Bug Summary

File:root/firefox-clang/third_party/rust/glslopt/glsl-optimizer/src/compiler/glsl/lower_int64.cpp
Warning:line 226, column 23
Assigned value is uninitialized

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-unknown-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name lower_int64.cpp -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -ffp-contract=off -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/root/firefox-clang/third_party/rust/glslopt -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/root/firefox-clang/third_party/rust/glslopt -resource-dir /usr/lib/llvm-21/lib/clang/21 -include /root/firefox-clang/config/gcc_hidden.h -include /root/firefox-clang/obj-x86_64-pc-linux-gnu/mozilla-config.h -I glsl-optimizer/include -I glsl-optimizer/src/mesa -I glsl-optimizer/src/mapi -I glsl-optimizer/src/compiler -I glsl-optimizer/src/compiler/glsl -I glsl-optimizer/src/gallium/auxiliary -I glsl-optimizer/src/gallium/include -I glsl-optimizer/src -I glsl-optimizer/src/util -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/stl_wrappers -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/system_wrappers -U _FORTIFY_SOURCE -D _FORTIFY_SOURCE=2 -D _GLIBCXX_ASSERTIONS -D DEBUG=1 -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include/nspr -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include/nss -D MOZILLA_CLIENT -D MOZILLA_CONFIG_H -D __STDC_FORMAT_MACROS -D _GNU_SOURCE -D HAVE_ENDIAN_H -D HAVE_PTHREAD -D HAVE_TIMESPEC_GET -D MOZ_INCLUDE_MOZALLOC_H -D mozilla_throw_gcc_h -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/14/../../../../include/x86_64-linux-gnu/c++/14 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14/backward -internal-isystem /usr/lib/llvm-21/lib/clang/21/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/14/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-error=pessimizing-move -Wno-error=large-by-value-copy=128 -Wno-error=implicit-int-float-conversion -Wno-error=thread-safety-analysis -Wno-error=tautological-type-limit-compare -Wno-invalid-offsetof -Wno-range-loop-analysis -Wno-deprecated-anon-enum-enum-conversion -Wno-deprecated-enum-enum-conversion -Wno-deprecated-this-capture -Wno-inline-new-delete -Wno-error=deprecated-declarations -Wno-error=array-bounds -Wno-error=free-nonheap-object -Wno-error=atomic-alignment -Wno-error=deprecated-builtins -Wno-psabi -Wno-error=builtin-macro-redefined -Wno-vla-cxx-extension -Wno-unknown-warning-option -fdeprecated-macro -ferror-limit 19 -fstrict-flex-arrays=1 -stack-protector 2 -fstack-clash-protection -ftrivial-auto-var-init=pattern -fno-rtti -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fno-sized-deallocation -fno-aligned-allocation -vectorize-loops -vectorize-slp -analyzer-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2025-06-27-100320-3286336-1 -x c++ glsl-optimizer/src/compiler/glsl/lower_int64.cpp
1/*
2 * Copyright © 2016 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 */
23
24/**
25 * \file lower_int64.cpp
26 *
27 * Lower 64-bit operations to 32-bit operations. Each 64-bit value is lowered
28 * to a uvec2. For each operation that can be lowered, there is a function
29 * called __builtin_foo with the same number of parameters that takes uvec2
30 * sources and produces uvec2 results. An operation like
31 *
32 * uint64_t(x) * uint64_t(y)
33 *
34 * becomes
35 *
36 * packUint2x32(__builtin_umul64(unpackUint2x32(x), unpackUint2x32(y)));
37 */
38
39#include "main/macros.h"
40#include "compiler/glsl_types.h"
41#include "ir.h"
42#include "ir_rvalue_visitor.h"
43#include "ir_builder.h"
44#include "ir_optimization.h"
45#include "util/hash_table.h"
46#include "builtin_functions.h"
47
48typedef ir_function_signature *(*function_generator)(void *mem_ctx,
49 builtin_available_predicate avail);
50
51using namespace ir_builder;
52
53namespace lower_64bit {
54void expand_source(ir_factory &, ir_rvalue *val, ir_variable **expanded_src);
55
56ir_dereference_variable *compact_destination(ir_factory &,
57 const glsl_type *type,
58 ir_variable *result[4]);
59
60ir_rvalue *lower_op_to_function_call(ir_instruction *base_ir,
