11 Commits

Author SHA1 Message Date
Mikhail R. Gadelha
81943b805b [analyzer] Fix Z3 backend after D48205
Summary:
An assertion was added in D48205 to catch places where a `nonloc::SymbolVal` was wrapping a `loc` object.

This patch fixes that in the Z3 backend by making the `SValBuilder` object accessible from inherited instances of `SimpleConstraintManager` and calling `SVB.makeSymbolVal(foo)` instead of `nonloc::SymbolVal(foo)`.

Reviewers: NoQ, george.karpenkov

Reviewed By: NoQ

Subscribers: xazax.hun, szepet, a.sidorin

Differential Revision: https://reviews.llvm.org/D49430

llvm-svn: 337304
2018-07-17 17:40:34 +00:00
Mikhail R. Gadelha
07f6e8e3a5 [analyzer] Fix the Z3 backend always generating unsigned APSInt
Summary:
In `toAPSInt`, the Z3 backend was not checking the variable `Int`'s type and was always generating unsigned `APSInt`s.

This was found by accident when I removed:
```
    llvm::APSInt ConvertedLHS, ConvertedRHS;
    QualType LTy, RTy;
    std::tie(ConvertedLHS, LTy) = fixAPSInt(*LHS);
    std::tie(ConvertedRHS, RTy) = fixAPSInt(*RHS);
-    doIntTypePromotion<llvm::APSInt, Z3ConstraintManager::castAPSInt>(
-        ConvertedLHS, LTy, ConvertedRHS, RTy);
    return BVF.evalAPSInt(BSE->getOpcode(), ConvertedLHS, ConvertedRHS);
```

And the `BasicValueFactory` started to complain about different `signedness`.

Reviewers: george.karpenkov, NoQ, ddcc

Reviewed By: ddcc

Subscribers: xazax.hun, szepet, a.sidorin

Differential Revision: https://reviews.llvm.org/D49305

llvm-svn: 337169
2018-07-16 13:32:22 +00:00
Mikhail R. Gadelha
53ac1a2ed4 [analyzer] Fix wrong comparison generation of the ranges generated by the refutation manager
The refutation manager is removing a true bug from the test in this patch.

The problem is that the following constraint:
```
(conj_$1{struct o *}) - (reg_$3<int * r>): [-9223372036854775808, 0]
```
is encoded as:
```
(and (bvuge (bvsub $1 $3) #x8000000000000000)
     (bvule (bvsub $1 $3) #x0000000000000000))
```
The issue is that unsigned comparisons (bvuge and bvule) are being generated instead of signed comparisons (bvsge and bvsle).

When generating the expressions:
```
(conj_$1{p *}) - (reg_$3<int * r>) >= -9223372036854775808
```
and
```
(conj_$1{p *}) - (reg_$3<int * r>) <= 0
```
both -9223372036854775808 and 0 are casted to pointer type and `LTy->isSignedIntegerOrEnumerationType()` in `Z3ConstraintManager::getZ3BinExpr` only checks if the type is signed, not if it's a pointer.

Reviewers: NoQ, george.karpenkov, ddcc

Subscribers: rnkovacs, NoQ, george.karpenkov, ddcc, xazax.hun, szepet, a.sidorin

Differential Revision: https://reviews.llvm.org/D48324

llvm-svn: 335926
2018-06-28 21:26:52 +00:00
Mikhail R. Gadelha
bd1077e2bc [analyzer] Optimize constraint generation when the range is a concrete value
Summary:
If a constraint is something like:
```
$0 = [1,1]
```
it'll now be created as:
```
assert($0 == 1)
```
instead of:
```
assert($0 >= 1 && $0 <= 1)
```

In general, ~3% speedup when solving per query in my machine. Biggest improvement was when verifying sqlite3, total time went down from 3000s to 2200s.

I couldn't create a test for this as there is no way to dump the formula yet. D48221 adds a method to dump the formula but there is no way to do it from the command line.

Also, a test that prints the formula will most likely fail in the future, as different solvers print the formula in different formats.

