dead-stores.c revision 632d1ece2715b1c8a0c99e1b8b487f4c148c89d5
1d427023c334fe03105d9359711a3df4d6f23b344Daniel Dunbar// RUN: clang -analyze -warn-dead-stores -verify %s && 29457a800f1fea4db4bb595c77de277609913b1b3Ted Kremenek// RUN: clang -analyze -checker-simple -analyzer-store=basic -analyzer-constraints=basic -warn-dead-stores -verify %s && 39457a800f1fea4db4bb595c77de277609913b1b3Ted Kremenek// RUN: clang -analyze -checker-simple -analyzer-store=basic -analyzer-constraints=range -warn-dead-stores -verify %s && 49457a800f1fea4db4bb595c77de277609913b1b3Ted Kremenek// RUN: clang -analyze -checker-cfref -analyzer-store=basic -analyzer-constraints=basic -warn-dead-stores -verify %s && 59457a800f1fea4db4bb595c77de277609913b1b3Ted Kremenek// RUN: clang -analyze -checker-cfref -analyzer-store=basic -analyzer-constraints=range -warn-dead-stores -verify %s && 69457a800f1fea4db4bb595c77de277609913b1b3Ted Kremenek// RUN: clang -analyze -checker-cfref -analyzer-store=region -analyzer-constraints=basic -warn-dead-stores -verify %s && 79457a800f1fea4db4bb595c77de277609913b1b3Ted Kremenek// RUN: clang -analyze -checker-cfref -analyzer-store=region -analyzer-constraints=range -warn-dead-stores -verify %s 88aefcbfd3c0409c26ca44c123a41edd631eab9bcTed Kremenek 949a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenekvoid f1() { 10aa395ba050c558b1ebf66c7868165938d98b6a5bTed Kremenek int k, y; 110fdf06e5eef80ce56ce6499ba662453919b95af1Ted Kremenek int abc=1; 121a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek long idx=abc+3*5; // expected-warning {{never read}} 13aa395ba050c558b1ebf66c7868165938d98b6a5bTed Kremenek} 148aefcbfd3c0409c26ca44c123a41edd631eab9bcTed Kremenek 1549a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenekvoid f2(void *b) { 168aefcbfd3c0409c26ca44c123a41edd631eab9bcTed Kremenek char *c = (char*)b; // no-warning 171a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek char *d = b+1; // expected-warning {{never read}} 18a316e7b735b12ce6b34961a9dcfaae34f4b08d29Douglas Gregor printf("%s", c); // expected-warning{{implicitly declaring C library function 'printf' with type 'int (char const *, ...)'}} \ 19a316e7b735b12ce6b34961a9dcfaae34f4b08d29Douglas Gregor // expected-note{{please include the header <stdio.h> or explicitly provide a declaration for 'printf'}} 208aefcbfd3c0409c26ca44c123a41edd631eab9bcTed Kremenek} 2174c43a0967d07572dd6907776d91cdb2b2e7179aTed Kremenek 2249a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenekvoid f3() { 230fdf06e5eef80ce56ce6499ba662453919b95af1Ted Kremenek int r; 240fdf06e5eef80ce56ce6499ba662453919b95af1Ted Kremenek if ((r = f()) != 0) { // no-warning 250fdf06e5eef80ce56ce6499ba662453919b95af1Ted Kremenek int y = r; // no-warning 260fdf06e5eef80ce56ce6499ba662453919b95af1Ted Kremenek printf("the error is: %d\n", y); 270fdf06e5eef80ce56ce6499ba662453919b95af1Ted Kremenek } 2874c43a0967d07572dd6907776d91cdb2b2e7179aTed Kremenek} 2949a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenek 3049a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenekvoid f4(int k) { 3149a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenek 3249a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenek k = 1; 3349a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenek 3449a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenek if (k) 3549a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenek f1(); 3649a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenek 371a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek k = 2; // expected-warning {{never read}} 3849a2fd2758996b6f674babf19c75b3d01e77e2d4Ted Kremenek} 39f87821c086a46411883b385c743996a35cc8e154Ted Kremenek 40f87821c086a46411883b385c743996a35cc8e154Ted Kremenekvoid f5() { 41f87821c086a46411883b385c743996a35cc8e154Ted Kremenek 42f87821c086a46411883b385c743996a35cc8e154Ted Kremenek int x = 4; // no-warning 431a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek int *p = &x; // expected-warning{{never read}} 44f87821c086a46411883b385c743996a35cc8e154Ted Kremenek 45a23157e6b9e2388edebd3d383dd7acfab6a4c0c0Ted Kremenek} 46a23157e6b9e2388edebd3d383dd7acfab6a4c0c0Ted Kremenek 47a23157e6b9e2388edebd3d383dd7acfab6a4c0c0Ted Kremenekint f6() { 48a23157e6b9e2388edebd3d383dd7acfab6a4c0c0Ted Kremenek 49a23157e6b9e2388edebd3d383dd7acfab6a4c0c0Ted Kremenek int x = 4; 501a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek ++x; // expected-warning{{never read}} 51a23157e6b9e2388edebd3d383dd7acfab6a4c0c0Ted Kremenek return 1; 52a23157e6b9e2388edebd3d383dd7acfab6a4c0c0Ted Kremenek} 531a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek 541a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenekint f7(int *p) { 551a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek // This is allowed for defensive programming. 