https://github.com/tbaederr created
https://github.com/llvm/llvm-project/pull/116999
This looks a little ugly now, I should wait for #116843.
>From c316394e5948539beadd62aab71566a42b76a760 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com>
Date: Wed, 20 Nov 2024 17:14:01 +0100
Subject: [PATCH] [clang][bytecode] Fix bitcasting from null pointers
This looks a little ugly now, I should wait for #116843.
---
clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp | 14 ++++++++++++--
clang/test/AST/ByteCode/builtin-bit-cast.cpp | 2 ++
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp
b/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp
index 7e8853d3469317..a5de8c3f6dcae3 100644
--- a/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp
+++ b/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp
@@ -299,6 +299,9 @@ static bool readPointerToBuffer(const Context &Ctx, const
Pointer &FromPtr,
llvm::sys::IsLittleEndianHost);
bool BigEndianTarget = ASTCtx.getTargetInfo().isBigEndian();
+ uint64_t PointerSizeInBits =
+ ASTCtx.getTargetInfo().getPointerWidth(LangAS::Default);
+
return enumeratePointerFields(
FromPtr, Ctx,
[&](const Pointer &P, PrimType T, size_t BitOffset,
@@ -310,8 +313,15 @@ static bool readPointerToBuffer(const Context &Ctx, const
Pointer &FromPtr,
assert(P.isInitialized());
// nullptr_t is a PT_Ptr for us, but it's still not std::is_pointer_v.
- if (T == PT_Ptr)
- assert(false && "Implement casting to pointer types");
+ if (T == PT_Ptr) {
+ assert(P.getType()->isNullPtrType());
+ std::byte Zeroes[] = {std::byte{0}, std::byte{0}, std::byte{0},
+ std::byte{0}, std::byte{0}, std::byte{0},
+ std::byte{0}, std::byte{0}};
+ assert(PointerSizeInBits <= (8 * 8));
+ Buffer.pushData(Zeroes, PointerSizeInBits, BigEndianTarget);
+ return true;
+ }
CharUnits ObjectReprChars = ASTCtx.getTypeSizeInChars(P.getType());
unsigned BitWidth = ASTCtx.toBits(ObjectReprChars);
diff --git a/clang/test/AST/ByteCode/builtin-bit-cast.cpp
b/clang/test/AST/ByteCode/builtin-bit-cast.cpp
index 60e8c3a615c5e6..fbaff4ba226d58 100644
--- a/clang/test/AST/ByteCode/builtin-bit-cast.cpp
+++ b/clang/test/AST/ByteCode/builtin-bit-cast.cpp
@@ -135,6 +135,8 @@ namespace simple {
/// diagnoses it.
static_assert(__builtin_bit_cast(intptr_t, nullptr) == 0); // ref-error
{{not an integral constant expression}} \
// ref-note
{{indeterminate value can only initialize an object}}
+
+ constexpr int test_from_nullptr_pass = (__builtin_bit_cast(unsigned char[8],
nullptr), 0);
}
namespace Fail {
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