/* * Copyright © 2010 Intel Corporation * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. */ /** * \file ir_constant_expression.cpp * Evaluate and process constant valued expressions * * In GLSL, constant valued expressions are used in several places. These * must be processed and evaluated very early in the compilation process. * * * Sizes of arrays * * Initializers for uniforms * * Initializers for \c const variables */ #include #include "util/rounding.h" /* for _mesa_roundeven */ #include "util/half_float.h" #include "ir.h" #include "compiler/glsl_types.h" #include "util/hash_table.h" #include "util/u_math.h" static float dot_f(ir_constant *op0, ir_constant *op1) { assert(op0->type->is_float() && op1->type->is_float()); float result = 0; for (unsigned c = 0; c < op0->type->components(); c++) result += op0->value.f[c] * op1->value.f[c]; return result; } static double dot_d(ir_constant *op0, ir_constant *op1) { assert(op0->type->is_double() && op1->type->is_double()); double result = 0; for (unsigned c = 0; c < op0->type->components(); c++) result += op0->value.d[c] * op1->value.d[c]; return result; } /* This method is the only one supported by gcc. Unions in particular * are iffy, and read-through-converted-pointer is killed by strict * aliasing. OTOH, the compiler sees through the memcpy, so the * resulting asm is reasonable. */ static float bitcast_u2f(unsigned int u) { static_assert(sizeof(float) == sizeof(unsigned int), "float and unsigned int size mismatch"); float f; memcpy(&f, &u, sizeof(f)); return f; } static unsigned int bitcast_f2u(float f) { static_assert(sizeof(float) == sizeof(unsigned int), "float and unsigned int size mismatch"); unsigned int u; memcpy(&u, &f, sizeof(f)); return u; } static double bitcast_u642d(uint64_t u) { static_assert(sizeof(double) == sizeof(uint64_t), "double and uint64_t size mismatch"); double d; memcpy(&d, &u, sizeof(d)); return d; } static double bitcast_i642d(int64_t i) { static_assert(sizeof(double) == sizeof(int64_t), "double and int64_t size mismatch"); double d; memcpy(&d, &i, sizeof(d)); return d; } static uint64_t bitcast_d2u64(double d) { static_assert(sizeof(double) == sizeof(uint64_t), "double and uint64_t size mismatch"); uint64_t u; memcpy(&u, &d, sizeof(d)); return u; } static int64_t bitcast_d2i64(double d) { static_assert(sizeof(double) == sizeof(int64_t), "double and int64_t size mismatch"); int64_t i; memcpy(&i, &d, sizeof(d)); return i; } /** * Evaluate one component of a floating-point 4x8 unpacking function. */ typedef uint8_t (*pack_1x8_func_t)(float); /** * Evaluate one component of a floating-point 2x16 unpacking function. */ typedef uint16_t (*pack_1x16_func_t)(float); /** * Evaluate one component of a floating-point 4x8 unpacking function. */ typedef float (*unpack_1x8_func_t)(uint8_t); /** * Evaluate one component of a floating-point 2x16 unpacking function. */ typedef float (*unpack_1x16_func_t)(uint16_t); /** * Evaluate a 2x16 floating-point packing function. */ static uint32_t pack_2x16(pack_1x16_func_t pack_1x16, float x, float y) { /* From section 8.4 of the GLSL ES 3.00 spec: * * packSnorm2x16 * ------------- * The first component of the vector will be written to the least * significant bits of the output; the last component will be written to * the most significant bits. * * The specifications for the other packing functions contain similar * language. */ uint32_t u = 0; u |= ((uint32_t) pack_1x16(x) << 0); u |= ((uint32_t) pack_1x16(y) << 16); return u; } /** * Evaluate a 4x8 floating-point packing function. */ static uint32_t pack_4x8(pack_1x8_func_t pack_1x8, float x, float y, float z, float w) { /* From section 8.4 of the GLSL 4.30 spec: * * packSnorm4x8 * ------------ * The first component of the vector will be written to the