Commit 76819754 authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r354937: 

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r354937 | joerg | 2019-02-27 01:40:59 +0100 (Wed, 27 Feb 2019) | 9 lines

Fix inline assembler constraint validation

The current constraint logic is both too lax and too strict. It fails
for input outside the [INT_MIN..INT_MAX] range, but it also implicitly
accepts 0 as value when it should not. Adjust logic to handle both
correctly.

Differential Revision: https://reviews.llvm.org/D58649

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llvm-svn: 355673
parent 0a0560be

clang/include/clang/Basic/TargetInfo.h

+6 −4
Original line number Diff line number Diff line
@@ -807,6 +807,7 @@ public: 
    struct {

      int Min;

      int Max;

      bool isConstrained;

    } ImmRange;

    llvm::SmallSet<int, 4> ImmSet;
@@ -817,6 +818,7 @@ public: 
        : Flags(0), TiedOperand(-1), ConstraintStr(ConstraintStr.str()),

          Name(Name.str()) {

      ImmRange.Min = ImmRange.Max = 0;

      ImmRange.isConstrained = false;

    }



    const std::string &getConstraintStr() const { return ConstraintStr; }
@@ -845,8 +847,9 @@ public: 
      return (Flags & CI_ImmediateConstant) != 0;

    }

    bool isValidAsmImmediate(const llvm::APInt &Value) const {

      return (Value.sge(ImmRange.Min) && Value.sle(ImmRange.Max)) ||

             ImmSet.count(Value.getZExtValue()) != 0;

      if (!ImmSet.empty())

        return ImmSet.count(Value.getZExtValue()) != 0;

      return !ImmRange.isConstrained || (Value.sge(ImmRange.Min) && Value.sle(ImmRange.Max));

    }



    void setIsReadWrite() { Flags |= CI_ReadWrite; }
@@ -858,6 +861,7 @@ public: 
      Flags |= CI_ImmediateConstant;

      ImmRange.Min = Min;

      ImmRange.Max = Max;

      ImmRange.isConstrained = true;

    }

    void setRequiresImmediate(llvm::ArrayRef<int> Exacts) {

      Flags |= CI_ImmediateConstant;
@@ -870,8 +874,6 @@ public: 
    }

    void setRequiresImmediate() {

      Flags |= CI_ImmediateConstant;

      ImmRange.Min = INT_MIN;

      ImmRange.Max = INT_MAX;

    }



    /// Indicate that this is an input operand that is tied to

clang/test/Sema/inline-asm-validate-x86.c

+4 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ void K(int i, int j) { 
void L(int i, int j) {

  static const int Invalid1 = 1;

  static const int Invalid2 = 42;

  static const int Invalid3 = 0;

  static const int Valid1 = 0xff;

  static const int Valid2 = 0xffff;

  static const int Valid3 = 0xffffffff;
@@ -67,6 +68,9 @@ void L(int i, int j) { 
  __asm__("xorl %0,%2"

          : "=r"(i)

          : "0"(i), "L"(Invalid2)); // expected-error{{value '42' out of range for constraint 'L'}}

  __asm__("xorl %0,%2"

          : "=r"(i)

          : "0"(i), "L"(Invalid3)); // expected-error{{value '0' out of range for constraint 'L'}}

  __asm__("xorl %0,%2"

          : "=r"(i)

          : "0"(i), "L"(Valid1)); // expected-no-error