Commit 0eba5dc8 authored by Artem Dergachev's avatar Artem Dergachev
Browse files

[analyzer] Fix modeling some library functions when UCHAR_MAX > INT_MAX. 

This makes life easier for downstream users who maintain exotic
target platforms.

Patch by Vince Bridgers!

Differential Revision: https://reviews.llvm.org/D75529
parent 54146cbd

clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp

+27 −15
Original line number Diff line number Diff line
@@ -510,8 +510,14 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( 
  const RangeInt LongMax = BVF.getMaxValue(LongTy).getLimitedValue();

  const RangeInt LongLongMax = BVF.getMaxValue(LongLongTy).getLimitedValue();



  const RangeInt UCharMax =

      BVF.getMaxValue(ACtx.UnsignedCharTy).getLimitedValue();

  // Set UCharRangeMax to min of int or uchar maximum value.

  // The C standard states that the arguments of functions like isalpha must

  // be representable as an unsigned char. Their type is 'int', so the max

  // value of the argument should be min(UCharMax, IntMax). This just happen

  // to be true for commonly used and well tested instruction set

  // architectures, but not for others.

  const RangeInt UCharRangeMax =

      std::min(BVF.getMaxValue(ACtx.UnsignedCharTy).getLimitedValue(), IntMax);



  // The platform dependent value of EOF.

  // Try our best to parse this from the Preprocessor, otherwise fallback to -1.
@@ -573,8 +579,8 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( 
  // Templates for summaries that are reused by many functions.

  auto Getc = [&]() {

    return Summary(ArgTypes{Irrelevant}, RetType{IntTy}, NoEvalCall)

        .Case(

            {ReturnValueCondition(WithinRange, {{EOFv, EOFv}, {0, UCharMax}})});

        .Case({ReturnValueCondition(WithinRange,

                                    {{EOFv, EOFv}, {0, UCharRangeMax}})});

  };

  auto Read = [&](RetType R, RangeInt Max) {

    return Summary(ArgTypes{Irrelevant, Irrelevant, SizeTy}, RetType{R},
@@ -609,12 +615,13 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( 
                  // The locale-specific range.

                  // No post-condition. We are completely unaware of

                  // locale-specific return values.

                  .Case({ArgumentCondition(0U, WithinRange, {{128, UCharMax}})})

                  .Case({ArgumentCondition(0U, WithinRange,

                                           {{128, UCharRangeMax}})})

                  .Case({ArgumentCondition(0U, OutOfRange,

                                           {{'0', '9'},

                                            {'A', 'Z'},

                                            {'a', 'z'},

                                            {128, UCharMax}}),

                                            {128, UCharRangeMax}}),

                         ReturnValueCondition(WithinRange, SingleValue(0))})},

      },

      {
@@ -625,10 +632,11 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( 
                                           {{'A', 'Z'}, {'a', 'z'}}),

                         ReturnValueCondition(OutOfRange, SingleValue(0))})

                  // The locale-specific range.

                  .Case({ArgumentCondition(0U, WithinRange, {{128, UCharMax}})})

                  .Case({ArgumentCondition(0U, WithinRange,

                                           {{128, UCharRangeMax}})})

                  .Case({ArgumentCondition(

                             0U, OutOfRange,

                             {{'A', 'Z'}, {'a', 'z'}, {128, UCharMax}}),

                             {{'A', 'Z'}, {'a', 'z'}, {128, UCharRangeMax}}),

                         ReturnValueCondition(WithinRange, SingleValue(0))})},

      },

      {
@@ -692,9 +700,11 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( 
                         ArgumentCondition(0U, OutOfRange, Range('a', 'z')),

                         ReturnValueCondition(WithinRange, SingleValue(0))})

                  // The locale-specific range.

                  .Case({ArgumentCondition(0U, WithinRange, {{128, UCharMax}})})

                  .Case({ArgumentCondition(0U, WithinRange,

                                           {{128, UCharRangeMax}})})

                  // Is not an unsigned char.

                  .Case({ArgumentCondition(0U, OutOfRange, Range(0, UCharMax)),

                  .Case({ArgumentCondition(0U, OutOfRange,

                                           Range(0, UCharRangeMax)),

                         ReturnValueCondition(WithinRange, SingleValue(0))})},

      },

      {
@@ -728,10 +738,11 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( 
                                           {{9, 13}, {' ', ' '}}),

                         ReturnValueCondition(OutOfRange, SingleValue(0))})

                  // The locale-specific range.

                  .Case({ArgumentCondition(0U, WithinRange, {{128, UCharMax}})})

                  .Case({ArgumentCondition(0U, WithinRange,

                                           {{128, UCharRangeMax}})})

                  .Case({ArgumentCondition(

                             0U, OutOfRange,

                             {{9, 13}, {' ', ' '}, {128, UCharMax}}),

                             {{9, 13}, {' ', ' '}, {128, UCharRangeMax}}),

                         ReturnValueCondition(WithinRange, SingleValue(0))})},

      },

      {
@@ -742,10 +753,11 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( 
                  .Case({ArgumentCondition(0U, WithinRange, Range('A', 'Z')),

                         ReturnValueCondition(OutOfRange, SingleValue(0))})

                  // The locale-specific range.

                  .Case({ArgumentCondition(0U, WithinRange, {{128, UCharMax}})})

                  .Case({ArgumentCondition(0U, WithinRange,

                                           {{128, UCharRangeMax}})})

                  // Other.

                  .Case({ArgumentCondition(0U, OutOfRange,

                                           {{'A', 'Z'}, {128, UCharMax}}),

                                           {{'A', 'Z'}, {128, UCharRangeMax}}),

                         ReturnValueCondition(WithinRange, SingleValue(0))})},

      },

      {
@@ -768,7 +780,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( 
      {"getchar",

       Summaries{Summary(ArgTypes{}, RetType{IntTy}, NoEvalCall)

                     .Case({ReturnValueCondition(

                         WithinRange, {{EOFv, EOFv}, {0, UCharMax}})})}},

                         WithinRange, {{EOFv, EOFv}, {0, UCharRangeMax}})})}},



      // read()-like functions that never return more than buffer size.

      // We are not sure how ssize_t is defined on every platform, so we