[PATCH] [StaticAnalyzer] Add 'clang_analyzer_warnIfReached'
Anna Zaks
ganna at apple.com
Tue Oct 1 09:10:01 PDT 2013
I think the following would be the most consistent with the rest of the debug checkers:
- BugReport *R = new BugReport(*BT, "REACHABLE", N);
+ BugReport *R = new BugReport(*BT, "Analyzer reached this line (WARN-REACHED)", N);
Cheers,
Anna.
On Sep 30, 2013, at 8:40 PM, Jared Grubb <jared.grubb at gmail.com> wrote:
> Sorry for the delay. My free time has been limited lately.
>
> From your comments, the only change you suggested was the capitalization:
> - clang_analyzer_warnIfReached(); // expected-warning{{reached}}
> + clang_analyzer_warnIfReached(); // expected-warning{{REACHED}}
>
> Attached are the minor changes required to make that work. Unit tests continue to all pass.
>
> <patch-warnIfReached.diff>
>
>
> Jared
>
> On Sep 16, 2013, at 18:25, Jordan Rose <jordan_rose at apple.com> wrote:
>
>> [+Anna for opinions]
>>
>> Two comments:
>>
>> - I think we should keep the ExprInspection output in all caps, to make it clear that it's not a usual analyzer warning
>> - The null-pointer deref tests also halt analysis along that path. I don't think that's something we usually need to do, but there might be a few cases where it's important. We could probably just add a return in most cases, though.
>>
>> I think you're right that it's better to be explicit, even though it's functionally equivalent to constructs we have already. Anna?
>>
>> Jordan
>>
>>
>> On Sep 16, 2013, at 9:07 , Jared Grubb <jared.grubb at gmail.com> wrote:
>>
>>> While working on unit tests for a checker, I really wanted a facility to detect that the analyzer has (or has not) made certain branch choices.
>>>
>>> Looking through the unit test, this kind of check is done in various ways:
>>> * Intentional deref of null pointer (the most popular, apparently)
>>> * Intentional divide by zero (tests in "cast.c")
>>> * "clang_analyzer_eval(true); // expected-warning{{TRUE}}"
>>>
>>> Adding a new directive to explicitly serve this purpose helps the readability of unit tests. As proof of concept, I've modified an existing test to remove the fake null-pointer derefs.
>>>
>>> Unit tests continue to pass. The direct patch to the analyzer is very minimal.
>>>
>>> Jared
>>>
>>>
>>> diff --git a/docs/analyzer/DebugChecks.rst b/docs/analyzer/DebugChecks.rst
>>> index a0f2a07..b0983e8 100644
>>> --- a/docs/analyzer/DebugChecks.rst
>>> +++ b/docs/analyzer/DebugChecks.rst
>>> @@ -125,6 +125,19 @@ ExprInspection checks
>>> clang_analyzer_eval(value == 42); // expected-warning{{TRUE}}
>>> }
>>>
>>> +- void clang_analyzer_warnIfReached();
>>> +
>>> + Generate a warning if this line of code gets reached by the analyzer.
>>> +
>>> + Example usage::
>>> +
>>> + if (true) {
>>> + clang_analyzer_warnIfReached(); // expected-warning{{reached}}
>>> + }
>>> + else {
>>> + clang_analyzer_warnIfReached(); // no-warning
>>> + }
>>> +
>>>
>>> Statistics
>>> ==========
>>> diff --git a/lib/StaticAnalyzer/Checkers/ExprInspectionChecker.cpp b/lib/StaticAnalyzer/Checkers/ExprInspectionChecker.cpp
>>> index 9522d1d..53f7c3d 100644
>>> --- a/lib/StaticAnalyzer/Checkers/ExprInspectionChecker.cpp
>>> +++ b/lib/StaticAnalyzer/Checkers/ExprInspectionChecker.cpp
>>> @@ -22,6 +22,7 @@ class ExprInspectionChecker : public Checker< eval::Call > {
>>>
>>> void analyzerEval(const CallExpr *CE, CheckerContext &C) const;
>>> void analyzerCheckInlined(const CallExpr *CE, CheckerContext &C) const;
>>> + void analyzerWarnIfReached(const CallExpr *CE, CheckerContext &C) const;
>>> void analyzerCrash(const CallExpr *CE, CheckerContext &C) const;
>>>
>>> typedef void (ExprInspectionChecker::*FnCheck)(const CallExpr *,
