clang/test/CodeGenCXX/trivial-auto-var-init.cpp

   1 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -fblocks %s -emit-llvm -o - | FileCheck %s -check-prefix=UNINIT
   2 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -fblocks -ftrivial-auto-var-init=pattern %s -emit-llvm -o - | FileCheck %s -check-prefix=PATTERN
   3 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -fblocks -ftrivial-auto-var-init=zero %s -emit-llvm -o - | FileCheck %s -check-prefix=ZERO
   4
   5 // None of the synthesized globals should contain `undef`.
   6 // PATTERN-NOT: undef
   7 // ZERO-NOT: undef
   8
   9 template<typename T> void used(T &) noexcept;
  10
  11 extern "C" {
  12
  13 // UNINIT-LABEL:  test_selfinit(
  14 // ZERO-LABEL:    test_selfinit(
  15 // ZERO: store i32 0, ptr %self, align 4, !annotation [[AUTO_INIT:!.+]]
  16 // PATTERN-LABEL: test_selfinit(
  17 // PATTERN: store i32 -1431655766, ptr %self, align 4, !annotation [[AUTO_INIT:!.+]]
  18 void test_selfinit() {
  19   int self = self + 1;
  20   used(self);
  21 }
  22
  23 // UNINIT-LABEL:  test_block(
  24 // ZERO-LABEL:    test_block(
  25 // ZERO: store i32 0, ptr %block, align 4, !annotation [[AUTO_INIT:!.+]]
  26 // PATTERN-LABEL: test_block(
  27 // PATTERN: store i32 -1431655766, ptr %block, align 4, !annotation [[AUTO_INIT:!.+]]
  28 void test_block() {
  29   __block int block;
  30   used(block);
  31 }
  32
  33 // Using the variable being initialized is typically UB in C, but for blocks we
  34 // can be nice: they imply extra book-keeping and we can do the auto-init before
  35 // any of said book-keeping.
  36 //
  37 // UNINIT-LABEL:  test_block_self_init(
  38 // ZERO-LABEL:    test_block_self_init(
  39 // ZERO:          %block = alloca <{ ptr, i32, i32, ptr, ptr, ptr }>, align 8
  40 // ZERO:          %captured1 = getelementptr inbounds %struct.__block_byref_captured, ptr %captured, i32 0, i32 4
  41 // ZERO-NEXT:     store ptr null, ptr %captured1, align 8, !annotation [[AUTO_INIT:!.+]]
  42 // ZERO:          %call = call ptr @create(
  43 // PATTERN-LABEL: test_block_self_init(
  44 // PATTERN:       %block = alloca <{ ptr, i32, i32, ptr, ptr, ptr }>, align 8
  45 // PATTERN:       %captured1 = getelementptr inbounds %struct.__block_byref_captured, ptr %captured, i32 0, i32 4
  46 // PATTERN-NEXT:  store ptr inttoptr (i64 -6148914691236517206 to ptr), ptr %captured1, align 8, !annotation [[AUTO_INIT:!.+]]
  47 // PATTERN:       %call = call ptr @create(
  48 using Block = void (^)();
  49 typedef struct XYZ {
  50   Block block;
  51 } * xyz_t;
  52 void test_block_self_init() {
  53   extern xyz_t create(Block block);
  54   __block xyz_t captured = create(^() {
  55     used(captured);
  56   });
  57 }
  58
  59 // Capturing with escape after initialization is also an edge case.
