https://github.com/tbaederr created
https://github.com/llvm/llvm-project/pull/147550
Instead, return the new Pointer. This was weird before because some callers had
to get the value from the stack again to perform further operations.
>From e0dc4095477f345470a37e3b826385822448078e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com>
Date: Tue, 8 Jul 2025 10:53:39 +0200
Subject: [PATCH] [clang][bytecode][NFC] Don't push anything in OffsetHelper
Instead, return the new Pointer. This was weird before because some
callers had to get the value from the stack again to perform further
operations.
---
clang/lib/AST/ByteCode/Interp.h | 105 ++++++++++++++++++--------------
1 file changed, 60 insertions(+), 45 deletions(-)
diff --git a/clang/lib/AST/ByteCode/Interp.h b/clang/lib/AST/ByteCode/Interp.h
index 85a07abb5ed01..9d17f96c97c85 100644
--- a/clang/lib/AST/ByteCode/Interp.h
+++ b/clang/lib/AST/ByteCode/Interp.h
@@ -2066,34 +2066,32 @@ inline bool CastMemberPtrPtr(InterpState &S, CodePtr
OpPC) {
//===----------------------------------------------------------------------===//
template <class T, ArithOp Op>
-bool OffsetHelper(InterpState &S, CodePtr OpPC, const T &Offset,
- const Pointer &Ptr, bool IsPointerArith = false) {
+std::optional<Pointer> OffsetHelper(InterpState &S, CodePtr OpPC,
+ const T &Offset, const Pointer &Ptr,
+ bool IsPointerArith = false) {
// A zero offset does not change the pointer.
- if (Offset.isZero()) {
- S.Stk.push<Pointer>(Ptr);
- return true;
- }
+ if (Offset.isZero())
+ return Ptr;
if (IsPointerArith && !CheckNull(S, OpPC, Ptr, CSK_ArrayIndex)) {
// The CheckNull will have emitted a note already, but we only
// abort in C++, since this is fine in C.
if (S.getLangOpts().CPlusPlus)
- return false;
+ return std::nullopt;
}
// Arrays of unknown bounds cannot have pointers into them.
if (!CheckArray(S, OpPC, Ptr))
- return false;
+ return std::nullopt;
// This is much simpler for integral pointers, so handle them first.
if (Ptr.isIntegralPointer()) {
uint64_t V = Ptr.getIntegerRepresentation();
uint64_t O = static_cast<uint64_t>(Offset) * Ptr.elemSize();
if constexpr (Op == ArithOp::Add)
- S.Stk.push<Pointer>(V + O, Ptr.asIntPointer().Desc);
+ return Pointer(V + O, Ptr.asIntPointer().Desc);
else
- S.Stk.push<Pointer>(V - O, Ptr.asIntPointer().Desc);
- return true;
+ return Pointer(V - O, Ptr.asIntPointer().Desc);
} else if (Ptr.isFunctionPointer()) {
uint64_t O = static_cast<uint64_t>(Offset);
uint64_t N;
@@ -2105,8 +2103,7 @@ bool OffsetHelper(InterpState &S, CodePtr OpPC, const T
&Offset,
if (N > 1)
S.CCEDiag(S.Current->getSource(OpPC), diag::note_constexpr_array_index)
<< N << /*non-array*/ true << 0;
- S.Stk.push<Pointer>(Ptr.asFunctionPointer().getFunction(), N);
- return true;
+ return Pointer(Ptr.asFunctionPointer().getFunction(), N);
}
assert(Ptr.isBlockPointer());
@@ -2156,7 +2153,7 @@ bool OffsetHelper(InterpState &S, CodePtr OpPC, const T
&Offset,
}
if (Invalid && S.getLangOpts().CPlusPlus)
- return false;
+ return std::nullopt;
// Offset is valid - compute it on unsigned.
int64_t WideIndex = static_cast<int64_t>(Index);
@@ -2172,15 +2169,11 @@ bool OffsetHelper(InterpState &S, CodePtr OpPC, const T
&Offset,
// we don't get here.