>>> @@ -41,6 +42,7 @@ bool ExprInspectionChecker::evalCall(const CallExpr *CE,
>>> .Case("clang_analyzer_checkInlined",
>>> &ExprInspectionChecker::analyzerCheckInlined)
>>> .Case("clang_analyzer_crash", &ExprInspectionChecker::analyzerCrash)
>>> + .Case("clang_analyzer_warnIfReached", &ExprInspectionChecker::analyzerWarnIfReached)
>>> .Default(0);
>>>
>>> if (!Handler)
>>> @@ -99,6 +101,17 @@ void ExprInspectionChecker::analyzerEval(const CallExpr *CE,
>>> C.emitReport(R);
>>> }
>>>
>>> +void ExprInspectionChecker::analyzerWarnIfReached(const CallExpr *CE,
>>> + CheckerContext &C) const {
>>> + ExplodedNode *N = C.getPredecessor();
>>> +
>>> + if (!BT)
>>> + BT.reset(new BugType("Checking analyzer assumptions", "debug"));
>>> +
>>> + BugReport *R = new BugReport(*BT, "Analyzer reached this line", N);
>>> + C.emitReport(R);
>>> +}
>>> +
>>> void ExprInspectionChecker::analyzerCheckInlined(const CallExpr *CE,
>>> CheckerContext &C) const {
>>> ExplodedNode *N = C.getPredecessor();
>>> diff --git a/test/Analysis/misc-ps-region-store.cpp b/test/Analysis/misc-ps-region-store.cpp
>>> index 902a5e5..c00d357 100644
>>> --- a/test/Analysis/misc-ps-region-store.cpp
>>> +++ b/test/Analysis/misc-ps-region-store.cpp
>>> @@ -1,5 +1,7 @@
>>> -// RUN: %clang_cc1 -triple i386-apple-darwin9 -analyze -analyzer-checker=core,alpha.core -analyzer-store=region -verify -fblocks -analyzer-opt-analyze-nested-blocks %s -fexceptions -fcxx-exceptions
>>> -// RUN: %clang_cc1 -triple x86_64-apple-darwin9 -analyze -analyzer-checker=core,alpha.core -analyzer-store=region -verify -fblocks -analyzer-opt-analyze-nested-blocks %s -fexceptions -fcxx-exceptions
>>> +// RUN: %clang_cc1 -triple i386-apple-darwin9 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -analyzer-store=region -verify -fblocks -analyzer-opt-analyze-nested-blocks %s -fexceptions -fcxx-exceptions
>>> +// RUN: %clang_cc1 -triple x86_64-apple-darwin9 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -analyzer-store=region -verify -fblocks -analyzer-opt-analyze-nested-blocks %s -fexceptions -fcxx-exceptions
>>> +
>>> +void clang_analyzer_warnIfReached();
>>>
>>> // Test basic handling of references.
>>> char &test1_aux();
>>> @@ -54,9 +56,7 @@ int test_init_in_condition_switch() {
>>> if (x == 2)
>>> return 0;
>>> else {
>>> - // Unreachable.
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF; // no-warning
>>> + clang_analyzer_warnIfReached(); // unreachable
>>> }
>>> default:
>>> break;
>>> @@ -74,8 +74,7 @@ int test_init_in_condition_while() {
>>> if (z == 2)
>>> return 0;
>>>
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF; // no-warning
>>> + clang_analyzer_warnIfReached(); // unreachable
>>> return 0;
>>> }
>>>
>>> @@ -89,8 +88,7 @@ int test_init_in_condition_for() {
>>> if (z == 1)
>>> return 0;
>>>
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF; // no-warning
>>> + clang_analyzer_warnIfReached(); // unreachable
>>> return 0;
>>> }
>>>
>>> @@ -117,8 +115,7 @@ int TestHandleThis::null_deref_negative() {
>>> if (x == 10) {
>>> return 1;
>>> }
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF; // no-warning
>>> + clang_analyzer_warnIfReached(); // unreachable
>>> return 0;
>>> }
>>>
>>> @@ -127,8 +124,7 @@ int TestHandleThis::null_deref_positive() {
>>> if (x == 9) {
>>> return 1;
>>> }
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF; // expected-warning{{null pointer}}
>>> + clang_analyzer_warnIfReached(); // expected-warning{{reached}}
>>> return 0;
>>> }
>>>
>>> @@ -143,9 +139,9 @@ void pr7675_test() {
>>> pr7675(10);
>>> pr7675('c');
>>> pr7675_i(4.0i);
>>> - // Add null deref to ensure we are analyzing the code up to this point.