  60 //
  61 // UNINIT-LABEL:  test_block_captures_self_after_init(
  62 // ZERO-LABEL:    test_block_captures_self_after_init(
  63 // ZERO:          %block = alloca <{ ptr, i32, i32, ptr, ptr, ptr }>, align 8
  64 // ZERO:          %captured1 = getelementptr inbounds %struct.__block_byref_captured.1, ptr %captured, i32 0, i32 4
  65 // ZERO-NEXT:     store ptr null, ptr %captured1, align 8, !annotation [[AUTO_INIT:!.+]]
  66 // ZERO:          %call = call ptr @create(
  67 // PATTERN-LABEL: test_block_captures_self_after_init(
  68 // PATTERN:       %block = alloca <{ ptr, i32, i32, ptr, ptr, ptr }>, align 8
  69 // PATTERN:       %captured1 = getelementptr inbounds %struct.__block_byref_captured.1, ptr %captured, i32 0, i32 4
  70 // PATTERN-NEXT:  store ptr inttoptr (i64 -6148914691236517206 to ptr), ptr %captured1, align 8, !annotation [[AUTO_INIT:!.+]]
  71 // PATTERN:       %call = call ptr @create(
  72 void test_block_captures_self_after_init() {
  73   extern xyz_t create(Block block);
  74   __block xyz_t captured;
  75   captured = create(^() {
  76     used(captured);
  77   });
  78 }
  79
  80 // This type of code is currently not handled by zero / pattern initialization.
  81 // The test will break when that is fixed.
  82 // UNINIT-LABEL:  test_goto_unreachable_value(
  83 // ZERO-LABEL:    test_goto_unreachable_value(
  84 // ZERO-NOT: store {{.*}}%oops
  85 // PATTERN-LABEL: test_goto_unreachable_value(
  86 // PATTERN-NOT: store {{.*}}%oops
  87 void test_goto_unreachable_value() {
  88   goto jump;
  89   int oops;
  90  jump:
  91   used(oops);
  92 }
  93
  94 // This type of code is currently not handled by zero / pattern initialization.
  95 // The test will break when that is fixed.
  96 // UNINIT-LABEL:  test_goto(
  97 // ZERO-LABEL:    test_goto(
  98 // ZERO: if.then:
  99 // ZERO: br label %jump
 100 // ZERO: store i32 0, ptr %oops, align 4, !annotation [[AUTO_INIT:!.+]]
 101 // ZERO: br label %jump
 102 // ZERO: jump:
 103 // PATTERN-LABEL: test_goto(
 104 // PATTERN: if.then:
 105 // PATTERN: br label %jump
 106 // PATTERN: store i32 -1431655766, ptr %oops, align 4, !annotation [[AUTO_INIT:!.+]]
 107 // PATTERN: br label %jump
 108 // PATTERN: jump:
 109 void test_goto(int i) {
 110   if (i)
 111     goto jump;
 112   int oops;
 113  jump:
 114   used(oops);
 115 }
 116
 117 // This type of code is currently not handled by zero / pattern initialization.
 118 // The test will break when that is fixed.
 119 // UNINIT-LABEL:  test_switch(
 120 // ZERO-LABEL:    test_switch(
 121 // ZERO:      sw.bb:
 122 // ZERO-NEXT: store i32 0, ptr %oops, align 4, !annotation [[AUTO_INIT:!.+]]
 123 // ZERO:      sw.bb1:
 124 // ZERO-NEXT: call void @{{.*}}used
 125 // PATTERN-LABEL: test_switch(
 126 // PATTERN:      sw.bb:
 127 // PATTERN-NEXT: store i32 -1431655766, ptr %oops, align 4, !annotation [[AUTO_INIT:!.+]]
 128 // PATTERN:      sw.bb1:
 129 // PATTERN-NEXT: call void @{{.*}}used
 130 void test_switch(int i) {
 131   switch (i) {
 132   case 0:
 133     int oops;
 134     break;
 135   case 1:
 136     used(oops);
 137   }
 138 }
 139
 140 // UNINIT-LABEL:  test_vla(