Reviewers: NoQ, george.karpenkov, ddcc

Reviewed By: george.karpenkov

Subscribers: xazax.hun, szepet, a.sidorin

Differential Revision: https://reviews.llvm.org/D48227

llvm-svn: 335116
2018-06-20 11:42:12 +00:00
Mikhail R. Gadelha
e7f703804d [analyzer] Add method to the generic SMT API to dump the SMT formula
Summary:
New method dump the SMT formula and the Z3 implementation.

There is no test because I only used it for debugging.

However, if requested, I can add an option to the static analyzer to dump the formula (whole program? per path?), maybe something like the trimmed graph but for SMT formulas.

Reviewers: NoQ, george.karpenkov, ddcc

Reviewed By: george.karpenkov

Subscribers: xazax.hun, szepet, a.sidorin

Differential Revision: https://reviews.llvm.org/D48221

llvm-svn: 334891
2018-06-16 14:36:17 +00:00
Vlad Tsyrklevich
6f8f15fa72 [Analyzer] Fix Z3ConstraintManager crash (PR37646)
Summary:
Fix another Z3ConstraintManager crash, use fixAPSInt() to extend a
boolean APSInt.

Reviewers: george.karpenkov, NoQ, ddcc

Reviewed By: george.karpenkov

Subscribers: xazax.hun, szepet, a.sidorin, cfe-commits

Differential Revision: https://reviews.llvm.org/D47617

llvm-svn: 334065
2018-06-06 06:09:02 +00:00
Mikhail R. Gadelha
735d8ea0d4 Created a tiny SMT interface and make Z3ConstraintManager implement it
Summary:
This patch implements a simple SMTConstraintManager API, and requires the implementation of two methods for now: `addRangeConstraints` and `isModelFeasible`.

Update Z3ConstraintManager to inherit it and implement required methods.

I also moved the method to dump the SMT formula from D45517 to this patch.

This patch was created based on the reviews from D47640.

Reviewers: george.karpenkov, NoQ, ddcc, dcoughlin

Reviewed By: george.karpenkov

Differential Revision: https://reviews.llvm.org/D47689

llvm-svn: 333899
2018-06-04 14:25:58 +00:00
Dominic Chen
cd81614e8b [analyzer] fix bug with 1-bit APSInt types in Z3ConstraintManager
Summary: Clang does not have a corresponding QualType for a 1-bit APSInt, so use the BoolTy and extend the APSInt. Split from D35450. Fixes PR37622.

Reviewers: george.karpenkov, NoQ

Subscribers: mikhail.ramalho, xazax.hun, szepet, rnkovacs, cfe-commits, a.sidorin

Differential Revision: https://reviews.llvm.org/D47603

llvm-svn: 333704
2018-05-31 22:23:07 +00:00
Dominic Chen
c0402c6916 Revert "[analyzer] Support generating and reasoning over more symbolic constraint types"
Assertion `Loc::isLocType(SSE->getLHS()->getType())' failed in Analysis/PR3991.m

This reverts commit e469ff2759275e67f9072b3d67fac90f647c0fe6.

llvm-svn: 307853
2017-07-12 21:43:42 +00:00
Dominic Chen
35610d21b2 [analyzer] Support generating and reasoning over more symbolic constraint types
Summary: Generate more IntSymExpr constraints, perform SVal simplification for IntSymExpr and SymbolCast constraints, and create fully symbolic SymExprs

Reviewers: zaks.anna, dcoughlin, NoQ, xazax.hun

Subscribers: mgorny, cfe-commits

Differential Revision: https://reviews.llvm.org/D28953

llvm-svn: 307833
2017-07-12 19:37:57 +00:00
Dominic Chen
08f943c563 [analyzer] Add new Z3 constraint manager backend
Summary: Implement new Z3 constraint manager backend.

Reviewers: zaks.anna, dcoughlin, NoQ, xazax.hun

Subscribers: mgorny, cfe-commits

Differential Revision: https://reviews.llvm.org/D28952

llvm-svn: 299463
2017-04-04 19:52:25 +00:00