if (Result == 0 && Ptr.isOnePastEnd()) {
if (Ptr.getFieldDesc()->isArray())
- S.Stk.push<Pointer>(Ptr.atIndex(0));
- else
- S.Stk.push<Pointer>(Ptr.asBlockPointer().Pointee,
- Ptr.asBlockPointer().Base);
- return true;
+ return Ptr.atIndex(0);
+ return Pointer(Ptr.asBlockPointer().Pointee, Ptr.asBlockPointer().Base);
}
- S.Stk.push<Pointer>(Ptr.atIndex(static_cast<uint64_t>(Result)));
- return true;
+ return Ptr.atIndex(static_cast<uint64_t>(Result));
}
template <PrimType Name, class T = typename PrimConv<Name>::T>
@@ -2189,16 +2182,26 @@ bool AddOffset(InterpState &S, CodePtr OpPC) {
Pointer Ptr = S.Stk.pop<Pointer>();
if (Ptr.isBlockPointer())
Ptr = Ptr.expand();
- return OffsetHelper<T, ArithOp::Add>(S, OpPC, Offset, Ptr,
- /*IsPointerArith=*/true);
+
+ if (std::optional<Pointer> Result = OffsetHelper<T, ArithOp::Add>(
+ S, OpPC, Offset, Ptr, /*IsPointerArith=*/true)) {
+ S.Stk.push<Pointer>(*Result);
+ return true;
+ }
+ return false;
}
template <PrimType Name, class T = typename PrimConv<Name>::T>
bool SubOffset(InterpState &S, CodePtr OpPC) {
const T &Offset = S.Stk.pop<T>();
const Pointer &Ptr = S.Stk.pop<Pointer>();
- return OffsetHelper<T, ArithOp::Sub>(S, OpPC, Offset, Ptr,
- /*IsPointerArith=*/true);
+
+ if (std::optional<Pointer> Result = OffsetHelper<T, ArithOp::Sub>(
+ S, OpPC, Offset, Ptr, /*IsPointerArith=*/true)) {
+ S.Stk.push<Pointer>(*Result);
+ return true;
+ }
+ return false;
}
template <ArithOp Op>
@@ -2218,12 +2221,13 @@ static inline bool IncDecPtrHelper(InterpState &S,
CodePtr OpPC,
// Now the current Ptr again and a constant 1.
OneT One = OneT::from(1);
- if (!OffsetHelper<OneT, Op>(S, OpPC, One, P, /*IsPointerArith=*/true))
- return false;
-
- // Store the new value.
- Ptr.deref<Pointer>() = S.Stk.pop<Pointer>();
- return true;
+ if (std::optional<Pointer> Result =
+ OffsetHelper<OneT, Op>(S, OpPC, One, P, /*IsPointerArith=*/true)) {
+ // Store the new value.
+ Ptr.deref<Pointer>() = *Result;
+ return true;
+ }
+ return false;
}
static inline bool IncPtr(InterpState &S, CodePtr OpPC) {
@@ -2925,16 +2929,22 @@ inline bool ArrayElemPtr(InterpState &S, CodePtr OpPC) {
if (Offset.isZero()) {
if (Ptr.getFieldDesc()->isArray() && Ptr.getIndex() == 0) {
- S.Stk.push<Pointer>(Ptr.atIndex(0));
- } else {
- S.Stk.push<Pointer>(Ptr);
+ S.Stk.push<Pointer>(Ptr.atIndex(0).narrow());
+ return true;
}
- } else {
- if (!OffsetHelper<T, ArithOp::Add>(S, OpPC, Offset, Ptr))
- return false;
+ S.Stk.push<Pointer>(Ptr);
+ return true;
+ }
+
+ assert(!Offset.isZero());
+
+ if (std::optional<Pointer> Result =
+ OffsetHelper<T, ArithOp::Add>(S, OpPC, Offset, Ptr)) {
+ S.Stk.push<Pointer>(Result->narrow());
+ return true;
}
- return NarrowPtr(S, OpPC);
+ return false;
}
template <PrimType Name, class T = typename PrimConv<Name>::T>
@@ -2949,16 +2959,21 @@ inline bool ArrayElemPtrPop(InterpState &S, CodePtr
OpPC) {
if (Offset.isZero()) {
if (Ptr.getFieldDesc()->isArray() && Ptr.getIndex() == 0) {
- S.Stk.push<Pointer>(Ptr.atIndex(0));
- } else {
- S.Stk.push<Pointer>(Ptr);
+ S.Stk.push<Pointer>(Ptr.atIndex(0).narrow());
+ return true;
}
- } else {
- if (!OffsetHelper<T, ArithOp::Add>(S, OpPC, Offset, Ptr))
- return false;
+ S.Stk.push<Pointer>(Ptr);
+ return true;
}
- return NarrowPtr(S, OpPC);
+ assert(!Offset.isZero());
+
+ if (std::optional<Pointer> Result =
+ OffsetHelper<T, ArithOp::Add>(S, OpPC, Offset, Ptr)) {
+ S.Stk.push<Pointer>(Result->narrow());
+ return true;
+ }
+ return false;
}
template <PrimType Name, class T = typename PrimConv<Name>::T>
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