61 ir_expression *ir,
62 ir_function_signature *callee);
63};
64
65using namespace lower_64bit;
66
67namespace {
68
69class lower_64bit_visitor : public ir_rvalue_visitor {
70public:
71 lower_64bit_visitor(void *mem_ctx, exec_list *instructions, unsigned lower)
72 : progress(false), lower(lower),
73 function_list(), added_functions(&function_list, mem_ctx)
74 {
75 functions = _mesa_hash_table_create(mem_ctx,
76 _mesa_hash_string,
77 _mesa_key_string_equal);
78
79 foreach_in_list(ir_instruction, node, instructions)for (ir_instruction *node = (!exec_node_is_tail_sentinel((instructions
)->head_sentinel.next) ? (ir_instruction *) ((instructions
)->head_sentinel.next) : __null); (node) != __null; (node)
= (!exec_node_is_tail_sentinel((node)->next) ? (ir_instruction
*) ((node)->next) : __null)) {
80 ir_function *const f = node->as_function();
81
82 if (f == NULL__null || strncmp(f->name, "__builtin_", 10) != 0)
83 continue;
84
85 add_function(f);
86 }
87 }
88
89 ~lower_64bit_visitor()
90 {
91 _mesa_hash_table_destroy(functions, NULL__null);
92 }
93
94 void handle_rvalue(ir_rvalue **rvalue);
95
96 void add_function(ir_function *f)
97 {
98 _mesa_hash_table_insert(functions, f->name, f);
99 }
100
101 ir_function *find_function(const char *name)
102 {
103 struct hash_entry *const entry =
104 _mesa_hash_table_search(functions, name);
105
106 return entry != NULL__null ? (ir_function *) entry->data : NULL__null;
107 }
108
109 bool progress;
110
111private:
112 unsigned lower; /** Bitfield of which operations to lower */
113
114 /** Hashtable containing all of the known functions in the IR */
115 struct hash_table *functions;
116
117public:
118 exec_list function_list;
119
120private:
121 ir_factory added_functions;
122
123 ir_rvalue *handle_op(ir_expression *ir, const char *function_name,
124 function_generator generator);
125};
126
127} /* anonymous namespace */
128
129/**
130 * Determine if a particular type of lowering should occur
131 */
132#define lowering(x)(this->lower & x) (this->lower & x)
133
134bool
135lower_64bit_integer_instructions(exec_list *instructions,
136 unsigned what_to_lower)
137{
138 if (instructions->is_empty())
139 return false;
140
141 ir_instruction *first_inst = (ir_instruction *) instructions->get_head_raw();
142 void *const mem_ctx = ralloc_parent(first_inst);
143 lower_64bit_visitor v(mem_ctx, instructions, what_to_lower);
144
145 visit_list_elements(&v, instructions);
146
147 if (v.progress && !v.function_list.is_empty()) {
148 /* Move all of the nodes from function_list to the head if the incoming
149 * instruction list.
150 */
151 exec_node *const after = &instructions->head_sentinel;
152 exec_node *const before = instructions->head_sentinel.next;
153 exec_node *const head = v.function_list.head_sentinel.next;
154 exec_node *const tail = v.function_list.tail_sentinel.prev;
155
156 before->next = head;
157 head->prev = before;
158
159 after->prev = tail;
160 tail->next = after;
161 }
162
163 return v.progress;
164}
165
166
167/**
168 * Expand individual 64-bit values to uvec2 values
169 *
170 * Each operation is in one of a few forms.
171 *
172 * vector op vector
173 * vector op scalar
174 * scalar op vector
175 * scalar op scalar
176 *
177 * In the 'vector op vector' case, the two vectors must have the same size.
178 * In a way, the 'scalar op scalar' form is special case of the 'vector op
179 * vector' form.
180 *
181 * This method generates a new set of uvec2 values for each element of a
182 * single operand. If the operand is a scalar, the uvec2 is replicated
183 * multiple times. A value like
184 *
185 * u64vec3(a) + u64vec3(b)
186 *
187 * becomes
188 *
189 * u64vec3 tmp0 = u64vec3(a) + u64vec3(b);
190 * uvec2 tmp1 = unpackUint2x32(tmp0.x);
191 * uvec2 tmp2 = unpackUint2x32(tmp0.y);
192 * uvec2 tmp3 = unpackUint2x32(tmp0.z);
193 *
194 * and the returned operands array contains ir_variable pointers to
195 *
196 * { tmp1, tmp2, tmp3, tmp1 }
197 */
198void
199lower_64bit::expand_source(ir_factory &body,
200 ir_rvalue *val,
201 ir_variable **expanded_src)
202{
203 assert(val->type->is_integer_64())(static_cast <bool> (val->type->is_integer_64()) ?
