[clang][Interp] Fix array subscript eval order #101804
Merged
+41
−12
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Always evaluate LHS first, then RHS.
llvmbot
added
clang
|
@llvm/pr-subscribers-clang Author: Timm Baeder (tbaederr) ChangesAlways evaluate LHS first, then RHS. Full diff: https://github.com/llvm/llvm-project/pull/101804.diff 4 Files Affected:
diff --git a/clang/lib/AST/Interp/Compiler.cpp b/clang/lib/AST/Interp/Compiler.cpp
index f600d9b5b80f8..e1fa0eb1eacb3 100644
--- a/clang/lib/AST/Interp/Compiler.cpp
+++ b/clang/lib/AST/Interp/Compiler.cpp
@@ -1282,21 +1282,31 @@ bool Compiler<Emitter>::VisitImplicitValueInitExpr(
template <class Emitter>
bool Compiler<Emitter>::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
- const Expr *Base = E->getBase();
+ const Expr *LHS = E->getLHS();
+ const Expr *RHS = E->getRHS();
const Expr *Index = E->getIdx();
if (DiscardResult)
- return this->discard(Base) && this->discard(Index);
+ return this->discard(LHS) && this->discard(RHS);
- // Take pointer of LHS, add offset from RHS.
- // What's left on the stack after this is a pointer.
- if (!this->visit(Base))
- return false;
+ // C++17's rules require us to evaluate the LHS first, regardless of which
+ // side is the base.
+ bool Success = true;
+ for (const Expr *SubExpr : {LHS, RHS}) {
+ if (!this->visit(SubExpr))
+ Success = false;
+ }
- if (!this->visit(Index))
+ if (!Success)
return false;
PrimType IndexT = classifyPrim(Index->getType());
+ // If the index is first, we need to change that.
+ if (LHS == Index) {
+ if (!this->emitFlip(PT_Ptr, IndexT, E))
+ return false;
+ }
+
return this->emitArrayElemPtrPop(IndexT, E);
}
diff --git a/clang/lib/AST/Interp/Interp.h b/clang/lib/AST/Interp/Interp.h
index b54635b9988e2..a3f81e2de466b 100644
--- a/clang/lib/AST/Interp/Interp.h
+++ b/clang/lib/AST/Interp/Interp.h
@@ -1158,6 +1158,21 @@ bool Pop(InterpState &S, CodePtr OpPC) {
return true;
}
+/// [Value1, Value2] -> [Value2, Value1]
+template <PrimType TopName, PrimType BottomName>
+bool Flip(InterpState &S, CodePtr OpPC) {
+ using TopT = typename PrimConv<TopName>::T;
+ using BottomT = typename PrimConv<BottomName>::T;
+
+ const auto &Top = S.Stk.pop<TopT>();
+ const auto &Bottom = S.Stk.pop<BottomT>();
+
+ S.Stk.push<TopT>(Top);
+ S.Stk.push<BottomT>(Bottom);
+
+ return true;
+}
+
//===----------------------------------------------------------------------===//
// Const
//===----------------------------------------------------------------------===//
diff --git a/clang/lib/AST/Interp/Opcodes.td b/clang/lib/AST/Interp/Opcodes.td
index 3e830f89754dc..70d06bdfdc21c 100644
--- a/clang/lib/AST/Interp/Opcodes.td
+++ b/clang/lib/AST/Interp/Opcodes.td
@@ -729,6 +729,11 @@ def Dup : Opcode {
let HasGroup = 1;
}
+def Flip : Opcode {
+ let Types = [AllTypeClass, AllTypeClass];
+ let HasGroup = 1;
+}
+
// [] -> []
def Invalid : Opcode {}
def Unsupported : Opcode {}
diff --git a/clang/test/AST/Interp/eval-order.cpp b/clang/test/AST/Interp/eval-order.cpp
index 7a7ce6a714601..77f50831f4f47 100644
--- a/clang/test/AST/Interp/eval-order.cpp
+++ b/clang/test/AST/Interp/eval-order.cpp
@@ -45,7 +45,7 @@ namespace EvalOrder {
}
template <typename T> constexpr T &&b(T &&v) {
if (!done_a)
- throw "wrong"; // expected-note 7{{not valid}}
+ throw "wrong"; // expected-note 5{{not valid}}
done_b = true;
return (T &&)v;
}
@@ -95,10 +95,9 @@ namespace EvalOrder {
constexpr int arr[3] = {};
SEQ(A(arr)[B(0)]);
SEQ(A(+arr)[B(0)]);
- SEQ(A(0)[B(arr)]); // expected-error {{not an integral constant expression}} FIXME \
- // expected-note 2{{in call to}}
- SEQ(A(0)[B(+arr)]); // expected-error {{not an integral constant expression}} FIXME \
- // expected-note 2{{in call to}}
+ SEQ(A(0)[B(arr)]);
+ SEQ(A(0)[B(+arr)]);
+
SEQ(A(ud)[B(0)]);
// Rule 7: a << b
|
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/107/builds/1553 Here is the relevant piece of the build log for the reference: |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/143/builds/1236 Here is the relevant piece of the build log for the reference: |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Always evaluate LHS first, then RHS.