least * significant bits of the output; the last component will be written to * the most significant bits. * * The specifications for the other packing functions contain similar * language. */ uint32_t u = 0; u |= ((uint32_t) pack_1x8(x) << 0); u |= ((uint32_t) pack_1x8(y) << 8); u |= ((uint32_t) pack_1x8(z) << 16); u |= ((uint32_t) pack_1x8(w) << 24); return u; } /** * Evaluate a 2x16 floating-point unpacking function. */ static void unpack_2x16(unpack_1x16_func_t unpack_1x16, uint32_t u, float *x, float *y) { /* From section 8.4 of the GLSL ES 3.00 spec: * * unpackSnorm2x16 * --------------- * The first component of the returned vector will be extracted from * the least significant bits of the input; the last component will be * extracted from the most significant bits. * * The specifications for the other unpacking functions contain similar * language. */ *x = unpack_1x16((uint16_t) (u & 0xffff)); *y = unpack_1x16((uint16_t) (u >> 16)); } /** * Evaluate a 4x8 floating-point unpacking function. */ static void unpack_4x8(unpack_1x8_func_t unpack_1x8, uint32_t u, float *x, float *y, float *z, float *w) { /* From section 8.4 of the GLSL 4.30 spec: * * unpackSnorm4x8 * -------------- * The first component of the returned vector will be extracted from * the least significant bits of the input; the last component will be * extracted from the most significant bits. * * The specifications for the other unpacking functions contain similar * language. */ *x = unpack_1x8((uint8_t) (u & 0xff)); *y = unpack_1x8((uint8_t) (u >> 8)); *z = unpack_1x8((uint8_t) (u >> 16)); *w = unpack_1x8((uint8_t) (u >> 24)); } /** * Evaluate one component of packSnorm4x8. */ static uint8_t pack_snorm_1x8(float x) { /* From section 8.4 of the GLSL 4.30 spec: * * packSnorm4x8 * ------------ * The conversion for component c of v to fixed point is done as * follows: * * packSnorm4x8: round(clamp(c, -1, +1) * 127.0) */ return (uint8_t) _mesa_lroundevenf(CLAMP(x, -1.0f, +1.0f) * 127.0f); } /** * Evaluate one component of packSnorm2x16. */ static uint16_t pack_snorm_1x16(float x) { /* From section 8.4 of the GLSL ES 3.00 spec: * * packSnorm2x16 * ------------- * The conversion for component c of v to fixed point is done as * follows: * * packSnorm2x16: round(clamp(c, -1, +1) * 32767.0) */ return (uint16_t) _mesa_lroundevenf(CLAMP(x, -1.0f, +1.0f) * 32767.0f); } /** * Evaluate one component of unpackSnorm4x8. */ static float unpack_snorm_1x8(uint8_t u) { /* From section 8.4 of the GLSL 4.30 spec: * * unpackSnorm4x8 * -------------- * The conversion for unpacked fixed-point value f to floating point is * done as follows: * * unpackSnorm4x8: clamp(f / 127.0, -1, +1) */ return CLAMP((int8_t) u / 127.0f, -1.0f, +1.0f); } /** * Evaluate one component of unpackSnorm2x16. */ static float unpack_snorm_1x16(uint16_t u) { /* From section 8.4 of the GLSL ES 3.00 spec: * * unpackSnorm2x16 * --------------- * The conversion for unpacked fixed-point value f to floating point is * done as follows: * * unpackSnorm2x16: clamp(f / 32767.0, -1, +1) */ return CLAMP((int16_t) u / 32767.0f, -1.0f, +1.0f); } /** * Evaluate one component packUnorm4x8. */ static uint8_t pack_unorm_1x8(float x) { /* From section 8.4 of the GLSL 4.30 spec: * * packUnorm4x8 * ------------ * The conversion for component c of v to fixed point is done as * follows: * * packUnorm4x8: round(clamp(c, 0, +1) * 255.0) */ return (uint8_t) (int) _mesa_roundevenf(SATURATE(x) * 255.0f); } /** * Evaluate one component packUnorm2x16. */ static uint16_t pack_unorm_1x16(float x) { /* From section 8.4 of the GLSL ES 3.00 spec: * * packUnorm2x16 * ------------- * The conversion for component c of v to fixed point is done as * follows: * * packUnorm2x16: round(clamp(c, 0, +1) * 65535.0) */ return (uint16_t) (int) _mesa_roundevenf(SATURATE(x) * 65535.0f); } /** * Evaluate one component of unpackUnorm4x8. */ static float unpack_unorm_1x8(uint8_t u) { /* From section 8.4 of the GLSL 4.30 spec: * * unpackUnorm4x8 * -------------- * The conversion for unpacked fixed-point value f to floating point is * done as follows: * * unpackUnorm4x8: f / 255.0 */ return (float) u / 255.0f; } /** * Evaluate one component of unpackUnorm2x16. */ static float unpack_unorm_1x16(uint16_t u) { /* From section 8.4 of the GLSL ES 3.00 spec: * * unpackUnorm2x16 * --------------- * The conversion for unpacked fixed-point value f to floating point is * done as follows: * * unpackUnorm2x16: f / 65535.0 */ return (float) u / 65535.0f; } /** * Evaluate one component of packHalf2x16. */ static uint16_t pack_half_1x16(float x) { return _mesa_float_to_half(x); } /** * Evaluate one component of unpackHalf2x16. */ static float unpack_half_1x16(uint16_t u) { return _mesa_half_to_float(u); } static int32_t iadd_saturate(int32_t a, int32_t b) { return CLAMP(int64_t(a) + int64_t(b), INT32_MIN, INT32_MAX); } static int64_t iadd64_saturate(int64_t a, int64_t b) { if (a < 0 && b < INT64_MIN - a) return INT64_MIN; if (a > 0 && b > INT64_MAX - a) return INT64_MAX; return a + b; } static int32_t isub_saturate(int32_t a, int32_t b) { return CLAMP(int64_t(a) - int64_t(b), INT32_MIN, INT32_MAX); } static int64_t isub64_saturate(int64_t a, int64_t b) { if (b > 0 && a < INT64_MIN + b) return INT64_MIN; if (b < 0 && a > INT64_MAX + b) return INT64_MAX; return a - b; } static uint64_t pack_2x32(uint32_t a, uint32_t b) { uint64_t v = a; v |= (uint64_t)b << 32; return v; } static void unpack_2x32(uint64_t p, uint32_t *a, uint32_t *b) { *a = p & 0xffffffff; *b = (p >> 32); } /** * Get the constant that is ultimately referenced by an r-value, in a constant * expression evaluation context. * * The offset is used when the reference is to a specific column of a matrix. */ static bool constant_referenced(const ir_dereference *deref, struct hash_table *variable_context, ir_constant *&store, int &offset) { store = NULL; offset = 0; if (variable_context == NULL) return false; switch (deref->ir_type) { case ir_type_dereference_array: { const ir_dereference_array *const da = (const ir_dereference_array *) deref; ir_constant *const index_c = da->array_index->constant_expression_value(variable_context); if (!index_c || !index_c->type->is_scalar() || !index_c->type->is_integer_32()) break; const int index = index_c->type->base_type == GLSL_TYPE_INT ? index_c->get_int_component(0) : index_c->get_uint_component(0); ir_constant *substore; int suboffset; const ir_dereference *const deref = da->array->as_dereference(); if (!deref) break; if (!constant_referenced(deref, variable_context, substore, suboffset)) break; const glsl_type *const vt = da->array->type; if (vt->is_array()) { store = substore->get_array_element(index); offset = 0; } else if (vt->is_matrix()) { store = substore; offset = index * vt->vector_elements; } else if (vt->is_vector()) { store = substore; offset = suboffset + index; } break; } case ir_type_dereference_record: { const ir_dereference_record *const dr = (const ir_dereference_record *) deref; const ir_dereference *const deref = dr->record->as_dereference(); if (!deref) break; ir_constant *substore; int suboffset; if (!constant_referenced(deref, variable_context, substore, suboffset)) break; /* Since we're dropping it on the floor... */ assert(suboffset == 0); store = substore->get_record_field(dr->field_idx); break; } case ir_type_dereference_variable: { const ir_dereference_variable *const dv = (const ir_dereference_variable *) deref; hash_entry *entry = _mesa_hash_table_search(variable_context, dv->var); if (entry) store = (ir_constant *) entry->data; break; } default: