llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Timm Baeder (tbaederr) <details> <summary>Changes</summary> Unfortunately, a few circumstances make the implementation here less than ideal, but we need to handle overlapping regions anyway. --- Full diff: https://github.com/llvm/llvm-project/pull/132523.diff 2 Files Affected: - (modified) clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp (+29-12) - (modified) clang/test/AST/ByteCode/builtin-functions.cpp (+1-2) ``````````diff diff --git a/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp b/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp index 6b8860c09167c..239b3104e89f1 100644 --- a/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp +++ b/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp @@ -19,6 +19,8 @@ #include "clang/AST/RecordLayout.h" #include "clang/Basic/TargetInfo.h" +#include <variant> + using namespace clang; using namespace clang::interp; @@ -450,33 +452,48 @@ bool clang::interp::DoBitCastPtr(InterpState &S, CodePtr OpPC, return Success; } +using PrimTypeVariant = + std::variant<Pointer, FunctionPointer, MemberPointer, FixedPoint, + Integral<8, false>, Integral<8, true>, Integral<16, false>, + Integral<16, true>, Integral<32, false>, Integral<32, true>, + Integral<64, false>, Integral<64, true>, IntegralAP<true>, + IntegralAP<false>, Boolean, Floating>; + +// NB: This implementation isn't exactly ideal, but: +// 1) We can't just do a bitcast here since we need to be able to +// copy pointers. +// 2) This also needs to handle overlapping regions. +// 3) We currently have no way of iterating over the fields of a pointer +// backwards. bool clang::interp::DoMemcpy(InterpState &S, CodePtr OpPC, const Pointer &SrcPtr, const Pointer &DestPtr, Bits Size) { assert(SrcPtr.isBlockPointer()); assert(DestPtr.isBlockPointer()); - unsigned SrcStartOffset = SrcPtr.getByteOffset(); - unsigned DestStartOffset = DestPtr.getByteOffset(); - + llvm::SmallVector<PrimTypeVariant> Values; enumeratePointerFields(SrcPtr, S.getContext(), Size, [&](const Pointer &P, PrimType T, Bits BitOffset, Bits FullBitWidth, bool PackedBools) -> bool { - unsigned SrcOffsetDiff = - P.getByteOffset() - SrcStartOffset; - - Pointer DestP = - Pointer(DestPtr.asBlockPointer().Pointee, - DestPtr.asBlockPointer().Base, - DestStartOffset + SrcOffsetDiff); + TYPE_SWITCH(T, { Values.push_back(P.deref<T>()); }); + return true; + }); + unsigned ValueIndex = 0; + enumeratePointerFields(DestPtr, S.getContext(), Size, + [&](const Pointer &P, PrimType T, Bits BitOffset, + Bits FullBitWidth, bool PackedBools) -> bool { TYPE_SWITCH(T, { - DestP.deref<T>() = P.deref<T>(); - DestP.initialize(); + P.deref<T>() = std::get<T>(Values[ValueIndex]); + P.initialize(); }); + ++ValueIndex; return true; }); + // We should've read all the values into DestPtr. + assert(ValueIndex == Values.size()); + return true; } diff --git a/clang/test/AST/ByteCode/builtin-functions.cpp b/clang/test/AST/ByteCode/builtin-functions.cpp index 3dd348031fec1..13a34f71a6354 100644 --- a/clang/test/AST/ByteCode/builtin-functions.cpp +++ b/clang/test/AST/ByteCode/builtin-functions.cpp @@ -1276,7 +1276,6 @@ namespace BuiltinMemcpy { static_assert(test_incomplete_array_type() == 1234); // both-error {{constant}} both-note {{in call}} - /// FIXME: memmove needs to support overlapping memory regions. constexpr bool memmoveOverlapping() { char s1[] {1, 2, 3}; __builtin_memmove(s1, s1 + 1, 2 * sizeof(char)); @@ -1289,7 +1288,7 @@ namespace BuiltinMemcpy { return Result1 && Result2; } - static_assert(memmoveOverlapping()); // expected-error {{failed}} + static_assert(memmoveOverlapping()); } namespace Memcmp { `````````` </details> https://github.com/llvm/llvm-project/pull/132523 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