 141 // ZERO-LABEL:    test_vla(
 142 // ZERO:  %[[SIZE:[0-9]+]] = mul nuw i64 %{{.*}}, 4
 143 // ZERO:  call void @llvm.memset{{.*}}(ptr align 16 %{{.*}}, i8 0, i64 %[[SIZE]], i1 false), !annotation [[AUTO_INIT:!.+]]
 144 // PATTERN-LABEL: test_vla(
 145 // PATTERN:  %vla.iszerosized = icmp eq i64 %{{.*}}, 0
 146 // PATTERN:  br i1 %vla.iszerosized, label %vla-init.cont, label %vla-setup.loop
 147 // PATTERN: vla-setup.loop:
 148 // PATTERN:  %[[SIZE:[0-9]+]] = mul nuw i64 %{{.*}}, 4
 149 // PATTERN:  %vla.end = getelementptr inbounds i8, ptr %vla, i64 %[[SIZE]]
 150 // PATTERN:  br label %vla-init.loop
 151 // PATTERN: vla-init.loop:
 152 // PATTERN:  %vla.cur = phi ptr [ %vla, %vla-setup.loop ], [ %vla.next, %vla-init.loop ]
 153 // PATTERN:  call void @llvm.memcpy{{.*}} %vla.cur, {{.*}}@__const.test_vla.vla{{.*}}), !annotation [[AUTO_INIT:!.+]]
 154 // PATTERN:  %vla.next = getelementptr inbounds i8, ptr %vla.cur, i64 4
 155 // PATTERN:  %vla-init.isdone = icmp eq ptr %vla.next, %vla.end
 156 // PATTERN:  br i1 %vla-init.isdone, label %vla-init.cont, label %vla-init.loop
 157 // PATTERN: vla-init.cont:
 158 // PATTERN:  call void @{{.*}}used
 159 void test_vla(int size) {
 160   // Variable-length arrays can't have a zero size according to C11 6.7.6.2/5.
 161   // Neither can they be negative-sized.
 162   //
 163   // We don't use the former fact because some code creates zero-sized VLAs and
 164   // doesn't use them. clang makes these share locations with other stack
 165   // values, which leads to initialization of the wrong values.
 166   //
 167   // We rely on the later fact because it generates better code.
 168   //
 169   // Both cases are caught by UBSan.
 170   int vla[size];
 171   int *ptr = vla;
 172   used(ptr);
 173 }
 174
 175 // UNINIT-LABEL:  test_alloca(
 176 // ZERO-LABEL:    test_alloca(
 177 // ZERO:          %[[SIZE:[a-z0-9]+]] = sext i32 %{{.*}} to i64
 178 // ZERO-NEXT:     %[[ALLOCA:[a-z0-9]+]] = alloca i8, i64 %[[SIZE]], align [[ALIGN:[0-9]+]]
 179 // ZERO-NEXT:     call void @llvm.memset{{.*}}(ptr align [[ALIGN]] %[[ALLOCA]], i8 0, i64 %[[SIZE]], i1 false), !annotation [[AUTO_INIT:!.+]]
 180 // PATTERN-LABEL: test_alloca(
 181 // PATTERN:       %[[SIZE:[a-z0-9]+]] = sext i32 %{{.*}} to i64
 182 // PATTERN-NEXT:  %[[ALLOCA:[a-z0-9]+]] = alloca i8, i64 %[[SIZE]], align [[ALIGN:[0-9]+]]
 183 // PATTERN-NEXT:  call void @llvm.memset{{.*}}(ptr align [[ALIGN]] %[[ALLOCA]], i8 -86, i64 %[[SIZE]], i1 false), !annotation [[AUTO_INIT:!.+]]
 184 void test_alloca(int size) {
 185   void *ptr = __builtin_alloca(size);
 186   used(ptr);
 187 }
 188
 189 // UNINIT-LABEL:  test_alloca_with_align(
 190 // ZERO-LABEL:    test_alloca_with_align(
 191 // ZERO:          %[[SIZE:[a-z0-9]+]] = sext i32 %{{.*}} to i64
 192 // ZERO-NEXT:     %[[ALLOCA:[a-z0-9]+]] = alloca i8, i64 %[[SIZE]], align 128
 193 // ZERO-NEXT:     call void @llvm.memset{{.*}}(ptr align 128 %[[ALLOCA]], i8 0, i64 %[[SIZE]], i1 false), !annotation [[AUTO_INIT:!.+]]
 194 // PATTERN-LABEL: test_alloca_with_align(
 195 // PATTERN:       %[[SIZE:[a-z0-9]+]] = sext i32 %{{.*}} to i64
