From 0c8effa32e9326ca80f3e7cd74635e1dc44b3db5 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Mon, 8 Mar 2021 07:27:57 -0700 Subject: [PATCH] Introduce var_msym_value_operation This adds class var_msym_value_operation, which implements OP_VAR_MSYM_VALUE. A new method is added to class operation in order to support a special case in minsym evaluation. gdb/ChangeLog 2021-03-08 Tom Tromey * expression.h (class operation) : New method. * expop.h (class var_msym_value_operation): New. * eval.c (eval_op_var_msym_value): No longer static. (var_msym_value_operation::evaluate_for_address) (var_msym_value_operation::evaluate_for_sizeof) (var_msym_value_operation::evaluate_for_cast): New methods. * ax-gdb.c (var_msym_value_operation::do_generate_ax): New method. --- gdb/ChangeLog | 11 ++++++++ gdb/ax-gdb.c | 17 ++++++++++++ gdb/eval.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++- gdb/expop.h | 52 ++++++++++++++++++++++++++++++++++++ gdb/expression.h | 4 +++ 5 files changed, 152 insertions(+), 1 deletion(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 1b08ff5b9ec..129a2383da8 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,14 @@ +2021-03-08 Tom Tromey + + * expression.h (class operation) : New method. + * expop.h (class var_msym_value_operation): New. + * eval.c (eval_op_var_msym_value): No longer static. + (var_msym_value_operation::evaluate_for_address) + (var_msym_value_operation::evaluate_for_sizeof) + (var_msym_value_operation::evaluate_for_cast): New methods. + * ax-gdb.c (var_msym_value_operation::do_generate_ax): New + method. + 2021-03-08 Tom Tromey * expop.h (class long_const_operation): New. diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c index 7640b1ba925..60281700703 100644 --- a/gdb/ax-gdb.c +++ b/gdb/ax-gdb.c @@ -2324,6 +2324,23 @@ long_const_operation::do_generate_ax (struct expression *exp, std::get<0> (m_storage)); } +void +var_msym_value_operation::do_generate_ax (struct expression *exp, + struct agent_expr *ax, + struct axs_value *value, + struct type *cast_type) +{ + gen_msym_var_ref (ax, value, std::get<0> (m_storage), + std::get<1> (m_storage)); + + if (value->type->code () == TYPE_CODE_ERROR) + { + if (cast_type == nullptr) + error_unknown_type (std::get<0> (m_storage)->linkage_name ()); + value->type = cast_type; + } +} + } /* This handles the middle-to-right-side of code generation for binary diff --git a/gdb/eval.c b/gdb/eval.c index 452f088a515..85e67f3fb93 100644 --- a/gdb/eval.c +++ b/gdb/eval.c @@ -1221,7 +1221,7 @@ eval_op_var_entry_value (struct type *expect_type, struct expression *exp, /* Helper function that implements the body of OP_VAR_MSYM_VALUE. */ -static struct value * +struct value * eval_op_var_msym_value (struct type *expect_type, struct expression *exp, enum noside noside, bool outermost_p, minimal_symbol *msymbol, struct objfile *objfile) @@ -3301,6 +3301,22 @@ scope_operation::evaluate_for_address (struct expression *exp, return x; } +value * +var_msym_value_operation::evaluate_for_address (struct expression *exp, + enum noside noside) +{ + value *val = evaluate_var_msym_value (noside, + std::get<1> (m_storage), + std::get<0> (m_storage)); + if (noside == EVAL_AVOID_SIDE_EFFECTS) + { + struct type *type = lookup_pointer_type (value_type (val)); + return value_zero (type, not_lval); + } + else + return value_addr (val); +} + } /* Evaluate like `evaluate_subexp' except coercing arrays to pointers. @@ -3501,6 +3517,25 @@ operation::evaluate_for_sizeof (struct expression *exp, enum noside noside) return evaluate_subexp_for_sizeof_base (exp, value_type (val)); } +value * +var_msym_value_operation::evaluate_for_sizeof (struct expression *exp, + enum noside noside) + +{ + minimal_symbol *msymbol = std::get<0> (m_storage); + value *mval = evaluate_var_msym_value (noside, + std::get<1> (m_storage), + msymbol); + + struct type *type = value_type (mval); + if (type->code () == TYPE_CODE_ERROR) + error_unknown_type (msymbol->print_name ()); + + /* FIXME: This should be size_t. */ + struct type *size_type = builtin_type (exp->gdbarch)->builtin_int; + return value_from_longest (size_type, TYPE_LENGTH (type)); +} + } /* Evaluate a subexpression of EXP, at index *POS, and return a value @@ -3558,6 +3593,38 @@ evaluate_subexp_for_cast (expression *exp, int *pos, return value_cast (to_type, val); } +namespace expr +{ + +value * +var_msym_value_operation::evaluate_for_cast (struct type *to_type, + struct expression *exp, + enum noside noside) +{ + if (noside == EVAL_AVOID_SIDE_EFFECTS) + return value_zero (to_type, not_lval); + + value *val = evaluate_var_msym_value (noside, + std::get<1> (m_storage), + std::get<0> (m_storage)); + + if (noside == EVAL_SKIP) + return eval_skip_value (exp); + + val = value_cast (to_type, val); + + /* Don't allow e.g. '&(int)var_with_no_debug_info'. */ + if (VALUE_LVAL (val) == lval_memory) + { + if (value_lazy (val)) + value_fetch_lazy (val); + VALUE_LVAL (val) = not_lval; + } + return val; +} + +} + /* Parse a type expression in the string [P..P+LENGTH). */ struct type * diff --git a/gdb/expop.h b/gdb/expop.h index ed883be6fc4..345cac29976 100644 --- a/gdb/expop.h +++ b/gdb/expop.h @@ -45,6 +45,12 @@ extern struct value *eval_op_scope (struct type *expect_type, struct expression *exp, enum noside noside, struct type *type, const char *string); +extern struct value *eval_op_var_msym_value (struct type *expect_type, + struct expression *exp, + enum noside noside, + bool outermost_p, + minimal_symbol *msymbol, + struct objfile *objfile); namespace expr { @@ -481,6 +487,52 @@ protected: override; }; +class var_msym_value_operation + : public maybe_constant_operation +{ +public: + + using maybe_constant_operation::maybe_constant_operation; + + value *evaluate (struct type *expect_type, + struct expression *exp, + enum noside noside) override + { + return eval_op_var_msym_value (expect_type, exp, noside, m_outermost, + std::get<0> (m_storage), + std::get<1> (m_storage)); + } + + value *evaluate_for_sizeof (struct expression *exp, enum noside noside) + override; + + value *evaluate_for_address (struct expression *exp, enum noside noside) + override; + + value *evaluate_for_cast (struct type *expect_type, + struct expression *exp, + enum noside noside) override; + + enum exp_opcode opcode () const override + { return OP_VAR_MSYM_VALUE; } + + void set_outermost () override + { + m_outermost = true; + } + +protected: + + /* True if this is the outermost operation in the expression. */ + bool m_outermost = false; + + void do_generate_ax (struct expression *exp, + struct agent_expr *ax, + struct axs_value *value, + struct type *cast_type) + override; +}; + } /* namespace expr */ #endif /* EXPOP_H */ diff --git a/gdb/expression.h b/gdb/expression.h index 24a0eb37722..4d75058dc22 100644 --- a/gdb/expression.h +++ b/gdb/expression.h @@ -165,6 +165,10 @@ public: /* Print this operation to STREAM. */ virtual void dump (struct ui_file *stream, int depth) const = 0; + /* Call to indicate that this is the outermost operation in the + expression. This should almost never be overridden. */ + virtual void set_outermost () { } + protected: /* Called by generate_ax to do the work for this particular -- 2.30.2