[clang] [clang][bytecode] Handle builtin_wmemcmp (PR #120070)
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Mon Dec 16 04:04:29 PST 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Timm Baeder (tbaederr)
<details>
<summary>Changes</summary>
---
Full diff: https://github.com/llvm/llvm-project/pull/120070.diff
2 Files Affected:
- (modified) clang/lib/AST/ByteCode/InterpBuiltin.cpp (+49-22)
- (modified) clang/test/AST/ByteCode/builtin-functions.cpp (+15)
``````````diff
diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
index c1c43672176add..d6b33c8aeeaac3 100644
--- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp
+++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
@@ -1917,7 +1917,8 @@ static bool interp__builtin_memcmp(InterpState &S, CodePtr OpPC,
const APSInt &Size =
peekToAPSInt(S.Stk, *S.getContext().classify(Call->getArg(2)));
- if (ID == Builtin::BImemcmp || ID == Builtin::BIbcmp)
+ if (ID == Builtin::BImemcmp || ID == Builtin::BIbcmp ||
+ ID == Builtin::BIwmemcmp)
diagnoseNonConstexprBuiltin(S, OpPC, ID);
if (Size.isZero()) {
@@ -1925,14 +1926,18 @@ static bool interp__builtin_memcmp(InterpState &S, CodePtr OpPC,
return true;
}
+ bool IsWide =
+ (ID == Builtin::BIwmemcmp || ID == Builtin::BI__builtin_wmemcmp);
+
+ const ASTContext &ASTCtx = S.getASTContext();
// FIXME: This is an arbitrary limitation the current constant interpreter
// had. We could remove this.
- if (!isOneByteCharacterType(PtrA.getType()) ||
- !isOneByteCharacterType(PtrB.getType())) {
+ if (!IsWide && (!isOneByteCharacterType(PtrA.getType()) ||
+ !isOneByteCharacterType(PtrB.getType()))) {
S.FFDiag(S.Current->getSource(OpPC),
diag::note_constexpr_memcmp_unsupported)
- << ("'" + S.getASTContext().BuiltinInfo.getName(ID) + "'").str()
- << PtrA.getType() << PtrB.getType();
+ << ("'" + ASTCtx.BuiltinInfo.getName(ID) + "'").str() << PtrA.getType()
+ << PtrB.getType();
return false;
}
@@ -1941,42 +1946,62 @@ static bool interp__builtin_memcmp(InterpState &S, CodePtr OpPC,
// Now, read both pointers to a buffer and compare those.
BitcastBuffer BufferA(
- Bits(S.getASTContext().getTypeSize(PtrA.getFieldDesc()->getType())));
+ Bits(ASTCtx.getTypeSize(PtrA.getFieldDesc()->getType())));
readPointerToBuffer(S.getContext(), PtrA, BufferA, false);
// FIXME: The swapping here is UNDOING something we do when reading the
// data into the buffer.
- if (S.getASTContext().getTargetInfo().isBigEndian())
+ if (ASTCtx.getTargetInfo().isBigEndian())
swapBytes(BufferA.Data.get(), BufferA.byteSize().getQuantity());
BitcastBuffer BufferB(
- Bits(S.getASTContext().getTypeSize(PtrB.getFieldDesc()->getType())));
+ Bits(ASTCtx.getTypeSize(PtrB.getFieldDesc()->getType())));
readPointerToBuffer(S.getContext(), PtrB, BufferB, false);
// FIXME: The swapping here is UNDOING something we do when reading the
// data into the buffer.
- if (S.getASTContext().getTargetInfo().isBigEndian())
+ if (ASTCtx.getTargetInfo().isBigEndian())
swapBytes(BufferB.Data.get(), BufferB.byteSize().getQuantity());
size_t MinBufferSize = std::min(BufferA.byteSize().getQuantity(),
BufferB.byteSize().getQuantity());
- size_t CmpSize =
- std::min(MinBufferSize, static_cast<size_t>(Size.getZExtValue()));
-
- for (size_t I = 0; I != CmpSize; ++I) {
- std::byte A = BufferA.Data[I];
- std::byte B = BufferB.Data[I];
- if (A < B) {
- pushInteger(S, -1, Call->getType());
- return true;
- } else if (A > B) {
- pushInteger(S, 1, Call->getType());
- return true;
+ unsigned ElemSize = 1;
+ if (IsWide)
+ ElemSize = ASTCtx.getTypeSizeInChars(ASTCtx.getWCharType()).getQuantity();
+ // The Size given for the wide variants is in wide-char units. Convert it
+ // to bytes.
+ size_t ByteSize = Size.getZExtValue() * ElemSize;
+ size_t CmpSize = std::min(MinBufferSize, ByteSize);
+
+ for (size_t I = 0; I != CmpSize; I += ElemSize) {
+ if (IsWide) {
+ INT_TYPE_SWITCH(*S.getContext().classify(ASTCtx.getWCharType()), {
+ T A = *reinterpret_cast<T *>(BufferA.Data.get() + I);
+ T B = *reinterpret_cast<T *>(BufferB.Data.get() + I);
+ if (A < B) {
+ pushInteger(S, -1, Call->getType());
+ return true;
+ } else if (A > B) {
+ pushInteger(S, 1, Call->getType());
+ return true;
+ }
+ });
+ } else {
+ std::byte A = BufferA.Data[I];
+ std::byte B = BufferB.Data[I];
+
+ if (A < B) {
+ pushInteger(S, -1, Call->getType());
+ return true;
+ } else if (A > B) {
+ pushInteger(S, 1, Call->getType());
+ return true;
+ }
}
}
// We compared CmpSize bytes above. If the limiting factor was the Size
// passed, we're done and the result is equality (0).
- if (Size.getZExtValue() <= CmpSize) {
+ if (ByteSize <= CmpSize) {
pushInteger(S, 0, Call->getType());
return true;
}
@@ -2467,6 +2492,8 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
case Builtin::BImemcmp:
case Builtin::BI__builtin_bcmp:
case Builtin::BIbcmp:
+ case Builtin::BI__builtin_wmemcmp:
+ case Builtin::BIwmemcmp:
if (!interp__builtin_memcmp(S, OpPC, Frame, F, Call))
return false;
break;
diff --git a/clang/test/AST/ByteCode/builtin-functions.cpp b/clang/test/AST/ByteCode/builtin-functions.cpp
index 4ee24646286fa8..5906cb970f06c4 100644
--- a/clang/test/AST/ByteCode/builtin-functions.cpp
+++ b/clang/test/AST/ByteCode/builtin-functions.cpp
@@ -1270,4 +1270,19 @@ namespace Memcmp {
static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 7) != 0);
static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 6) != 0);
static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 5) == 0);
+
+
+ static_assert(__builtin_wmemcmp(L"abaa", L"abba", 3) == -1);
+ static_assert(__builtin_wmemcmp(L"abaa", L"abba", 2) == 0);
+ static_assert(__builtin_wmemcmp(0, 0, 0) == 0);
+#if __WCHAR_WIDTH__ == 32
+ static_assert(__builtin_wmemcmp(L"a\x83838383", L"aa", 2) ==
+ (wchar_t)-1U >> 31);
+#endif
+ static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0banana", 100) == 0); // both-error {{not an integral constant}} \
+ // both-note {{dereferenced one-past-the-end}}
+ static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 100) == -1); // FIXME: Should we reject this?
+ static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 7) == -1);
+ static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 6) == -1);
+ static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 5) == 0);
}
``````````
</details>
https://github.com/llvm/llvm-project/pull/120070
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