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Diffstat (limited to 'gcc/rust/backend/rust-tree.cc')
| -rw-r--r-- | gcc/rust/backend/rust-tree.cc | 659 |
1 files changed, 659 insertions, 0 deletions
diff --git a/gcc/rust/backend/rust-tree.cc b/gcc/rust/backend/rust-tree.cc new file mode 100644 index 0000000..8e39408 --- /dev/null +++ b/gcc/rust/backend/rust-tree.cc @@ -0,0 +1,659 @@ +// Copyright (C) 2020-2022 Free Software Foundation, Inc. + +// This file is part of GCC. + +// GCC is free software; you can redistribute it and/or modify it under +// the terms of the GNU General Public License as published by the Free +// Software Foundation; either version 3, or (at your option) any later +// version. + +// GCC is distributed in the hope that it will be useful, but WITHOUT ANY +// WARRANTY; without even the implied warranty of MERCHANTABILITY or +// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +// for more details. + +// You should have received a copy of the GNU General Public License +// along with GCC; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include "rust-tree.h" +#include "stringpool.h" +#include "attribs.h" +#include "escaped_string.h" + +namespace Rust { + +void +mark_exp_read (tree exp) +{ + if (exp == NULL) + return; + + switch (TREE_CODE (exp)) + { + case VAR_DECL: + gcc_fallthrough (); + case PARM_DECL: + DECL_READ_P (exp) = 1; + break; + case ARRAY_REF: + case COMPONENT_REF: + case MODIFY_EXPR: + case REALPART_EXPR: + case IMAGPART_EXPR: + CASE_CONVERT: + case ADDR_EXPR: + case INDIRECT_REF: + case FLOAT_EXPR: + case NON_DEPENDENT_EXPR: + case VIEW_CONVERT_EXPR: + mark_exp_read (TREE_OPERAND (exp, 0)); + break; + case COMPOUND_EXPR: + mark_exp_read (TREE_OPERAND (exp, 1)); + break; + case COND_EXPR: + if (TREE_OPERAND (exp, 1)) + mark_exp_read (TREE_OPERAND (exp, 1)); + if (TREE_OPERAND (exp, 2)) + mark_exp_read (TREE_OPERAND (exp, 2)); + break; + default: + break; + } +} + +tree +convert_from_reference (tree val) +{ + if (TREE_TYPE (val) && TYPE_REF_P (TREE_TYPE (val))) + { + tree t = TREE_TYPE (TREE_TYPE (val)); + tree ref = build1 (INDIRECT_REF, t, val); + + mark_exp_read (val); + + TREE_SIDE_EFFECTS (ref) + = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val)); + val = ref; + } + + return val; +} + +tree +mark_use (tree expr, bool rvalue_p, bool read_p, + location_t loc /* = UNKNOWN_LOCATION */, + bool reject_builtin /* = true */) +{ +#define RECUR(t) mark_use ((t), rvalue_p, read_p, loc, reject_builtin) + + if (expr == NULL_TREE || error_operand_p (expr)) + return expr; + + if (reject_builtin) + return error_mark_node; + + if (read_p) + mark_exp_read (expr); + + bool recurse_op[3] = {false, false, false}; + switch (TREE_CODE (expr)) + { + case COMPONENT_REF: + case NON_DEPENDENT_EXPR: + recurse_op[0] = true; + break; + case COMPOUND_EXPR: + recurse_op[1] = true; + break; + case COND_EXPR: + recurse_op[2] = true; + if (TREE_OPERAND (expr, 1)) + recurse_op[1] = true; + break; + case INDIRECT_REF: + if (REFERENCE_REF_P (expr)) + { + /* Try to look through the reference. */ + tree ref = TREE_OPERAND (expr, 0); + tree r = mark_rvalue_use (ref, loc, reject_builtin); + if (r != ref) + expr = convert_from_reference (r); + } + break; + + case VIEW_CONVERT_EXPR: + if (location_wrapper_p (expr)) + { + loc = EXPR_LOCATION (expr); + tree op = TREE_OPERAND (expr, 0); + tree nop = RECUR (op); + if (nop == error_mark_node) + return error_mark_node; + else if (op == nop) + /* No change. */; + else if (DECL_P (nop) || CONSTANT_CLASS_P (nop)) + { + /* Reuse the location wrapper. */ + TREE_OPERAND (expr, 0) = nop; + /* If we're replacing a DECL with a constant, we also need to + change the TREE_CODE of the location wrapper. */ + if (rvalue_p) + TREE_SET_CODE (expr, NON_LVALUE_EXPR); + } + else + { + /* Drop the location wrapper. */ + expr = nop; + protected_set_expr_location (expr, loc); + } + return expr; + } + gcc_fallthrough (); + CASE_CONVERT: + recurse_op[0] = true; + break; + + default: + break; + } + + for (int i = 0; i < 3; ++i) + if (recurse_op[i]) + { + tree op = TREE_OPERAND (expr, i); + op = RECUR (op); + if (op == error_mark_node) + return error_mark_node; + TREE_OPERAND (expr, i) = op; + } + + return expr; +#undef RECUR +} + +tree +mark_rvalue_use (tree e, location_t loc /* = UNKNOWN_LOCATION */, + bool reject_builtin /* = true */) +{ + return mark_use (e, true, true, loc, reject_builtin); +} + +tree +mark_lvalue_use (tree expr) +{ + return mark_use (expr, false, true, input_location, false); +} + +tree +mark_lvalue_use_nonread (tree expr) +{ + return mark_use (expr, false, false, input_location, false); +} + +tree +mark_discarded_use (tree expr) +{ + if (expr == NULL_TREE) + return expr; + + STRIP_ANY_LOCATION_WRAPPER (expr); + + switch (TREE_CODE (expr)) + { + case COND_EXPR: + TREE_OPERAND (expr, 2) = mark_discarded_use (TREE_OPERAND (expr, 2)); + gcc_fallthrough (); + case COMPOUND_EXPR: + TREE_OPERAND (expr, 1) = mark_discarded_use (TREE_OPERAND (expr, 1)); + return expr; + + case COMPONENT_REF: + case ARRAY_REF: + case INDIRECT_REF: + case MEMBER_REF: + break; + default: + if (DECL_P (expr)) + break; + else + return expr; + } + + return mark_use (expr, true, true, input_location, false); +} + +tree +convert_to_void (tree expr, impl_conv_void implicit) +{ + location_t loc = expr_loc_or_input_loc (expr); + if (expr == error_mark_node || TREE_TYPE (expr) == error_mark_node) + return error_mark_node; + + expr = mark_discarded_use (expr); + if (implicit == ICV_CAST) + /* An explicit cast to void avoids all -Wunused-but-set* warnings. */ + mark_exp_read (expr); + + if (!TREE_TYPE (expr)) + return expr; + + if (VOID_TYPE_P (TREE_TYPE (expr))) + return expr; + switch (TREE_CODE (expr)) + { + case COND_EXPR: { + /* The two parts of a cond expr might be separate lvalues. */ + tree op1 = TREE_OPERAND (expr, 1); + tree op2 = TREE_OPERAND (expr, 2); + bool side_effects + = ((op1 && TREE_SIDE_EFFECTS (op1)) || TREE_SIDE_EFFECTS (op2)); + tree new_op1, new_op2; + new_op1 = NULL_TREE; + if (implicit != ICV_CAST && !side_effects) + { + if (op1) + new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND); + new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND); + } + else + { + if (op1) + new_op1 = convert_to_void (op1, ICV_CAST); + new_op2 = convert_to_void (op2, ICV_CAST); + } + + expr = build3_loc (loc, COND_EXPR, TREE_TYPE (new_op2), + TREE_OPERAND (expr, 0), new_op1, new_op2); + break; + } + + case COMPOUND_EXPR: { + /* The second part of a compound expr contains the value. */ + tree op1 = TREE_OPERAND (expr, 1); + tree new_op1; + if (implicit != ICV_CAST + && !warning_suppressed_p (expr /* What warning? */)) + new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA); + else + new_op1 = convert_to_void (op1, ICV_CAST); + + if (new_op1 != op1) + { + tree t = build2_loc (loc, COMPOUND_EXPR, TREE_TYPE (new_op1), + TREE_OPERAND (expr, 0), new_op1); + expr = t; + } + + break; + } + + case NON_LVALUE_EXPR: + case NOP_EXPR: + /* These have already decayed to rvalue. */ + break; + + case CALL_EXPR: + maybe_warn_nodiscard (expr, implicit); + break; + + case INDIRECT_REF: { + tree type = TREE_TYPE (expr); + int is_reference = TYPE_REF_P (TREE_TYPE (TREE_OPERAND (expr, 0))); + int is_volatile = TYPE_VOLATILE (type); + int is_complete = COMPLETE_TYPE_P (type); + + /* Can't load the value if we don't know the type. */ + if (is_volatile && !is_complete) + { + switch (implicit) + { + case ICV_CAST: + warning_at (loc, 0, + "conversion to void will not access " + "object of incomplete type %qT", + type); + break; + case ICV_SECOND_OF_COND: + warning_at (loc, 0, + "indirection will not access object of " + "incomplete type %qT in second operand " + "of conditional expression", + type); + break; + case ICV_THIRD_OF_COND: + warning_at (loc, 0, + "indirection will not access object of " + "incomplete type %qT in third operand " + "of conditional expression", + type); + break; + case ICV_RIGHT_OF_COMMA: + warning_at (loc, 0, + "indirection will not access object of " + "incomplete type %qT in right operand of " + "comma operator", + type); + break; + case ICV_LEFT_OF_COMMA: + warning_at (loc, 0, + "indirection will not access object of " + "incomplete type %qT in left operand of " + "comma operator", + type); + break; + case ICV_STATEMENT: + warning_at (loc, 0, + "indirection will not access object of " + "incomplete type %qT in statement", + type); + break; + case ICV_THIRD_IN_FOR: + warning_at (loc, 0, + "indirection will not access object of " + "incomplete type %qT in for increment " + "expression", + type); + break; + default: + gcc_unreachable (); + } + } + /* Don't load the value if this is an implicit dereference, or if + the type needs to be handled by ctors/dtors. */ + else if (is_volatile && is_reference) + { + switch (implicit) + { + case ICV_CAST: + warning_at (loc, 0, + "conversion to void will not access " + "object of type %qT", + type); + break; + case ICV_SECOND_OF_COND: + warning_at (loc, 0, + "implicit dereference will not access " + "object of type %qT in second operand of " + "conditional expression", + type); + break; + case ICV_THIRD_OF_COND: + warning_at (loc, 0, + "implicit dereference will not access " + "object of type %qT in third operand of " + "conditional expression", + type); + break; + case ICV_RIGHT_OF_COMMA: + warning_at (loc, 0, + "implicit dereference will not access " + "object of type %qT in right operand of " + "comma operator", + type); + break; + case ICV_LEFT_OF_COMMA: + warning_at (loc, 0, + "implicit dereference will not access " + "object of type %qT in left operand of comma " + "operator", + type); + break; + case ICV_STATEMENT: + warning_at (loc, 0, + "implicit dereference will not access " + "object of type %qT in statement", + type); + break; + case ICV_THIRD_IN_FOR: + warning_at (loc, 0, + "implicit dereference will not access " + "object of type %qT in for increment expression", + type); + break; + default: + gcc_unreachable (); + } + } + else if (is_volatile && TREE_ADDRESSABLE (type)) + { + switch (implicit) + { + case ICV_CAST: + warning_at (loc, 0, + "conversion to void will not access " + "object of non-trivially-copyable type %qT", + type); + break; + case ICV_SECOND_OF_COND: + warning_at (loc, 0, + "indirection will not access object of " + "non-trivially-copyable type %qT in second " + "operand of conditional expression", + type); + break; + case ICV_THIRD_OF_COND: + warning_at (loc, 0, + "indirection will not access object of " + "non-trivially-copyable type %qT in third " + "operand of conditional expression", + type); + break; + case ICV_RIGHT_OF_COMMA: + warning_at (loc, 0, + "indirection will not access object of " + "non-trivially-copyable type %qT in right " + "operand of comma operator", + type); + break; + case ICV_LEFT_OF_COMMA: + warning_at (loc, 0, + "indirection will not access object of " + "non-trivially-copyable type %qT in left " + "operand of comma operator", + type); + break; + case ICV_STATEMENT: + warning_at (loc, 0, + "indirection will not access object of " + "non-trivially-copyable type %qT in statement", + type); + break; + case ICV_THIRD_IN_FOR: + warning_at (loc, 0, + "indirection will not access object of " + "non-trivially-copyable type %qT in for " + "increment expression", + type); + break; + default: + gcc_unreachable (); + } + } + if (is_reference || !is_volatile || !is_complete + || TREE_ADDRESSABLE (type)) + { + /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF + operation is stripped off. Note that we don't warn about + - an expression with TREE_NO_WARNING set. (For an example of + such expressions, see build_over_call in call.cc.) + - automatic dereferencing of references, since the user cannot + control it. (See also warn_if_unused_value() in c-common.cc.) + */ + if (warn_unused_value && implicit != ICV_CAST + && !warning_suppressed_p (expr, OPT_Wunused_value) + && !is_reference) + warning_at (loc, OPT_Wunused_value, "value computed is not used"); + expr = TREE_OPERAND (expr, 0); + if (TREE_CODE (expr) == CALL_EXPR) + maybe_warn_nodiscard (expr, implicit); + } + + break; + } + + case VAR_DECL: { + /* External variables might be incomplete. */ + tree type = TREE_TYPE (expr); + int is_complete = COMPLETE_TYPE_P (type); + + if (TYPE_VOLATILE (type) && !is_complete) + switch (implicit) + { + case ICV_CAST: + warning_at (loc, 0, + "conversion to void will not access " + "object %qE of incomplete type %qT", + expr, type); + break; + case ICV_SECOND_OF_COND: + warning_at (loc, 0, + "variable %qE of incomplete type %qT will " + "not be accessed in second operand of " + "conditional expression", + expr, type); + break; + case ICV_THIRD_OF_COND: + warning_at (loc, 0, + "variable %qE of incomplete type %qT will " + "not be accessed in third operand of " + "conditional expression", + expr, type); + break; + case ICV_RIGHT_OF_COMMA: + warning_at (loc, 0, + "variable %qE of incomplete type %qT will " + "not be accessed in right operand of comma operator", + expr, type); + break; + case ICV_LEFT_OF_COMMA: + warning_at (loc, 0, + "variable %qE of incomplete type %qT will " + "not be accessed in left operand of comma operator", + expr, type); + break; + case ICV_STATEMENT: + warning_at (loc, 0, + "variable %qE of incomplete type %qT will " + "not be accessed in statement", + expr, type); + break; + case ICV_THIRD_IN_FOR: + warning_at (loc, 0, + "variable %qE of incomplete type %qT will " + "not be accessed in for increment expression", + expr, type); + break; + default: + gcc_unreachable (); + } + + break; + } + + default:; + } + + if (!TREE_SIDE_EFFECTS (expr)) + expr = void_node; + + return expr; +} + +void +maybe_warn_nodiscard (tree expr, impl_conv_void implicit) +{ + tree call = expr; + if (TREE_CODE (expr) == TARGET_EXPR) + call = TARGET_EXPR_INITIAL (expr); + + location_t loc = expr_loc_or_input_loc (call); + tree callee = CALL_EXPR_FN (call); + if (!callee) + return; + + tree type = TREE_TYPE (callee); + if (INDIRECT_TYPE_P (type)) + type = TREE_TYPE (type); + + tree rettype = TREE_TYPE (type); + tree fn = get_fndecl_from_callee (callee); + tree attr; + if (implicit != ICV_CAST && fn + && (attr = lookup_attribute ("nodiscard", DECL_ATTRIBUTES (fn)))) + { + escaped_string msg; + tree args = TREE_VALUE (attr); + if (args) + msg.escape (TREE_STRING_POINTER (TREE_VALUE (args))); + const char *format + = (msg ? G_ ("ignoring return value of %qD, that must be used: %<%s%>") + : G_ ("ignoring return value of %qD, that must be used")); + const char *raw_msg = msg ? (const char *) msg : ""; + auto_diagnostic_group d; + if (warning_at (loc, OPT_Wunused_result, format, fn, raw_msg)) + inform (DECL_SOURCE_LOCATION (fn), "declared here"); + } + else if (implicit != ICV_CAST + && (attr + = lookup_attribute ("nodiscard", TYPE_ATTRIBUTES (rettype)))) + { + escaped_string msg; + tree args = TREE_VALUE (attr); + if (args) + msg.escape (TREE_STRING_POINTER (TREE_VALUE (args))); + const char *format + = (msg ? G_ ( + "ignoring returned value of type %qT, that must be used: %<%s%>") + : G_ ("ignoring returned value of type %qT, that must be used")); + const char *raw_msg = msg ? (const char *) msg : ""; + auto_diagnostic_group d; + if (warning_at (loc, OPT_Wunused_result, format, rettype, raw_msg)) + { + if (fn) + inform (DECL_SOURCE_LOCATION (fn), "in call to %qD, declared here", + fn); + inform (DECL_SOURCE_LOCATION (TYPE_NAME (rettype)), + "%qT declared here", rettype); + } + } +} + +location_t +expr_loc_or_loc (const_tree t, location_t or_loc) +{ + location_t loc = EXPR_LOCATION (t); + if (loc == UNKNOWN_LOCATION) + loc = or_loc; + return loc; +} + +location_t +expr_loc_or_input_loc (const_tree t) +{ + return expr_loc_or_loc (t, input_location); +} + +// FN is the callee of a CALL_EXPR or AGGR_INIT_EXPR; return the FUNCTION_DECL +// if we can. +tree +get_fndecl_from_callee (tree fn) +{ + if (fn == NULL_TREE) + return fn; + if (TREE_CODE (fn) == FUNCTION_DECL) + return fn; + tree type = TREE_TYPE (fn); + if (type == NULL_TREE || !INDIRECT_TYPE_P (type)) + return NULL_TREE; + + STRIP_NOPS (fn); + if (TREE_CODE (fn) == ADDR_EXPR || TREE_CODE (fn) == FDESC_EXPR) + fn = TREE_OPERAND (fn, 0); + if (TREE_CODE (fn) == FUNCTION_DECL) + return fn; + return NULL_TREE; +} + +} // namespace Rust |