[clang][bytecode] Don't set OnePastEnd bit for array elements #136422
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If we refer to arr[N], don't set the OnePastEnd bit of the APValue, since that is already encoded in the array index.
llvmbot
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@llvm/pr-subscribers-clang Author: Timm Baeder (tbaederr) ChangesIf we refer to arr[N], don't set the OnePastEnd bit of the APValue, since that is already encoded in the array index. Full diff: https://github.com/llvm/llvm-project/pull/136422.diff 2 Files Affected:
diff --git a/clang/lib/AST/ByteCode/Pointer.cpp b/clang/lib/AST/ByteCode/Pointer.cpp
index 686ec381d232a..059503cae3561 100644
--- a/clang/lib/AST/ByteCode/Pointer.cpp
+++ b/clang/lib/AST/ByteCode/Pointer.cpp
@@ -223,6 +223,7 @@ APValue Pointer::toAPValue(const ASTContext &ASTCtx) const {
UsePath = false;
// Build the path into the object.
+ bool OnePastEnd = isOnePastEnd();
Pointer Ptr = *this;
while (Ptr.isField() || Ptr.isArrayElement()) {
@@ -251,9 +252,10 @@ APValue Pointer::toAPValue(const ASTContext &ASTCtx) const {
Ptr = Ptr.expand();
const Descriptor *Desc = Ptr.getFieldDesc();
unsigned Index;
- if (Ptr.isOnePastEnd())
+ if (Ptr.isOnePastEnd()) {
Index = Ptr.getArray().getNumElems();
- else
+ OnePastEnd = false;
+ } else
Index = Ptr.getIndex();
QualType ElemType = Desc->getElemQualType();
@@ -304,8 +306,7 @@ APValue Pointer::toAPValue(const ASTContext &ASTCtx) const {
std::reverse(Path.begin(), Path.end());
if (UsePath)
- return APValue(Base, Offset, Path,
- /*IsOnePastEnd=*/!isElementPastEnd() && isOnePastEnd());
+ return APValue(Base, Offset, Path, OnePastEnd);
return APValue(Base, Offset, APValue::NoLValuePath());
}
diff --git a/clang/test/AST/ByteCode/arrays.cpp b/clang/test/AST/ByteCode/arrays.cpp
index e50839e0f0877..934c3a3e7aff1 100644
--- a/clang/test/AST/ByteCode/arrays.cpp
+++ b/clang/test/AST/ByteCode/arrays.cpp
@@ -761,3 +761,13 @@ namespace PointerSubscript {
struct S{};
static_assert((foo<S>(), true));
}
+
+namespace OnePastEndDiag {
+
+ constexpr int a(const int *b) {
+ return *b; // both-note {{read of dereferenced one-past-the-end pointer}}
+ }
+ constexpr int foo[] = {1,2};
+ constexpr int k = a(foo + 2); // both-error {{must be initialized by a constant expression}} \
+ // both-note {{in call to 'a(&foo[2])'}}
+}
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cor3ntin
approved these changes
Apr 19, 2025
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/199/builds/2873 Here is the relevant piece of the build log for the reference |
hnrklssn
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Apr 24, 2025
Update clang/test/AST/ByteCode/cxx20.cpp to align with the new behaviour in 6196b4e (llvm#136422).
IanWood1
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to IanWood1/llvm-project
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May 6, 2025
…36422) If we refer to arr[N], don't set the OnePastEnd bit of the APValue, since that is already encoded in the array index.
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If we refer to arr[N], don't set the OnePastEnd bit of the APValue, since that is already encoded in the array index.