xref: /llvm-project/clang/test/Analysis/uninit-asm-goto.cpp (revision af6656338db365fde6c0b0e53db8f98aa8ed59d4) 
1 // RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -std=c++11 -Wuninitialized -verify %s
2 
3 // test1: Expect no diagnostics
test1(int x)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
test2(int x)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
test3(int x)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
test4(int x)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
test5(int x)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.
test6(unsigned int * x)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.
test7(int z)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
test8()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
test9(int x)95 int test9 (int x) {
96     int y;
97     asm goto("": "=r"(y) :::out);
98     return 42;
99 out:
100     return y;
101 }
102 
test10()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 }
110