From: Alejandro Piñeiro Date: Thu, 25 Feb 2016 10:11:54 +0000 (+0100) Subject: glsl: add is_lhs bool on ast_expression X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8568d02498d12ebde6a6245056eebfbfe18aaf8f;p=mesa.git glsl: add is_lhs bool on ast_expression Useful to know if a expression is the recipient of an assignment or not, that would be used to (for example) raise warnings of "use of uninitialized variable" without getting a false positive when assigning first a variable. By default the value is false, and it is assigned to true on the following cases: * The lhs assignments subexpression * At ast_array_index, on the array itself. * While handling the method on an array, to avoid the warning calling array.length * When computed the cached test expression at test_to_hir, to avoid a duplicate warning on the test expression of a switch. set_is_lhs setter is added, because in some cases (like ast_field_selection) the value need to be propagated on the expression tree. To avoid doing the propatagion if not needed, it skips if no primary_expression.identifier is available. v2: use a new bool on ast_expression, instead of a new parameter on ast_expression::hir (Timothy Arceri) v3: fix style and some typos on comments, initialize is_lhs default value on constructor, to avoid a c++11 feature (Ian Romanick) v4: some tweaks on comments (Timothy Arceri) Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94129 Reviewed-by: Timothy Arceri --- diff --git a/src/compiler/glsl/ast.h b/src/compiler/glsl/ast.h index 727aa432631..9f46340e6e2 100644 --- a/src/compiler/glsl/ast.h +++ b/src/compiler/glsl/ast.h @@ -214,6 +214,7 @@ public: subexpressions[2] = NULL; primary_expression.identifier = identifier; this->non_lvalue_description = NULL; + this->is_lhs = false; } static const char *operator_string(enum ast_operators op); @@ -263,6 +264,11 @@ public: * This pointer may be \c NULL. */ const char *non_lvalue_description; + + void set_is_lhs(bool new_value); + +private: + bool is_lhs; }; class ast_expression_bin : public ast_expression { diff --git a/src/compiler/glsl/ast_function.cpp b/src/compiler/glsl/ast_function.cpp index 1a440203cfc..db68d5dfa48 100644 --- a/src/compiler/glsl/ast_function.cpp +++ b/src/compiler/glsl/ast_function.cpp @@ -1727,6 +1727,10 @@ ast_function_expression::handle_method(exec_list *instructions, const char *method; method = field->primary_expression.identifier; + /* This would prevent to raise "uninitialized variable" warnings when + * calling array.length. + */ + field->subexpressions[0]->set_is_lhs(true); op = field->subexpressions[0]->hir(instructions, state); if (strcmp(method, "length") == 0) { if (!this->expressions.is_empty()) { diff --git a/src/compiler/glsl/ast_to_hir.cpp b/src/compiler/glsl/ast_to_hir.cpp index 35def8e3ae0..e162203c1c8 100644 --- a/src/compiler/glsl/ast_to_hir.cpp +++ b/src/compiler/glsl/ast_to_hir.cpp @@ -1248,6 +1248,24 @@ ast_expression::hir_no_rvalue(exec_list *instructions, do_hir(instructions, state, false); } +void +ast_expression::set_is_lhs(bool new_value) +{ + /* is_lhs is tracked only to print "variable used uninitialized" warnings, + * if we lack a identifier we can just skip it. + */ + if (this->primary_expression.identifier == NULL) + return; + + this->is_lhs = new_value; + + /* We need to go through the subexpressions tree to cover cases like + * ast_field_selection + */ + if (this->subexpressions[0] != NULL) + this->subexpressions[0]->set_is_lhs(new_value); +} + ir_rvalue * ast_expression::do_hir(exec_list *instructions, struct _mesa_glsl_parse_state *state, @@ -1323,6 +1341,7 @@ ast_expression::do_hir(exec_list *instructions, break; case ast_assign: { + this->subexpressions[0]->set_is_lhs(true); op[0] = this->subexpressions[0]->hir(instructions, state); op[1] = this->subexpressions[1]->hir(instructions, state); @@ -1592,6 +1611,7 @@ ast_expression::do_hir(exec_list *instructions, case ast_div_assign: case ast_add_assign: case ast_sub_assign: { + this->subexpressions[0]->set_is_lhs(true); op[0] = this->subexpressions[0]->hir(instructions, state); op[1] = this->subexpressions[1]->hir(instructions, state); @@ -1618,6 +1638,7 @@ ast_expression::do_hir(exec_list *instructions, } case ast_mod_assign: { + this->subexpressions[0]->set_is_lhs(true); op[0] = this->subexpressions[0]->hir(instructions, state); op[1] = this->subexpressions[1]->hir(instructions, state); @@ -1640,6 +1661,7 @@ ast_expression::do_hir(exec_list *instructions, case ast_ls_assign: case ast_rs_assign: { + this->subexpressions[0]->set_is_lhs(true); op[0] = this->subexpressions[0]->hir(instructions, state); op[1] = this->subexpressions[1]->hir(instructions, state); type = shift_result_type(op[0]->type, op[1]->type, this->oper, state, @@ -1658,6 +1680,7 @@ ast_expression::do_hir(exec_list *instructions, case ast_and_assign: case ast_xor_assign: case ast_or_assign: { + this->subexpressions[0]->set_is_lhs(true); op[0] = this->subexpressions[0]->hir(instructions, state); op[1] = this->subexpressions[1]->hir(instructions, state); type = bit_logic_result_type(op[0], op[1], this->oper, state, &loc); @@ -1839,6 +1862,11 @@ ast_expression::do_hir(exec_list *instructions, case ast_array_index: { YYLTYPE index_loc = subexpressions[1]->get_location(); + /* Getting if an array is being used uninitialized is beyond what we get + * from ir_value.data.assigned. Setting is_lhs as true would force to + * not raise a uninitialized warning when using an array + */ + subexpressions[0]->set_is_lhs(true); op[0] = subexpressions[0]->hir(instructions, state); op[1] = subexpressions[1]->hir(instructions, state); @@ -5746,6 +5774,11 @@ ast_switch_statement::test_to_hir(exec_list *instructions, { void *ctx = state; + /* set to true to avoid a duplicate "use of uninitialized variable" warning + * on the switch test case. The first one would be already raised when + * getting the test_expression at ast_switch_statement::hir + */ + test_expression->set_is_lhs(true); /* Cache value of test expression. */ ir_rvalue *const test_val = test_expression->hir(instructions, diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp index 1d9bfd6aaba..ea9639b728d 100644 --- a/src/compiler/glsl/glsl_parser_extras.cpp +++ b/src/compiler/glsl/glsl_parser_extras.cpp @@ -1206,6 +1206,7 @@ ast_expression::ast_expression(int oper, this->subexpressions[1] = ex1; this->subexpressions[2] = ex2; this->non_lvalue_description = NULL; + this->is_lhs = false; }