clang/test/Analysis/uninit-asm-goto.cpp

   1 // RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -std=c++11 -Wuninitialized -verify %s
   2
   3 // test1: Expect no diagnostics
   4 int test1(int x) {
   5     int y;
   6     asm goto("" : "=r"(y) : "r"(x) : : err);
   7     return y;
   8   err:
   9     return -1;
  10 }
  11
  12 // test2: Expect no diagnostics
  13 int test2(int x) {
  14   int y;
  15   if (x < 42)
  16     asm goto("" : "+S"(x), "+D"(y) : "r"(x) :: indirect_1, indirect_2);
  17   else
  18     asm goto("" : "+S"(x), "+D"(y) : "r"(x), "r"(y) :: indirect_1, indirect_2);
  19   return x + y;
  20 indirect_1:
  21   return -42;
  22 indirect_2:
  23   return y;
  24 }
  25
  26 // test3: Expect no diagnostics
  27 int test3(int x) {
  28   int y;
  29   asm goto("" : "=&r"(y) : "r"(x) : : fail);
  30 normal:
  31   y += x;
  32   return y;
  33   if (x) {
  34 fail:
  35     return y;
  36   }
  37   return 0;
  38 }
  39
  40 // test4: Expect no diagnostics
  41 int test4(int x) {
  42   int y;
  43   goto forward;
  44 backward:
  45   return y;
  46 forward:
  47   asm goto("" : "=r"(y) : "r"(x) : : backward);
  48   return y;
  49 }
  50
  51 // test5: Expect no diagnostics
  52 int test5(int x) {
  53   int y;
  54   asm goto("" : "+S"(x), "+D"(y) : "r"(x) :: indirect, fallthrough);
  55 fallthrough:
  56   return y;
  57 indirect:
  58   return -2;
  59 }
  60
  61 // test6: Expect no diagnostics.
  62 int test6(unsigned int *x) {
  63   unsigned int val;
  64
  65   // See through casts and unary operators.
  66   asm goto("" : "=r" (*(unsigned int *)(&val)) ::: indirect);
  67   *x = val;
  68   return 0;
  69 indirect:
  70   return -1;
  71 }
  72
  73 // test7: Expect no diagnostics.
  74 int test7(int z) {
  75     int x;
  76     if (z)
  77       asm goto ("":"=r"(x):::A1,A2);
  78     return 0;
  79     A1:
  80     A2:
  81     return x;
  82 }
  83
  84 // test8: Expect no diagnostics
  85 int test8() {
  86     int x = 0;
  87     asm goto ("":"=r"(x):::A1,A2);
  88     return 0;
  89     A1:
  90     A2:
  91     return x;
  92 }
  93
  94 // test9: Expect no diagnostics
  95 int test9 (int x) {
  96     int y;
  97     asm goto("": "=r"(y) :::out);
  98     return 42;
  99 out:
 100     return y;
 101 }
 102
 103 int test10() {
 104   int y; // expected-note {{initialize the variable 'y' to silence this warning}}
 105   asm goto(""::::out);
 106   return 42;
 107 out:
 108   return y; // expected-warning {{variable 'y' is uninitialized when used here}}
 109 }