[PATCH] [StaticAnalyzer] Add 'clang_analyzer_warnIfReached'
Jared Grubb
jared.grubb at gmail.com
Mon Sep 30 20:40:08 PDT 2013
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.
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
>> }
>> }
>>
>>
>> _______________________________________________
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>> cfe-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>
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