561a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek p = 0; // no-warning 571a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek return 1; 581a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek} 591a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek 601a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenekint f8(int *p) { 614489fe10fa073eb326e2c8906db170f009050911Daniel Dunbar extern int *baz(); 621a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek if (p = baz()) // expected-warning{{Although the value}} 631a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek return 1; 641a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek return 0; 651a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek} 661a654b60ef40e84f3943cdb581795c4d4dae1e45Ted Kremenek 672cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenekint f9() { 682cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek int x = 4; 692cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek x = x + 10; // expected-warning{{never read}} 702cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek return 1; 712cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek} 722cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek 732cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenekint f10() { 742cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek int x = 4; 752cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek x = 10 + x; // expected-warning{{never read}} 762cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek return 1; 772cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek} 782cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek 798b00b6e80dbeb04dd919699f7818344dd4cbaad9Ted Kremenekint f11() { 808b00b6e80dbeb04dd919699f7818344dd4cbaad9Ted Kremenek int x = 4; 81380277e46ec1d2d9abedcddf357ceea935cbe576Ted Kremenek return x++; // expected-warning{{never read}} 828b00b6e80dbeb04dd919699f7818344dd4cbaad9Ted Kremenek} 838b00b6e80dbeb04dd919699f7818344dd4cbaad9Ted Kremenek 84380277e46ec1d2d9abedcddf357ceea935cbe576Ted Kremenekint f11b() { 85380277e46ec1d2d9abedcddf357ceea935cbe576Ted Kremenek int x = 4; 867f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek return ((((++x)))); // no-warning 87380277e46ec1d2d9abedcddf357ceea935cbe576Ted Kremenek} 88380277e46ec1d2d9abedcddf357ceea935cbe576Ted Kremenek 89fc7ff5540412f8003024e1b4940fb8408dff2ca6Ted Kremenekint f12a(int y) { 90fc7ff5540412f8003024e1b4940fb8408dff2ca6Ted Kremenek int x = y; // expected-warning{{never read}} 91fc7ff5540412f8003024e1b4940fb8408dff2ca6Ted Kremenek return 1; 92fc7ff5540412f8003024e1b4940fb8408dff2ca6Ted Kremenek} 93fc7ff5540412f8003024e1b4940fb8408dff2ca6Ted Kremenekint f12b(int y) { 94fc7ff5540412f8003024e1b4940fb8408dff2ca6Ted Kremenek int x __attribute__((unused)) = y; // no-warning 95fc7ff5540412f8003024e1b4940fb8408dff2ca6Ted Kremenek return 1; 96fc7ff5540412f8003024e1b4940fb8408dff2ca6Ted Kremenek} 972cfac226b028e5a2165af077268f70cd2ab4b1a8Ted Kremenek 98efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek// Filed with PR 2630. This code should produce no warnings. 99efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenekint f13(void) 100efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek{ 101efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek int a = 1; 102efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek int b, c = b = a + a; 103efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek 104efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek if (b > 0) 105efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek return (0); 106efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek 107efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek return (a + b + c); 108efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek} 109efe88f5776b42ec2defb8ba29269a6c3683e9485Ted Kremenek 110b497ebdce35c708e902db2d49183925a612b4914Ted Kremenek// Filed with PR 2763. 