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Diffstat (limited to 'gcc/testsuite/gcc.dg/plugin/selfassign.c')
| -rw-r--r-- | gcc/testsuite/gcc.dg/plugin/selfassign.c | 365 |
1 files changed, 365 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/plugin/selfassign.c b/gcc/testsuite/gcc.dg/plugin/selfassign.c new file mode 100644 index 00000000000..6fbce83c01d --- /dev/null +++ b/gcc/testsuite/gcc.dg/plugin/selfassign.c @@ -0,0 +1,365 @@ +/* This plugin contains an analysis pass that detects and warns about + self-assignment statements. */ +/* { dg-options "-O" } */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "toplev.h" +#include "basic-block.h" +#include "gimple.h" +#include "tree.h" +#include "tree-pass.h" +#include "intl.h" +#include "gcc-plugin.h" + + +/* Indicate whether to check overloaded operator '=', which is performed by + default. To disable it, use -fplugin-arg-NAME-no-check-operator-eq. */ +bool check_operator_eq = true; + +/* Given a rhs EXPR of a gimple assign statement, if it is + - SSA_NAME : returns its var decl, or, if it is a temp variable, + returns the rhs of its SSA def statement. + - VAR_DECL, PARM_DECL, FIELD_DECL, or a reference expression : + returns EXPR itself. + - any other expression : returns NULL_TREE. */ + +static tree +get_real_ref_rhs (tree expr) +{ + switch (TREE_CODE (expr)) + { + case SSA_NAME: + { + /* Given a self-assign statement, say foo.x = foo.x, + the IR (after SSA) looks like: + + D.1797_14 = foo.x; + foo.x ={v} D.1797_14; + + So if the rhs EXPR is an SSA_NAME of a temp variable, + e.g. D.1797_14, we need to grab the rhs of its SSA def + statement (i.e. foo.x). */ + tree vdecl = SSA_NAME_VAR (expr); + if (DECL_ARTIFICIAL (vdecl) + && !gimple_nop_p (SSA_NAME_DEF_STMT (expr))) + { + gimple def_stmt = SSA_NAME_DEF_STMT (expr); + /* We are only interested in an assignment with a single + rhs operand because if it is not, the original assignment + will not possibly be a self-assignment. */ + if (is_gimple_assign (def_stmt) + && (get_gimple_rhs_class (gimple_assign_rhs_code (def_stmt)) + == GIMPLE_SINGLE_RHS)) + return get_real_ref_rhs (gimple_assign_rhs1 (def_stmt)); + else + return NULL_TREE; + } + else + return vdecl; + } + case VAR_DECL: + case PARM_DECL: + case FIELD_DECL: + case COMPONENT_REF: + case INDIRECT_REF: + case ARRAY_REF: + return expr; + default: + return NULL_TREE; + } +} + +/* Given an expression tree, EXPR, that may contains SSA names, returns an + equivalent tree with the SSA names converted to var/parm/field decls + so that it can be used with '%E' format modifier when emitting warning + messages. + + This function currently only supports VAR/PARM/FIELD_DECL, reference + expressions (COMPONENT_REF, INDIRECT_REF, ARRAY_REF), integer constant, + and SSA_NAME. If EXPR contains any other tree nodes (e.g. an arithmetic + expression appears in array index), NULL_TREE is returned. */ + +static tree +get_non_ssa_expr (tree expr) +{ + switch (TREE_CODE (expr)) + { + case VAR_DECL: + case PARM_DECL: + case FIELD_DECL: + { + if (DECL_NAME (expr)) + return expr; + else + return NULL_TREE; + } + case COMPONENT_REF: + { + tree base, orig_base = TREE_OPERAND (expr, 0); + tree component, orig_component = TREE_OPERAND (expr, 1); + base = get_non_ssa_expr (orig_base); + if (!base) + return NULL_TREE; + component = get_non_ssa_expr (orig_component); + if (!component) + return NULL_TREE; + /* If either BASE or COMPONENT is converted, build a new + component reference tree. */ + if (base != orig_base || component != orig_component) + return build3 (COMPONENT_REF, TREE_TYPE (component), + base, component, NULL_TREE); + else + return expr; + } + case INDIRECT_REF: + { + tree orig_base = TREE_OPERAND (expr, 0); + tree base = get_non_ssa_expr (orig_base); + if (!base) + return NULL_TREE; + /* If BASE is converted, build a new indirect reference tree. */ + if (base != orig_base) + return build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (base)), base); + else + return expr; + } + case ARRAY_REF: + { + tree array, orig_array = TREE_OPERAND (expr, 0); + tree index, orig_index = TREE_OPERAND (expr, 1); + array = get_non_ssa_expr (orig_array); + if (!array) + return NULL_TREE; + index = get_non_ssa_expr (orig_index); + if (!index) + return NULL_TREE; + /* If either ARRAY or INDEX is converted, build a new array + reference tree. */ + if (array != orig_array || index != orig_index) + return build4 (ARRAY_REF, TREE_TYPE (expr), array, index, + TREE_OPERAND (expr, 2), TREE_OPERAND (expr, 3)); + else + return expr; + } + case SSA_NAME: + { + tree vdecl = SSA_NAME_VAR (expr); + if (DECL_ARTIFICIAL (vdecl) + && !gimple_nop_p (SSA_NAME_DEF_STMT (expr))) + { + gimple def_stmt = SSA_NAME_DEF_STMT (expr); + if (is_gimple_assign (def_stmt) + && (get_gimple_rhs_class (gimple_assign_rhs_code (def_stmt)) + == GIMPLE_SINGLE_RHS)) + vdecl = gimple_assign_rhs1 (def_stmt); + } + return get_non_ssa_expr (vdecl); + } + case INTEGER_CST: + return expr; + default: + /* Return NULL_TREE for any other kind of tree nodes. */ + return NULL_TREE; + } +} + +/* Given the LHS and (real) RHS of a gimple assign statement, STMT, check if + they are the same. If so, print a warning message about self-assignment. */ + +static void +compare_and_warn (gimple stmt, tree lhs, tree rhs) +{ + if (operand_equal_p (lhs, rhs, OEP_PURE_SAME)) + { + location_t location; + location = (gimple_has_location (stmt) + ? gimple_location (stmt) + : (DECL_P (lhs) + ? DECL_SOURCE_LOCATION (lhs) + : input_location)); + /* If LHS contains any tree node not currently supported by + get_non_ssa_expr, simply emit a generic warning without + specifying LHS in the message. */ + lhs = get_non_ssa_expr (lhs); + if (lhs) + warning (0, G_("%H%qE is assigned to itself"), &location, lhs); + else + warning (0, G_("%Hself-assignment detected"), &location); + } +} + +/* Check and warn if STMT is a self-assign statement. */ + +static void +warn_self_assign (gimple stmt) +{ + tree rhs, lhs; + + /* Check assigment statement. */ + if (is_gimple_assign (stmt) + && (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) + == GIMPLE_SINGLE_RHS)) + { + rhs = get_real_ref_rhs (gimple_assign_rhs1 (stmt)); + if (!rhs) + return; + + lhs = gimple_assign_lhs (stmt); + if (TREE_CODE (lhs) == SSA_NAME) + { + lhs = SSA_NAME_VAR (lhs); + if (DECL_ARTIFICIAL (lhs)) + return; + } + + compare_and_warn (stmt, lhs, rhs); + } + /* Check overloaded operator '=' (if enabled). */ + else if (check_operator_eq && is_gimple_call (stmt)) + { + tree fdecl = gimple_call_fndecl (stmt); + if (fdecl && (DECL_NAME (fdecl) == maybe_get_identifier ("operator="))) + { + /* If 'operator=' takes reference operands, the arguments will be + ADDR_EXPR trees. In this case, just remove the address-taken + operator before we compare the lhs and rhs. */ + lhs = gimple_call_arg (stmt, 0); + if (TREE_CODE (lhs) == ADDR_EXPR) + lhs = TREE_OPERAND (lhs, 0); + rhs = gimple_call_arg (stmt, 1); + if (TREE_CODE (rhs) == ADDR_EXPR) + rhs = TREE_OPERAND (rhs, 0); + + compare_and_warn (stmt, lhs, rhs); + } + } +} + +/* Entry point for the self-assignment detection pass. */ + +static unsigned int +execute_warn_self_assign (void) +{ + gimple_stmt_iterator gsi; + basic_block bb; + + FOR_EACH_BB (bb) + { + for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) + warn_self_assign (gsi_stmt (gsi)); + } + + return 0; +} + +/* Pass gate function. Currently always returns true. */ + +static bool +gate_warn_self_assign (void) +{ + return true; +} + +static struct gimple_opt_pass pass_warn_self_assign = +{ + { + GIMPLE_PASS, + "warn_self_assign", /* name */ + gate_warn_self_assign, /* gate */ + execute_warn_self_assign, /* execute */ + NULL, /* sub */ + NULL, /* next */ + 0, /* static_pass_number */ + 0, /* tv_id */ + PROP_ssa, /* properties_required */ + 0, /* properties_provided */ + 0, /* properties_destroyed */ + 0, /* todo_flags_start */ + TODO_dump_func /* todo_flags_finish */ + } +}; + +/* The initialization routine exposed to and called by GCC. The spec of this + function is defined in gcc/gcc-plugin.h. + + PLUGIN_NAME - name of the plugin (useful for error reporting) + ARGC - the size of the ARGV array + ARGV - an array of key-value argument pair + + Returns 0 if initialization finishes successfully. + + Note that this function needs to be named exactly "plugin_init". */ + +int +plugin_init (const char *plugin_name, struct plugin_gcc_version *version, + int argc, struct plugin_argument *argv) +{ + struct plugin_pass pass_info; + bool enabled = true; + int i; + + if (!plugin_default_version_check (version, version)) + return 1; + + /* Self-assign detection should happen after SSA is constructed. */ + pass_info.pass = &pass_warn_self_assign.pass; + pass_info.reference_pass_name = "ssa"; + pass_info.ref_pass_instance_number = 1; + pass_info.pos_op = PASS_POS_INSERT_AFTER; + + /* Process the plugin arguments. This plugin takes the following arguments: + check-operator-eq, no-check-operator-eq, enable, and disable. + By default, the analysis is enabled with 'operator=' checked. */ + for (i = 0; i < argc; ++i) + { + if (!strcmp (argv[i].key, "check-operator-eq")) + { + if (argv[i].value) + warning (0, G_("option '-fplugin-arg-%s-check-operator-eq=%s'" + " ignored (superfluous '=%s')"), + plugin_name, argv[i].value, argv[i].value); + else + check_operator_eq = true; + } + else if (!strcmp (argv[i].key, "no-check-operator-eq")) + { + if (argv[i].value) + warning (0, G_("option '-fplugin-arg-%s-no-check-operator-eq=%s'" + " ignored (superfluous '=%s')"), + plugin_name, argv[i].value, argv[i].value); + else + check_operator_eq = false; + } + else if (!strcmp (argv[i].key, "enable")) + { + if (argv[i].value) + warning (0, G_("option '-fplugin-arg-%s-enable=%s' ignored" + " (superfluous '=%s')"), + plugin_name, argv[i].value, argv[i].value); + else + enabled = true; + } + else if (!strcmp (argv[i].key, "disable")) + { + if (argv[i].value) + warning (0, G_("option '-fplugin-arg-%s-disable=%s' ignored" + " (superfluous '=%s')"), + plugin_name, argv[i].value, argv[i].value); + else + enabled = false; + } + else + warning (0, G_("plugin %qs: unrecognized argument %qs ignored"), + plugin_name, argv[i].key); + } + + /* Register this new pass with GCC if the analysis is enabled. */ + if (enabled) + register_callback (plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, + &pass_info); + + return 0; +} |