 196 // PATTERN-NEXT:  %[[ALLOCA:[a-z0-9]+]] = alloca i8, i64 %[[SIZE]], align 128
 197 // PATTERN-NEXT:  call void @llvm.memset{{.*}}(ptr align 128 %[[ALLOCA]], i8 -86, i64 %[[SIZE]], i1 false), !annotation [[AUTO_INIT:!.+]]
 198 void test_alloca_with_align(int size) {
 199   void *ptr = __builtin_alloca_with_align(size, 1024);
 200   used(ptr);
 201 }
 202
 203 // UNINIT-LABEL:  test_alloca_uninitialized(
 204 // ZERO-LABEL:    test_alloca_uninitialized(
 205 // ZERO:          %[[SIZE:[a-z0-9]+]] = sext i32 %{{.*}} to i64
 206 // ZERO-NEXT:     %[[ALLOCA:[a-z0-9]+]] = alloca i8, i64 %[[SIZE]], align [[ALIGN:[0-9]+]]
 207 // ZERO-NOT:      call void @llvm.memset
 208 // PATTERN-LABEL: test_alloca_uninitialized(
 209 // PATTERN:       %[[SIZE:[a-z0-9]+]] = sext i32 %{{.*}} to i64
 210 // PATTERN-NEXT:  %[[ALLOCA:[a-z0-9]+]] = alloca i8, i64 %[[SIZE]], align [[ALIGN:[0-9]+]]
 211 // PATTERN-NOT:   call void @llvm.memset
 212 void test_alloca_uninitialized(int size) {
 213   void *ptr = __builtin_alloca_uninitialized(size);
 214   used(ptr);
 215 }
 216
 217 // UNINIT-LABEL:  test_alloca_with_align_uninitialized(
 218 // ZERO-LABEL:    test_alloca_with_align_uninitialized(
 219 // ZERO:          %[[SIZE:[a-z0-9]+]] = sext i32 %{{.*}} to i64
 220 // ZERO-NEXT:     %[[ALLOCA:[a-z0-9]+]] = alloca i8, i64 %[[SIZE]], align 128
 221 // ZERO-NOT:      call void @llvm.memset
 222 // PATTERN-LABEL: test_alloca_with_align_uninitialized(
 223 // PATTERN:       %[[SIZE:[a-z0-9]+]] = sext i32 %{{.*}} to i64
 224 // PATTERN-NEXT:  %[[ALLOCA:[a-z0-9]+]] = alloca i8, i64 %[[SIZE]], align 128
 225 // PATTERN-NOT:   call void @llvm.memset
 226 void test_alloca_with_align_uninitialized(int size) {
 227   void *ptr = __builtin_alloca_with_align_uninitialized(size, 1024);
 228   used(ptr);
 229 }
 230
 231 // UNINIT-LABEL:  test_struct_vla(
 232 // ZERO-LABEL:    test_struct_vla(
 233 // ZERO:  %[[SIZE:[0-9]+]] = mul nuw i64 %{{.*}}, 16
 234 // ZERO:  call void @llvm.memset{{.*}}(ptr align 16 %{{.*}}, i8 0, i64 %[[SIZE]], i1 false), !annotation [[AUTO_INIT:!.+]]
 235 // PATTERN-LABEL: test_struct_vla(
 236 // PATTERN:  %vla.iszerosized = icmp eq i64 %{{.*}}, 0
 237 // PATTERN:  br i1 %vla.iszerosized, label %vla-init.cont, label %vla-setup.loop
 238 // PATTERN: vla-setup.loop:
 239 // PATTERN:  %[[SIZE:[0-9]+]] = mul nuw i64 %{{.*}}, 16
 240 // PATTERN:  %vla.end = getelementptr inbounds i8, ptr %vla, i64 %[[SIZE]]
 241 // PATTERN:  br label %vla-init.loop
 242 // PATTERN: vla-init.loop:
 243 // PATTERN:  %vla.cur = phi ptr [ %vla, %vla-setup.loop ], [ %vla.next, %vla-init.loop ]
 244 // PATTERN:  call void @llvm.memcpy{{.*}} %vla.cur, {{.*}}@__const.test_struct_vla.vla{{.*}}), !annotation [[AUTO_INIT:!.+]]
 245 // PATTERN:  %vla.next = getelementptr inbounds i8, ptr %vla.cur, i64 16
 246 // PATTERN:  %vla-init.isdone = icmp eq ptr %vla.next, %vla.end
 247 // PATTERN:  br i1 %vla-init.isdone, label %vla-init.cont, label %vla-init.loop
 248 // PATTERN: vla-init.cont:
 249 // PATTERN:  call void @{{.*}}used
 250 void test_struct_vla(int size) {
 251   // Same as above, but with a struct that doesn't just memcpy.