11184fa6b90abf73e8cc539c9947ed5a6286f588569Ted Kremenekint f14(int count) { 112b497ebdce35c708e902db2d49183925a612b4914Ted Kremenek int index, nextLineIndex; 113b497ebdce35c708e902db2d49183925a612b4914Ted Kremenek for (index = 0; index < count; index = nextLineIndex+1) { 114b497ebdce35c708e902db2d49183925a612b4914Ted Kremenek nextLineIndex = index+1; // no-warning 115b497ebdce35c708e902db2d49183925a612b4914Ted Kremenek continue; 116b497ebdce35c708e902db2d49183925a612b4914Ted Kremenek } 117b497ebdce35c708e902db2d49183925a612b4914Ted Kremenek return index; 118b497ebdce35c708e902db2d49183925a612b4914Ted Kremenek} 11984fa6b90abf73e8cc539c9947ed5a6286f588569Ted Kremenek 12084fa6b90abf73e8cc539c9947ed5a6286f588569Ted Kremenek// Test case for <rdar://problem/6248086> 12184fa6b90abf73e8cc539c9947ed5a6286f588569Ted Kremenekvoid f15(unsigned x, unsigned y) { 12284fa6b90abf73e8cc539c9947ed5a6286f588569Ted Kremenek int count = x * y; // no-warning 12384fa6b90abf73e8cc539c9947ed5a6286f588569Ted Kremenek int z[count]; 12484fa6b90abf73e8cc539c9947ed5a6286f588569Ted Kremenek} 12584fa6b90abf73e8cc539c9947ed5a6286f588569Ted Kremenek 126610a09e409bea151a42dd907768f1e0c4b103f1fTed Kremenekint f16(int x) { 127610a09e409bea151a42dd907768f1e0c4b103f1fTed Kremenek x = x * 2; 128d2025e26738c3017af6685e342a3a746cdf8249fTed Kremenek x = sizeof(int [x = (x || x + 1) * 2]) // expected-warning{{Although the value stored to 'x' is used}} 129d2025e26738c3017af6685e342a3a746cdf8249fTed Kremenek ? 5 : 8; 130610a09e409bea151a42dd907768f1e0c4b103f1fTed Kremenek return x; 131610a09e409bea151a42dd907768f1e0c4b103f1fTed Kremenek} 132610a09e409bea151a42dd907768f1e0c4b103f1fTed Kremenek 1333b58786f85aaa173e122f6eaff0b6efa233d59a2Ted Kremenek// Self-assignments should not be flagged as dead stores. 1343b58786f85aaa173e122f6eaff0b6efa233d59a2Ted Kremenekint f17() { 1353b58786f85aaa173e122f6eaff0b6efa233d59a2Ted Kremenek int x = 1; 1363b58786f85aaa173e122f6eaff0b6efa233d59a2Ted Kremenek x = x; // no-warning 1373b58786f85aaa173e122f6eaff0b6efa233d59a2Ted Kremenek} 1387f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek 1397f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek// <rdar://problem/6506065> 1407f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek// The values of dead stores are only "consumed" in an enclosing expression 1417f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek// what that value is actually used. In other words, don't say "Although the value stored to 'x' is used...". 1427f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenekint f18() { 1437f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek int x = 0; // no-warning 1447f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek if (1) 1457f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek x = 10; // expected-warning{{Value stored to 'x' is never read}} 1467f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek while (1) 1477f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek x = 10; // expected-warning{{Value stored to 'x' is never read}} 1487f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek do 1497f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek x = 10; // expected-warning{{Value stored to 'x' is never read}} 1507f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek while (1); 1517f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek 1527f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek return (x = 10); // expected-warning{{Although the value stored to 'x' is used in the enclosing expression, the value is never actually read from 'x'}} 1537f5fce7200fdbf03f7d70134a57271e584fcb766Ted Kremenek} 154d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek 155d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek// PR 3514: false positive `dead initialization` warning for init to global 156d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek// http://llvm.org/bugs/show_bug.cgi?id=3514 157d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenekextern const int MyConstant; 158d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenekint f19(void) { 159d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek int x = MyConstant; // no-warning 160d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek x = 1; 161d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek return x; 162d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek} 163d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek 164d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenekint f19b(void) { // FIXME: Should this case be considered the same as f19? 165d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek const int MyConstant = 0; 166d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek int x = MyConstant; // expected-warning{{never read}} 167d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek x = 1; 168d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek return x; 169d3098ee64c069a3eff4d2d0a5d655d968c7b5dd2Ted Kremenek} 170632d1ece2715b1c8a0c99e1b8b487f4c148c89d5Ted Kremenek 171632d1ece2715b1c8a0c99e1b8b487f4c148c89d5Ted Kremenekvoid f20(void) { 172632d1ece2715b1c8a0c99e1b8b487f4c148c89d5Ted Kremenek int x = 1; // no-warning 173632d1ece2715b1c8a0c99e1b8b487f4c148c89d5Ted Kremenek#pragma unused(x) 174632d1ece2715b1c8a0c99e1b8b487f4c148c89d5Ted Kremenek} 175632d1ece2715b1c8a0c99e1b8b487f4c148c89d5Ted Kremenek 176