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rdmarsh2rdmarsh2
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Merge pull request #1237 from geoffw0/commentedoutcode2
CPP: Fix FPs from detecting commented out preprocessor logic
2 parents d8b47c8 + 2d15163 commit 09d0548

6 files changed

Lines changed: 132 additions & 9 deletions

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‎cpp/ql/src/Documentation/CommentedOutCode.qll‎

Lines changed: 39 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -47,12 +47,38 @@ private predicate looksLikeCode(string line) {
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)
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}
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/**
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* Holds if there is a preprocessor directive on the line indicated by
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* `f` and `line` that we permit code comments besides. For example this
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* is considered acceptable:
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* ```
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* #ifdef MYMACRO
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* ...
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* #endif // #ifdef MYMACRO
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* ```
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*/
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private predicate preprocLine(File f, int line) {
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exists(PreprocessorDirective pd, Location l |
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(
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pd instanceof PreprocessorElse or
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pd instanceof PreprocessorElif or
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pd instanceof PreprocessorEndif
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) and
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pd.getLocation() = l and
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l.getFile() = f and
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l.getStartLine() = line
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)
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}
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/**
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* The line of a C++-style comment within its file `f`.
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*/
5376
private int lineInFile(CppStyleComment c, File f) {
5477
f = c.getFile() and
55-
result = c.getLocation().getStartLine()
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result = c.getLocation().getStartLine() and
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// Ignore comments on the same line as a preprocessor directive.
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not preprocLine(f, result)
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}
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/**
@@ -89,9 +115,17 @@ private int commentId(CppStyleComment c, File f, int line) {
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*/
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class CommentBlock extends Comment {
91117
CommentBlock() {
92-
this instanceof CppStyleComment
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implies
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not exists(CppStyleComment pred, File f | lineInFile(pred, f) + 1 = lineInFile(this, f))
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(
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this instanceof CppStyleComment
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implies
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not exists(CppStyleComment pred, File f | lineInFile(pred, f) + 1 = lineInFile(this, f))
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) and (
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// Ignore comments on the same line as a preprocessor directive.
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not exists(Location l |
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l = this.getLocation() and
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preprocLine(l.getFile(), l.getStartLine())
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)
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)
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}
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97131
/**
@@ -133,6 +167,7 @@ class CommentBlock extends Comment {
133167

134168
predicate isCommentedOutCode() {
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not this.isDocumentation() and
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not this.getFile().(HeaderFile).noTopLevelCode() and
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this.numCodeLines().(float) / this.numLines().(float) > 0.5
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}
138173

‎cpp/ql/src/jsf/4.07 Header Files/AV Rule 35.ql‎

Lines changed: 1 addition & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -133,11 +133,7 @@ where not hf instanceof IncludeGuardedHeader
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// Exclude files which contain no declaration entries or top level
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// declarations (e.g. just preprocessor directives; or non-top level
135135
// code).
136-
and (
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exists(DeclarationEntry de | de.getFile() = hf) or
138-
exists(Declaration d | d.getFile() = hf and d.isTopLevel()) or
139-
exists(UsingEntry ue | ue.getFile() = hf)
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)
136+
and not hf.noTopLevelCode()
141137
// Exclude files which look like they contain 'x-macros'
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and not hasXMacro(hf)
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// Exclude files which are always #imported.

‎cpp/ql/src/semmle/code/cpp/File.qll‎

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -453,6 +453,20 @@ class HeaderFile extends File {
453453
exists(Include i | i.getIncludedFile() = this)
454454
}
455455

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/**
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* Holds if this header file does not contain any declaration entries or top level
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* declarations. For example it might be:
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* - a file containing only preprocessor directives and/or comments
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* - an empty file
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* - a file that contains non-top level code or data that's included in an
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* unusual way
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*/
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predicate noTopLevelCode()
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{
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not exists(DeclarationEntry de | de.getFile() = this) and
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not exists(Declaration d | d.getFile() = this and d.isTopLevel()) and
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not exists(UsingEntry ue | ue.getFile() = this)
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}
456470
}
457471

458472
/**

‎cpp/ql/test/query-tests/Documentation/CommentedOutCode/CommentedOutCode.expected‎

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -8,6 +8,11 @@
88
| test2.cpp:63:1:63:15 | // #pragma once | This comment appears to contain commented-out code |
99
| test2.cpp:65:1:65:17 | // # pragma once | This comment appears to contain commented-out code |
1010
| test2.cpp:67:1:67:19 | /*#error"myerror"*/ | This comment appears to contain commented-out code |
11+
| test2.cpp:91:1:95:2 | /*\n#ifdef MYMACRO\n\t// ...\n#endif // #ifdef MYMACRO\n*/ | This comment appears to contain commented-out code |
12+
| test2.cpp:107:21:107:43 | // #include "config2.h" | This comment appears to contain commented-out code |
13+
| test2.cpp:115:16:115:35 | /* #ifdef MYMACRO */ | This comment appears to contain commented-out code |
14+
| test2.cpp:117:1:117:24 | // commented_out_code(); | This comment appears to contain commented-out code |
15+
| test2.cpp:120:2:120:25 | // commented_out_code(); | This comment appears to contain commented-out code |
1116
| test.c:2:1:2:22 | // commented out code; | This comment appears to contain commented-out code |
1217
| test.c:4:1:7:8 | // some; | This comment appears to contain commented-out code |
1318
| test.c:9:1:13:8 | // also; | This comment appears to contain commented-out code |

‎cpp/ql/test/query-tests/Documentation/CommentedOutCode/config.h‎

Lines changed: 19 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,19 @@
1+
2+
/* define if you want setting 1 */
3+
#define SETTING1
4+
5+
// define if you want setting 2
6+
//#define SETTING2
7+
8+
/* define if you want setting 3 */
9+
//#define SETTING3
10+
11+
/* define if you want setting 4 */
12+
/* #define SETTING4 */
13+
14+
#if defined(SETTING3) && defined(SETTING4)
15+
#error "can't have both SETTING3 and SETTING4"
16+
#endif
17+
18+
/* uncomment if you don't want setting 5 */
19+
/* #undef SETTING5 */

‎cpp/ql/test/query-tests/Documentation/CommentedOutCode/test2.cpp‎

Lines changed: 54 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -65,3 +65,57 @@ void myFunction();
6565
// # pragma once
6666

6767
/*#error"myerror"*/
68+
69+
#ifdef MYMACRO
70+
71+
// ...
72+
73+
#endif // #ifdef MYMACRO
74+
75+
#if !defined(MYMACRO)
76+
77+
// ...
78+
79+
#else // #if !defined(MYMACRO)
80+
81+
// ...
82+
83+
#endif // #else #if !defined(MYMACRO)
84+
85+
#ifdef MYMACRO
86+
87+
// ...
88+
89+
#endif // #ifdef MYMACRO (comment)
90+
91+
/*
92+
#ifdef MYMACRO
93+
// ...
94+
#endif // #ifdef MYMACRO
95+
*/
96+
97+
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#ifdef MYMACRO1
99+
#ifdef MYMACRO2
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// ...
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103+
// comment at end of block
104+
#endif // #ifdef MYMACRO2
105+
#endif // #ifdef MYMACRO1
106+
107+
#include "config.h" // #include "config2.h"
108+
109+
#ifdef MYMACRO
110+
111+
// ...
112+
113+
#endif /* #ifdef MYMACRO */
114+
115+
#error "error" /* #ifdef MYMACRO */
116+
117+
// commented_out_code();
118+
119+
#if 0
120+
// commented_out_code();
121+
#endif

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