 252   struct {
 253     float f;
 254     char c;
 255     void *ptr;
 256   } vla[size];
 257   void *ptr = static_cast<void*>(vla);
 258   used(ptr);
 259 }
 260
 261 // UNINIT-LABEL:  test_zsa(
 262 // ZERO-LABEL:    test_zsa(
 263 // ZERO: %zsa = alloca [0 x i32], align 4
 264 // ZERO-NOT: %zsa
 265 // ZERO:  call void @{{.*}}used
 266 // PATTERN-LABEL: test_zsa(
 267 // PATTERN: %zsa = alloca [0 x i32], align 4
 268 // PATTERN-NOT: %zsa
 269 // PATTERN:  call void @{{.*}}used
 270 void test_zsa(int size) {
 271   // Technically not valid, but as long as clang accepts them we should do
 272   // something sensible (i.e. not store to the zero-size array).
 273   int zsa[0];
 274   used(zsa);
 275 }
 276
 277 // UNINIT-LABEL:  test_huge_uninit(
 278 // ZERO-LABEL:    test_huge_uninit(
 279 // ZERO: call void @llvm.memset{{.*}}, i8 0, i64 65536, {{.*}}), !annotation [[AUTO_INIT:!.+]]
 280 // PATTERN-LABEL: test_huge_uninit(
 281 // PATTERN: call void @llvm.memset{{.*}}, i8 -86, i64 65536, {{.*}}), !annotation [[AUTO_INIT:!.+]]
 282 void test_huge_uninit() {
 283   // We can't emit this as an inline constant to a store instruction because
 284   // SDNode hits an internal size limit.
 285   char big[65536];
 286   used(big);
 287 }
 288
 289 // UNINIT-LABEL:  test_huge_small_init(
 290 // ZERO-LABEL:    test_huge_small_init(
 291 // ZERO: call void @llvm.memset{{.*}}, i8 0, i64 65536,
 292 // ZERO-NOT: !annotation
 293 // ZERO: store i8 97,
 294 // ZERO: store i8 98,
 295 // ZERO: store i8 99,
 296 // ZERO: store i8 100,
 297 // PATTERN-LABEL: test_huge_small_init(
 298 // PATTERN: call void @llvm.memset{{.*}}, i8 0, i64 65536,
 299 // PATTERN-NOT: !annotation
 300 // PATTERN: store i8 97,
 301 // PATTERN: store i8 98,
 302 // PATTERN: store i8 99,
 303 // PATTERN: store i8 100,
 304 void test_huge_small_init() {
 305   char big[65536] = { 'a', 'b', 'c', 'd' };
 306   used(big);
 307 }
 308
 309 // UNINIT-LABEL:  test_huge_larger_init(
 310 // ZERO-LABEL:    test_huge_larger_init(
 311 // ZERO:  call void @llvm.memcpy{{.*}} @__const.test_huge_larger_init.big, i64 65536,
 312 // ZERO-NOT: !annotation
 313 // PATTERN-LABEL: test_huge_larger_init(
 314 // PATTERN:  call void @llvm.memcpy{{.*}} @__const.test_huge_larger_init.big, i64 65536,
 315 // PATTERN-NOT: !annotation
 316 void test_huge_larger_init() {
 317   char big[65536] = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
 318   used(big);
 319 }
 320
 321 } // extern "C"
 322
 323 // CHECK: [[AUTO_INIT]] = !{ !"auto-init" }