assert(!"Should not get here."); break; } return store != NULL; } ir_constant * ir_rvalue::constant_expression_value(void *, struct hash_table *) { assert(this->type->is_error()); return NULL; } static uint32_t bitfield_reverse(uint32_t v) { /* http://graphics.stanford.edu/~seander/bithacks.html#BitReverseObvious */ uint32_t r = v; // r will be reversed bits of v; first get LSB of v int s = sizeof(v) * CHAR_BIT - 1; // extra shift needed at end for (v >>= 1; v; v >>= 1) { r <<= 1; r |= v & 1; s--; } r <<= s; // shift when v's highest bits are zero return r; } static int find_msb_uint(uint32_t v) { int count = 0; /* If v == 0, then the loop will terminate when count == 32. In that case * 31-count will produce the -1 result required by GLSL findMSB(). */ while (((v & (1u << 31)) == 0) && count != 32) { count++; v <<= 1; } return 31 - count; } static int find_msb_int(int32_t v) { /* If v is signed, findMSB() returns the position of the most significant * zero bit. */ return find_msb_uint(v < 0 ? ~v : v); } static float ldexpf_flush_subnormal(float x, int exp) { const float result = ldexpf(x, exp); /* Flush subnormal values to zero. */ return !isnormal(result) ? copysignf(0.0f, x) : result; } static double ldexp_flush_subnormal(double x, int exp) { const double result = ldexp(x, exp); /* Flush subnormal values to zero. */ return !isnormal(result) ? copysign(0.0, x) : result; } static uint32_t bitfield_extract_uint(uint32_t value, int offset, int bits) { if (bits == 0) return 0; else if (offset < 0 || bits < 0) return 0; /* Undefined, per spec. */ else if (offset + bits > 32) return 0; /* Undefined, per spec. */ else { value <<= 32 - bits - offset; value >>= 32 - bits; return value; } } static int32_t bitfield_extract_int(int32_t value, int offset, int bits) { if (bits == 0) return 0; else if (offset < 0 || bits < 0) return 0; /* Undefined, per spec. */ else if (offset + bits > 32) return 0; /* Undefined, per spec. */ else { value <<= 32 - bits - offset; value >>= 32 - bits; return value; } } static uint32_t bitfield_insert(uint32_t base, uint32_t insert, int offset, int bits) { if (bits == 0) return base; else if (offset < 0 || bits < 0) return 0; /* Undefined, per spec. */ else if (offset + bits > 32) return 0; /* Undefined, per spec. */ else { unsigned insert_mask = ((1ull << bits) - 1) << offset; insert <<= offset; insert &= insert_mask; base &= ~insert_mask; return base | insert; } } ir_constant * ir_expression::constant_expression_value(void *mem_ctx, struct hash_table *variable_context) { assert(mem_ctx); if (this->type->is_error()) return NULL; ir_constant *op[ARRAY_SIZE(this->operands)] = { NULL, }; ir_constant_data data; memset(&data, 0, sizeof(data)); for (unsigned operand = 0; operand < this->num_operands; operand++) { op[operand] = this->operands[operand]->constant_expression_value(mem_ctx, variable_context); if (!op[operand]) return NULL; } for (unsigned operand = 0; operand < this->num_operands; operand++) { switch (op[operand]->type->base_type) { case GLSL_TYPE_FLOAT16: { const struct glsl_type *float_type = glsl_type::get_instance(GLSL_TYPE_FLOAT, op[operand]->type->vector_elements, op[operand]->type->matrix_columns, op[operand]->type->explicit_stride, op[operand]->type->interface_row_major); ir_constant_data f; for (unsigned i = 0; i < ARRAY_SIZE(f.f); i++) f.f[i] = _mesa_half_to_float(op[operand]->value.f16[i]); op[operand] = new(mem_ctx) ir_constant(float_type, &f); break; } case GLSL_TYPE_INT16: { const struct glsl_type *int_type = glsl_type::get_instance(GLSL_TYPE_INT, op[operand]->type->vector_elements, op[operand]->type->matrix_columns, op[operand]->type->explicit_stride, op[operand]->type->interface_row_major); ir_constant_data d; for (unsigned i = 0; i < ARRAY_SIZE(d.i); i++) d.i[i] = op[operand]->value.i16[i]; op[operand] = new(mem_ctx) ir_constant(int_type, &d); break; } case GLSL_TYPE_UINT16: { const struct glsl_type *uint_type = glsl_type::get_instance(GLSL_TYPE_UINT, op[operand]->type->vector_elements, op[operand]->type->matrix_columns, op[operand]->type->explicit_stride, op[operand]->type->interface_row_major); ir_constant_data d; for (unsigned i = 0; i < ARRAY_SIZE(d.u); i++) d.u[i] = op[operand]->value.u16[i]; op[operand] = new(mem_ctx) ir_constant(uint_type, &d); break; } default: /* nothing to do */ break; } } if (op[1] != NULL) switch (this->operation) { case ir_binop_lshift: case ir_binop_rshift: case ir_binop_ldexp: case ir_binop_interpolate_at_offset: case ir_binop_interpolate_at_sample: case ir_binop_vector_extract: case ir_triop_csel: case ir_triop_bitfield_extract: break; default: assert(op[0]->type->base_type == op[1]->type->base_type); break; } bool op0_scalar = op[0]->type->is_scalar(); bool op1_scalar = op[1] != NULL && op[1]->type->is_scalar(); /* When iterating over a vector or matrix's components, we want to increase * the loop counter. However, for scalars, we want to stay at 0. */ unsigned c0_inc = op0_scalar ? 0 : 1; unsigned c1_inc = op1_scalar ? 0 : 1; unsigned components; if (op1_scalar || !op[1]) { components = op[0]->type->components(); } else { components = op[1]->type->components(); } /* Handle array operations here, rather than below. */ if (op[0]->type->is_array()) { assert(op[1] != NULL && op[1]->type->is_array()); switch (this->operation) { case ir_binop_all_equal: return new(mem_ctx) ir_constant(op[0]->has_value(op[1])); case ir_binop_any_nequal: return new(mem_ctx) ir_constant(!op[0]->has_value(op[1])); default: break; } return NULL; } #include "ir_expression_operation_constant.h" switch (type->base_type) { case GLSL_TYPE_FLOAT16: { ir_constant_data f; for (unsigned i = 0; i < ARRAY_SIZE(f.f16); i++) f.f16[i] = _mesa_float_to_half(data.f[i]); return new(mem_ctx) ir_constant(this->type, &f); } case GLSL_TYPE_INT16: { ir_constant_data d; for (unsigned i = 0; i < ARRAY_SIZE(d.i16); i++) d.i16[i] = data.i[i]; return new(mem_ctx) ir_constant(this->type, &d); } case GLSL_TYPE_UINT16: { ir_constant_data d; for (unsigned i = 0; i < ARRAY_SIZE(d.u16); i++) d.u16[i] = data.u[i]; return new(mem_ctx) ir_constant(this->type, &d); } default: return new(mem_ctx) ir_constant(this->type, &data); } } ir_constant * ir_texture::constant_expression_value(void *, struct hash_table *) { /* texture lookups aren't constant expressions */ return NULL; } ir_constant * ir_swizzle::constant_expression_value(void *mem_ctx, struct hash_table *variable_context) { assert(mem_ctx); ir_constant *v = this->val->constant_expression_value(mem_ctx, variable_context); if (v != NULL) { ir_constant_data data = { { 0 } }; const unsigned swiz_idx[4] = { this->mask.x, this->mask.y, this->mask.z, this->mask.w }; for (unsigned i = 0; i < this->mask.num_components; i++) { switch (v->type->base_type) { case GLSL_TYPE_UINT16: case GLSL_TYPE_INT16: data.u16[i] = v->value.u16[swiz_idx[i]]; break; case GLSL_TYPE_UINT: case GLSL_TYPE_INT: data.u[i] = v->value.u[swiz_idx[i]]; break; case GLSL_TYPE_FLOAT: data.f[i] = v->value.f[swiz_idx[i]]; break; case GLSL_TYPE_FLOAT16: data.f16[i] = v->value.f16[swiz_idx[i]]; break; case GLSL_TYPE_BOOL: data.b[i] = v->value.b[swiz_idx[i]]; break; case GLSL_TYPE_DOUBLE:data.d[i] = v->value.d[swiz_idx[i]]; break; case GLSL_TYPE_UINT64:data.u64[i] = v->value.u64[swiz_idx[i]]; break; case GLSL_TYPE_INT64: data.i64[i] = v->value.i64[swiz_idx[i]]; break; default: assert(!"Should not get here."); break; } } return new(mem_ctx) ir_constant(this->type, &data); } return NULL; } ir_constant * ir_dereference_variable::constant_expression_value(void *mem_ctx, struct hash_table *variable_context) { assert(var); assert(mem_ctx); /* Give priority to the context hashtable, if it exists */ if (variable_context) { hash_entry *entry = _mesa_hash_table_search(variable_context, var); if(entry) return (ir_constant *) entry->data; } /* The constant_value of a uniform variable is its initializer, * not the lifetime constant value of the uniform. */ if (var->data.mode == ir_var_uniform) return NULL; if (!var->constant_value) return NULL; return var->constant_value->clone(mem_ctx, NULL); } ir_constant * ir_dereference_array::constant_expression_value(void *mem_ctx, struct hash_table *variable_context) { assert(mem_ctx); ir_constant *array = this->array->constant_expression_value(mem_ctx, variable_context); ir_constant *idx = this->array_index->constant_expression_value(mem_ctx, variable_context); if ((array != NULL) && (idx != NULL)) { if (array->type->is_matrix()) { /* Array access of a matrix results in a vector. */ const unsigned column = idx->value.u[0]; const glsl_type *const column_type = array->type->column_type(); /* Offset in the constant matrix to the first element of the column * to be extracted. */ const unsigned mat_idx = column * column_type->vector_elements; ir_constant_data data = { { 0 } }; switch (column_type->base_type) { case GLSL_TYPE_FLOAT16: for (unsigned i = 0; i < column_type->vector_elements; i++) data.f16[i] = array->value.f16[mat_idx + i]; break; case GLSL_TYPE_FLOAT: for (unsigned i = 0; i < column_type->vector_elements; i++) data.f[i] = array->value.f[mat_idx + i]; break; case GLSL_TYPE_DOUBLE: for (unsigned i = 0; i < column_type->vector_elements; i++) data.d[i] = array->value.d[mat_idx + i]; break; default: unreachable("Matrix types are either float or double."); } return new(mem_ctx) ir_constant(column_type, &data); } else if (array->type->is_vector()) { const unsigned component = idx->value.u[0]; return new(mem_ctx) ir_constant(array, component); } else if (array->type->is_array()) { const unsigned index = idx->value.u[0]; return array->get_array_element(index)->clone(mem_ctx, NULL); } } return NULL; } ir_constant * ir_dereference_record::constant_expression_value(void *mem_ctx, struct hash_table *) { assert(mem_ctx); ir_constant *v = this->record->constant_expression_value(mem_ctx); return (v != NULL) ? v->get_record_field(this->field_idx) : NULL; } ir_constant * ir_assignment::constant_expression_value(void *, struct hash_table *) { /* FINISHME: Handle CEs involving assignment (return RHS) */ return NULL; } ir_constant * ir_constant::constant_expression_value(void *, struct hash_table *) { return this; } ir_constant * ir_call::constant_expression_value(void *mem_ctx, struct hash_table *variable_context) { assert(mem_ctx); return this->callee->constant_expression_value(mem_ctx, &this->actual_parameters, variable_context); } bool ir_function_signature::constant_expression_evaluate_expression_list(void *mem_ctx, const struct exec_list &body, struct hash_table *variable_context, ir_constant **result) { assert(mem_ctx); foreach_in_list(ir_instruction, inst, &body) { switch(inst->ir_type) { /* (declare () type symbol) */ case ir_type_variable: { ir_variable *var = inst->as_variable(); _mesa_hash_table_insert(variable_context, var, ir_constant::zero(this, var->type)); break; } /* (assign [condition] (write-mask) (ref) (value)) */ case ir_type_assignment: { ir_assignment *asg = inst->as_assignment(); if (asg->condition) { ir_constant *cond = asg->condition->constant_expression_value(mem_ctx, variable_context); if (!cond) return false; if (!cond->get_bool_component(0)) break; } ir_constant *store = NULL; int offset = 0; if (!constant_referenced(asg->lhs, variable_context, store, offset)) return false; ir_constant *value = asg->rhs->constant_expression_value(mem_ctx, variable_context); if (!value) return false; store->copy_masked_offset(value, offset, asg->write_mask); break; } /* (return (expression)) */ case ir_type_return: assert (result); *result = inst->as_return()->value->constant_expression_value(mem_ctx, variable_context); return *result != NULL; /* (call name (ref) (params))*/ case ir_type_call: { ir_call *call = inst->as_call(); /* Just say no to void functions in constant expressions. We * don't need them at that point. */ if (!call->return_deref) return false; ir_constant *store = NULL; int offset = 0; if (!constant_referenced(call->return_deref, variable_context, store, offset)) return false; ir_constant *value = call->constant_expression_value(mem_ctx, variable_context); if(!value) return false; store->copy_offset(value, offset); break; } /* (if condition (then-instructions) (else-instructions)) */ case ir_type_if: { ir_if *iif = inst->as_if(); ir_constant *cond = iif->condition->constant_expression_value(mem_ctx, variable_context); if (!cond || !cond->type->is_boolean()) return false; exec_list &branch = cond->get_bool_component(0) ? iif->then_instructions : iif->else_instructions; *result = NULL; if (!constant_expression_evaluate_expression_list(mem_ctx, branch, variable_context, result)) return false; /* If there was a return in the branch chosen, drop out now. */ if (*result) return true; break; } /* Every other expression type, we drop out. */ default: return false; } } /* Reaching the end of the block is not an error condition */ if (result) *result = NULL; return true; } ir_constant * ir_function_signature::constant_expression_value(void *mem_ctx, exec_list *actual_parameters, struct hash_table *variable_context) { assert(mem_ctx); const glsl_type *type = this->return_type; if (type == glsl_type::void_type) return NULL; /* From the GLSL 1.20 spec, page 23: * "Function calls to user-defined functions (non-built-in functions) * cannot be used to form constant expressions." */ if (!this->is_builtin()) return NULL; /* * Of the builtin functions, only the texture lookups and the noise * ones must not be used in constant expressions. Texture instructions * include special ir_texture opcodes which can't be constant-folded (see * ir_texture::constant_expression_value). Noise functions, however, we * have to special case here. */ if (strcmp(this->function_name(), "noise1") == 0 || strcmp(this->function_name(), "noise2") == 0 || strcmp(this->function_name(), "noise3") == 0 || strcmp(this->function_name(), "noise4") == 0) return NULL; /* Initialize the table of dereferencable names with the function * parameters. Verify their const-ness on the way. * * We expect the correctness of the number of parameters to have * been checked earlier. */ hash_table *deref_hash = _mesa_pointer_hash_table_create(NULL); /* If "origin" is non-NULL, then the function body is there. So we * have to use the variable objects from the object with the body, * but the parameter instanciation on the current object. */ const exec_node *parameter_info = origin ? origin->parameters.get_head_raw() : parameters.get_head_raw(); foreach_in_list(ir_rvalue, n, actual_parameters) { ir_constant *constant = n->constant_expression_value(mem_ctx, variable_context); if (constant == NULL) { _mesa_hash_table_destroy(deref_hash, NULL); return NULL; } ir_variable *var = (ir_variable *)parameter_info; _mesa_hash_table_insert(deref_hash, var, constant); parameter_info = parameter_info->next; } ir_constant *result = NULL; /* Now run the builtin function until something non-constant * happens or we get the result. */ if (constant_expression_evaluate_expression_list(mem_ctx, origin ? origin->body : body, deref_hash, &result) && result) result = result->clone(mem_ctx, NULL); _mesa_hash_table_destroy(deref_hash, NULL); return result; }