void (0) : __assert_fail ("val->type->is_integer_64()"
, __builtin_FILE (), __builtin_LINE (), __extension__ __PRETTY_FUNCTION__
));
20
←
'?' condition is true
→
204
205 ir_variable *const temp = body.make_temp(val->type, "tmp");
206
207 body.emit(assign(temp, val));
208
209 const ir_expression_operation unpack_opcode =
210 val->type->base_type == GLSL_TYPE_UINT64
21
←
Assuming field 'base_type' is equal to GLSL_TYPE_UINT64
→
22
←
'?' condition is true
→
211 ? ir_unop_unpack_uint_2x32 : ir_unop_unpack_int_2x32;
212
213 const glsl_type *const type =
214 val->type->base_type
22.1
Field 'base_type' is equal to GLSL_TYPE_UINT64
 == GLSL_TYPE_UINT64
23
←
'?' condition is true
→
215 ? glsl_type::uvec2_type : glsl_type::ivec2_type;
216
217 unsigned i;
218 for (i = 0; i < val->type->vector_elements; i++) {
24
←
Assuming 'i' is >= field 'vector_elements'
→
25
←
Loop condition is false. Execution continues on line 225
→
219 expanded_src[i] = body.make_temp(type, "expanded_64bit_source");
220
221 body.emit(assign(expanded_src[i],
222 expr(unpack_opcode, swizzle(temp, i, 1))));
223 }
224
225 for (/* empty */; i < 4; i++)
26
←
Loop condition is true. Entering loop body
→
226 expanded_src[i] = expanded_src[0];
27
←
Assigned value is uninitialized
227}
228
229/**
230 * Convert a series of uvec2 results into a single 64-bit integer vector
231 */
232ir_dereference_variable *
233lower_64bit::compact_destination(ir_factory &body,
234 const glsl_type *type,
235 ir_variable *result[4])
236{
237 const ir_expression_operation pack_opcode =
238 type->base_type == GLSL_TYPE_UINT64
239 ? ir_unop_pack_uint_2x32 : ir_unop_pack_int_2x32;
240
241 ir_variable *const compacted_result =
242 body.make_temp(type, "compacted_64bit_result");
243
244 for (unsigned i = 0; i < type->vector_elements; i++) {
245 body.emit(assign(compacted_result,
246 expr(pack_opcode, result[i]),
247 1U << i));
248 }
249
250 void *const mem_ctx = ralloc_parent(compacted_result);
251 return new(mem_ctx) ir_dereference_variable(compacted_result);
252}
253
254ir_rvalue *
255lower_64bit::lower_op_to_function_call(ir_instruction *base_ir,
256 ir_expression *ir,
257 ir_function_signature *callee)
258{
259 const unsigned num_operands = ir->num_operands;
260 ir_variable *src[4][4];
261 ir_variable *dst[4];
262 void *const mem_ctx = ralloc_parent(ir);
263 exec_list instructions;
264 unsigned source_components = 0;
265 const glsl_type *const result_type =
266 ir->type->base_type == GLSL_TYPE_UINT64
16
←
Assuming field 'base_type' is equal to GLSL_TYPE_UINT64
→
17
←
'?' condition is true
→
267 ? glsl_type::uvec2_type : glsl_type::ivec2_type;
268
269 ir_factory body(&instructions, mem_ctx);
270
271 for (unsigned i = 0; i < num_operands; i++) {
18
←
Loop condition is true. Entering loop body
→
272 expand_source(body, ir->operands[i], src[i]);
19
←
Calling 'expand_source'
→
273
274 if (ir->operands[i]->type->vector_elements > source_components)
275 source_components = ir->operands[i]->type->vector_elements;
276 }
277
278 for (unsigned i = 0; i < source_components; i++) {
279 dst[i] = body.make_temp(result_type, "expanded_64bit_result");
280
281 exec_list parameters;
282
283 for (unsigned j = 0; j < num_operands; j++)
284 parameters.push_tail(new(mem_ctx) ir_dereference_variable(src[j][i]));
285
286 ir_dereference_variable *const return_deref =
287 new(mem_ctx) ir_dereference_variable(dst[i]);
288
289 ir_call *const c = new(mem_ctx) ir_call(callee,
290 return_deref,
291 &parameters);
292
293 body.emit(c);
294 }
295
296 ir_rvalue *const rv = compact_destination(body, ir->type, dst);
297
298 /* Move all of the nodes from instructions between base_ir and the
299 * instruction before it.
