r354937 - Fix inline assembler constraint validation

[Hans Wennborg via cfe-commits]

Merged to release_80 in r355673.

On Wed, Feb 27, 2019 at 1:40 AM Joerg Sonnenberger via cfe-commits
<cfe-commits at lists.llvm.org> wrote:
>
> Author: joerg
> Date: Tue Feb 26 16:40:59 2019
> New Revision: 354937
>
> URL: http://llvm.org/viewvc/llvm-project?rev=354937&view=rev
> Log:
> 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
>
> Modified:
>     cfe/trunk/include/clang/Basic/TargetInfo.h
>     cfe/trunk/test/Sema/inline-asm-validate-x86.c
>
> Modified: cfe/trunk/include/clang/Basic/TargetInfo.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/TargetInfo.h?rev=354937&r1=354936&r2=354937&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/TargetInfo.h (original)
> +++ cfe/trunk/include/clang/Basic/TargetInfo.h Tue Feb 26 16:40:59 2019
> @@ -816,6 +816,7 @@ public:
>      struct {
>        int Min;
>        int Max;
> +      bool isConstrained;
>      } ImmRange;
>      llvm::SmallSet<int, 4> ImmSet;
>
> @@ -826,6 +827,7 @@ 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; }
> @@ -854,8 +856,9 @@ 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; }
> @@ -867,6 +870,7 @@ public:
>        Flags |= CI_ImmediateConstant;
>        ImmRange.Min = Min;
>        ImmRange.Max = Max;
> +      ImmRange.isConstrained = true;
>      }
>      void setRequiresImmediate(llvm::ArrayRef<int> Exacts) {
>        Flags |= CI_ImmediateConstant;
> @@ -879,8 +883,6 @@ 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
>
> Modified: cfe/trunk/test/Sema/inline-asm-validate-x86.c
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/inline-asm-validate-x86.c?rev=354937&r1=354936&r2=354937&view=diff
> ==============================================================================
> --- cfe/trunk/test/Sema/inline-asm-validate-x86.c (original)
> +++ cfe/trunk/test/Sema/inline-asm-validate-x86.c Tue Feb 26 16:40:59 2019
> @@ -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;
> @@ -69,6 +70,9 @@ void L(int i, int j) {
>            : "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
>    __asm__("xorl %0,%2"
>            : "=r"(i)
>
>
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