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF; // expected-warning{{null pointer}}
>>> +
>>> + // Add check to ensure we are analyzing the code up to this point.
>>> + clang_analyzer_warnIfReached(); // expected-warning{{reached}}
>>> }
>>>
>>> // <rdar://problem/8375510> - CFGBuilder should handle temporaries.
>>> @@ -328,26 +324,23 @@ class RDar9267815 {
>>> };
>>>
>>> void RDar9267815::test_pos() {
>>> - int *p = 0;
>>> if (x == 42)
>>> return;
>>> - *p = 0xDEADBEEF; // expected-warning {{null}}
>>> + clang_analyzer_warnIfReached(); // expected-warning{{reached}}
>>> }
>>> void RDar9267815::test() {
>>> - int *p = 0;
>>> if (x == 42)
>>> return;
>>> if (x == 42)
>>> - *p = 0xDEADBEEF; // no-warning
>>> + clang_analyzer_warnIfReached(); // no-warning
>>> }
>>>
>>> void RDar9267815::test2() {
>>> - int *p = 0;
>>> if (x == 42)
>>> return;
>>> invalidate();
>>> if (x == 42)
>>> - *p = 0xDEADBEEF; // expected-warning {{null}}
>>> + clang_analyzer_warnIfReached(); // expected-warning{{reached}}
>>> }
>>>
>>> // Test reference parameters.
>>> @@ -440,8 +433,7 @@ int rdar9948787_negative() {
>>> unsigned value = classWithStatic.value;
>>> if (value == 1)
>>> return 1;
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF; // no-warning
>>> + clang_analyzer_warnIfReached(); // no-warning
>>> return 0;
>>> }
>>>
>>> @@ -450,8 +442,7 @@ int rdar9948787_positive() {
>>> unsigned value = classWithStatic.value;
>>> if (value == 0)
>>> return 1;
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF; // expected-warning {{null}}
>>> + clang_analyzer_warnIfReached(); // expected-warning{{reached}}
>>> return 0;
>>> }
>>>
>>> @@ -467,8 +458,7 @@ void rdar10202899_test1() {
>>> void rdar10202899_test2() {
>>> if (val == rdar10202899_ValTA)
>>> return;
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF;
>>> + clang_analyzer_warnIfReached(); // no-warning
>>> }
>>>
>>> void rdar10202899_test3() {
>>> @@ -476,8 +466,7 @@ void rdar10202899_test3() {
>>> case rdar10202899_ValTA: return;
>>> default: ;
>>> };
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF;
>>> + clang_analyzer_warnIfReached(); // no-warning
>>> }
>>>
>>> // This used to crash the analyzer because of the unnamed bitfield.
>>> @@ -489,13 +478,12 @@ void PR11249()
>>> char f2[1];
>>> char f3;
>>> } V = { 1, {2}, 3 };
>>> - int *p = 0;
>>> if (V.f1 != 1)
>>> - *p = 0xDEADBEEF; // no-warning
>>> + clang_analyzer_warnIfReached(); // no-warning
>>> if (V.f2[0] != 2)
>>> - *p = 0xDEADBEEF; // no-warning
>>> + clang_analyzer_warnIfReached(); // no-warning
>>> if (V.f3 != 3)
>>> - *p = 0xDEADBEEF; // no-warning
>>> + clang_analyzer_warnIfReached(); // no-warning
>>> }
>>>
>>> // Handle doing a load from the memory associated with the code for
>>> @@ -599,12 +587,10 @@ void rdar10924675(unsigned short x[], int index, int index2) {
>>> void rdar11401827() {
>>> int x = int();
>>> if (!x) {
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF; // expected-warning {{null pointer}}
>>> + clang_analyzer_warnIfReached(); // expected-warning{{reached}}
>>> }
>>> else {
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF;
>>> + clang_analyzer_warnIfReached(); // no-warning
>>> }
>>> }
>>>
>>> @@ -701,8 +687,7 @@ const Rdar12755044_foo *radar12755044() {
>>> void rdar12759044() {
>>> int flag = 512;
>>> if (!(flag & 512)) {
>>> - int *p = 0;
>>> - *p = 0xDEADBEEF; // no-warning
>>> + clang_analyzer_warnIfReached(); // no-warning
>>> }
>>> }
>>>
>>>
>>> _______________________________________________
>>> cfe-commits mailing list
>>> cfe-commits at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>>
>
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