300 */
301 exec_node *const after = base_ir;
302 exec_node *const before = after->prev;
303 exec_node *const head = instructions.head_sentinel.next;
304 exec_node *const tail = instructions.tail_sentinel.prev;
305
306 before->next = head;
307 head->prev = before;
308
309 after->prev = tail;
310 tail->next = after;
311
312 return rv;
313}
314
315ir_rvalue *
316lower_64bit_visitor::handle_op(ir_expression *ir,
317 const char *function_name,
318 function_generator generator)
319{
320 for (unsigned i = 0; i < ir->num_operands; i++)
9
←
Assuming 'i' is < field 'num_operands'
→
10
←
Loop condition is true. Entering loop body
→
12
←
Assuming 'i' is >= field 'num_operands'
→
13
←
Loop condition is false. Execution continues on line 327
→
321 if (!ir->operands[i]->type->is_integer_64())
11
←
Taking false branch
→
322 return ir;
323
324 /* Get a handle to the correct ir_function_signature for the core
325 * operation.
326 */
327 ir_function_signature *callee = NULL__null;
328 ir_function *f = find_function(function_name);
329
330 if (f
13.1
'f' is equal to NULL
 != NULL__null) {
14
←
Taking false branch
→
331 callee = (ir_function_signature *) f->signatures.get_head();
332 assert(callee != NULL && callee->ir_type == ir_type_function_signature)(static_cast <bool> (callee != __null && callee
->ir_type == ir_type_function_signature) ? void (0) : __assert_fail
("callee != NULL && callee->ir_type == ir_type_function_signature"
, __builtin_FILE (), __builtin_LINE (), __extension__ __PRETTY_FUNCTION__
));
333 } else {
334 f = new(base_ir) ir_function(function_name);
335 callee = generator(base_ir, NULL__null);
336
337 f->add_signature(callee);
338
339 add_function(f);
340 }
341
342 this->progress = true;
343 return lower_op_to_function_call(this->base_ir, ir, callee);
15
←
Calling 'lower_op_to_function_call'
→
344}
345
346void
347lower_64bit_visitor::handle_rvalue(ir_rvalue **rvalue)
348{
349 if (*rvalue == NULL__null || (*rvalue)->ir_type != ir_type_expression)
1
Assuming the condition is false
→
2
←
Assuming field 'ir_type' is equal to ir_type_expression
→
3
←
Taking false branch
→
350 return;
351
352 ir_expression *const ir = (*rvalue)->as_expression();
353 assert(ir != NULL)(static_cast <bool> (ir != __null) ? void (0) : __assert_fail
("ir != NULL", __builtin_FILE (), __builtin_LINE (), __extension__
__PRETTY_FUNCTION__));
4
←
'?' condition is true
→
354
355 switch (ir->operation) {
5
←
Control jumps to 'case ir_binop_mul:' at line 382
→
356 case ir_unop_sign:
357 if (lowering(SIGN64)(this->lower & (1U << 1))) {
358 *rvalue = handle_op(ir, "__builtin_sign64", generate_ir::sign64);
359 }
360 break;
361
362 case ir_binop_div:
363 if (lowering(DIV64)(this->lower & (1U << 2))) {
364 if (ir->type->base_type == GLSL_TYPE_UINT64) {
365 *rvalue = handle_op(ir, "__builtin_udiv64", generate_ir::udiv64);
366 } else {
367 *rvalue = handle_op(ir, "__builtin_idiv64", generate_ir::idiv64);
368 }
369 }
370 break;
371
372 case ir_binop_mod:
373 if (lowering(MOD64)(this->lower & (1U << 3))) {
374 if (ir->type->base_type == GLSL_TYPE_UINT64) {
375 *rvalue = handle_op(ir, "__builtin_umod64", generate_ir::umod64);
376 } else {
377 *rvalue = handle_op(ir, "__builtin_imod64", generate_ir::imod64);
378 }
379 }
380 break;
381
382 case ir_binop_mul:
383 if (lowering(MUL64)(this->lower & (1U << 0))) {
6
←
Assuming the condition is true
→
7
←
Taking true branch
→
384 *rvalue = handle_op(ir, "__builtin_umul64", generate_ir::umul64);
8
←
Calling 'lower_64bit_visitor::handle_op'
→
385 }
386 break;
387
388 default:
389 break;
390 }
391}