, true); + if (warn_array_bounds) + check_all_array_refs(); + /* We must identify jump threading opportunities before we release the datastructures built by VRP. */ identify_jump_threads (); --- testsuite/gcc.dg/Warray-bounds.c (revision 0) +++ testsuite/gcc.dg/Warray-bounds.c (revision 0) @@ -0,0 +1,94 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -Warray-bounds" } */ + +int a[10]; + +static inline int n(void) { + __SIZE_TYPE__ strlen(const char *s); + return strlen("12345"); +} + +void g(int *p); +void h(int p); + +int* f(void) { + int b[10]; + int i; + struct { + int c[10]; + } c; + + a[-1] = 0; /* { dg-warning "array subscript" } */ + a[ 0] = 0; + a[ 1] = 0; + + + a[ 9] = 0; + a[10] = 0; /* { dg-warning "array subscript" } */ + a[11] = 0; /* { dg-warning "array subscript" } */ + a[2 * n() - 11] = 0; /* { dg-warning "array subscript" } */ + a[2 * n() - 10] = 0; + a[2 * n() - 1] = 0; + a[2 * n() - 0] = 0; /* { dg-warning "array subscript" } */ + + b[-1] = 0; /* { dg-warning "array subscript" } */ + b[ 0] = 0; + b[ 1] = 0; + b[ 9] = 0; + b[10] = 0; /* { dg-warning "array subscript" } */ + b[11] = 0; /* { dg-warning "array subscript" } */ + b[2 * n() - 11] = 0; /* { dg-warning "array subscript" } */ + b[2 * n() - 10] = 0; + b[2 * n() - 1] = 0; + b[2 * n() - 0] = 0; /* { dg-warning "array subscript" } */ + + c.c[-1] = 0; /* { dg-warning "array subscript" } */ + c.c[ 0] = 0; + c.c[ 1] = 0; + c.c[ 9] = 0; + c.c[10] = 0; /* { dg-warning "array subscript" } */ + c.c[11] = 0; /* { dg-warning "array subscript" } */ + c.c[2 * n() - 11] = 0; /* { dg-warning "array subscript" } */ + c.c[2 * n() - 10] = 0; + c.c[2 * n() - 1] = 0; + c.c[2 * n() - 0] = 0; /* { dg-warning "array subscript" } */ + + g(&a[8]); + g(&a[9]); + g(&a[10]); + g(&a[11]); /* { dg-warning "array subscript" } */ + g(&a[-30]+10); /* { dg-warning "array subscript" } */ + g(&a[-30]+30); + + g(&b[10]); + g(&c.c[10]); + g(&a[11]); /* { dg-warning "array subscript" } */ + g(&b[11]); /* { dg-warning "array subscript" } */ + g(&c.c[11]); /* { dg-warning "array subscript" } */ + + g(&a[0]); + g(&b[0]); + g(&c.c[0]); + + g(&a[-1]); /* { dg-warning "array subscript" } */ + g(&b[-1]); /* { dg-warning "array subscript" } */ + h(sizeof a[-1]); + h(sizeof a[10]); + h(sizeof b[-1]); + h(sizeof b[10]); + h(sizeof c.c[-1]); + h(sizeof c.c[10]); + + if (10 < 10) + a[10] = 0; + if (10 < 10) + b[10] = 0; + if (-1 >= 0) + c.c[-1] = 0; + + for (i = 20; i < 30; ++i) + a[i] = 1; /* { dg-warning "array subscript" } */ + + return a; +} + Index: testsuite/gcc.dg/Warray-bounds-2.c =================================================================== --- testsuite/gcc.dg/Warray-bounds-2.c (revision 0) +++ testsuite/gcc.dg/Warray-bounds-2.c (revision 0) @@ -0,0 +1,13 @@ +/* { dg-do compile } */ +/* Test that -Warray-bounds is enabled by -Wall */ +/* { dg-options "-O2 -Wall" } */ + +int a[10]; + +int* f(void) { + + a[-1] = 0; /* { dg-warning "array subscript" } */ + + return a; +} + Index: testsuite/g++.dg/warn/Warray-bounds.C =================================================================== --- testsuite/g++.dg/warn/Warray-bounds.C (revision 0) +++ testsuite/g++.dg/warn/Warray-bounds.C (revision 0) @@ -0,0 +1,91 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -Warray-bounds" } */ + +int a[10]; + +static inline int n(void) { + __SIZE_TYPE__ strlen(const char *s); + return strlen("12345"); +} + +void g(int *p); +void h(int p); + +int* f(void) { + int b[10]; + int i; + struct { + int c[10]; + } c; + + a[-1] = 0; /* { dg-warning "array subscript" } */ + a[ 0] = 0; + a[ 1] = 0; + + + a[ 9] = 0; + a[10] = 0; /* { dg-warning "array subscript" } */ + a[11] = 0; /* { dg-warning "array subscript" } */ + a[2 * n() - 11] = 0; /* { dg-warning "array subscript" } */ + a[2 * n() - 10] = 0; + a[2 * n() - 1] = 0; + a[2 * n() - 0] = 0; /* { dg-warning "array subscript" } */ + + b[-1] = 0; /* { dg-warning "array subscript" } */ + b[ 0] = 0; + b[ 1] = 0; + b[ 9] = 0; + b[10] = 0; /* { dg-warning "array subscript" } */ + b[11] = 0; /* { dg-warning "array subscript" } */ + b[2 * n() - 11] = 0; /* { dg-warning "array subscript" } */ + b[2 * n() - 10] = 0; + b[2 * n() - 1] = 0; + b[2 * n() - 0] = 0; /* { dg-warning "array subscript" } */ + + c.c[-1] = 0; /* { dg-warning "array subscript" } */ + c.c[ 0] = 0; + c.c[ 1] = 0; + c.c[ 9] = 0; + c.c[10] = 0; /* { dg-warning "array subscript" } */ + c.c[11] = 0; /* { dg-warning "array subscript" } */ + c.c[2 * n() - 11] = 0; /* { dg-warning "array subscript" } */ + c.c[2 * n() - 10] = 0; + c.c[2 * n() - 1] = 0; + c.c[2 * n() - 0] = 0; /* { dg-warning "array subscript" } */ + + g(&a[8]); + g(&a[9]); + g(&a[10]); + g(&a[11]); /* { dg-warning "array subscript" } */ + g(&a[-30]+10); /* { dg-warning "array subscript" } */ + g(&a[-30]+30); + + g(&b[10]); + g(&c.c[10]); + g(&a[11]); /* { dg-warning "array subscript" } */ + g(&b[11]); /* { dg-warning "array subscript" } */ + g(&c.c[11]); /* { dg-warning "array subscript" } */ + + g(&a[0]); + g(&b[0]); + g(&c.c[0]); + + g(&a[-1]); /* { dg-warning "array subscript" } */ + g(&b[-1]); /* { dg-warning "array subscript" } */ + h(sizeof a[-1]); + h(sizeof a[10]); + h(sizeof b[-1]); + h(sizeof b[10]); + h(sizeof c.c[-1]); + h(sizeof c.c[10]); + + if (10 < 10) + a[10] = 0; + if (10 < 10) + b[10] = 0; + if (-1 >= 0) + c.c[-1] = 0; + + return a; +} + Index: testsuite/g++.dg/warn/Warray-bounds-2.C =================================================================== --- testsuite/g++.dg/warn/Warray-bounds-2.C (revision 0) +++ testsuite/g++.dg/warn/Warray-bounds-2.C (revision 0) @@ -0,0 +1,13 @@ +/* { dg-do compile } */ +/* Test that -Warray-bounds is enabled by -Wall */ +/* { dg-options "-O2 -Wall" } */ + +int a[10]; + +int* f(void) { + + a[-1] = 0; /* { dg-warning "array subscript" } */ + + return a; +} + --Boundary-00=_zhPrFJVz3bdTgg3--