https://github.com/tbaederr created
https://github.com/llvm/llvm-project/pull/160118
Fixes #157492
>From 817af36fba48a42670afc91dc49a3ad748187363 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com>
Date: Tue, 16 Sep 2025 16:02:15 +0200
Subject: [PATCH] try evaluate string
---
clang/lib/AST/ByteCode/Context.cpp | 42 ++++++++++++++++++++++++++++++
clang/lib/AST/ByteCode/Context.h | 4 +++
clang/lib/AST/ExprConstant.cpp | 8 +++++-
3 files changed, 53 insertions(+), 1 deletion(-)
diff --git a/clang/lib/AST/ByteCode/Context.cpp
b/clang/lib/AST/ByteCode/Context.cpp
index cfda6e8ded760..fffdafe4b2e2f 100644
--- a/clang/lib/AST/ByteCode/Context.cpp
+++ b/clang/lib/AST/ByteCode/Context.cpp
@@ -236,6 +236,48 @@ bool Context::evaluateCharRange(State &Parent, const Expr
*SizeExpr,
return evaluateStringRepr(Parent, SizeExpr, PtrExpr, Result);
}
+bool Context::evaluateString(State &Parent, const Expr *E,
+ std::string &Result) {
+ assert(Stk.empty());
+ Compiler<EvalEmitter> C(*this, *P, Parent, Stk);
+
+ auto PtrRes = C.interpretAsPointer(E, [&](const Pointer &Ptr) {
+ const Descriptor *FieldDesc = Ptr.getFieldDesc();
+ if (!FieldDesc->isPrimitiveArray())
+ return false;
+
+ if (!Ptr.isConst())
+ return false;
+
+ unsigned N = Ptr.getNumElems();
+ if (Ptr.elemSize() == 1 /* bytes */) {
+ const char *Chars = reinterpret_cast<const char *>(Ptr.getRawAddress());
+ unsigned Length = strnlen(Chars, N);
+ Result.assign(Chars, Length);
+ return true;
+ }
+
+ PrimType ElemT = FieldDesc->getPrimType();
+ for (unsigned I = Ptr.getIndex(); I != N; ++I) {
+ INT_TYPE_SWITCH(ElemT, {
+ auto Elem = Ptr.elem<T>(I);
+ if (Elem.isZero())
+ return true;
+ Result.push_back(static_cast<char>(Elem));
+ });
+ }
+ // We didn't find a 0 byte.
+ return false;
+ });
+
+ if (PtrRes.isInvalid()) {
+ C.cleanup();
+ Stk.clear();
+ return false;
+ }
+ return true;
+}
+
bool Context::evaluateStrlen(State &Parent, const Expr *E, uint64_t &Result) {
assert(Stk.empty());
Compiler<EvalEmitter> C(*this, *P, Parent, Stk);
diff --git a/clang/lib/AST/ByteCode/Context.h b/clang/lib/AST/ByteCode/Context.h
index 280a31725555f..fadedf83e68ff 100644
--- a/clang/lib/AST/ByteCode/Context.h
+++ b/clang/lib/AST/ByteCode/Context.h
@@ -67,6 +67,10 @@ class Context final {
bool evaluateCharRange(State &Parent, const Expr *SizeExpr,
const Expr *PtrExpr, std::string &Result);
+ /// Evaluate \param E and if it can be evaluated to a sirint literal,
+ /// copy the result into \param Result.
+ bool evaluateString(State &Parent, const Expr *E, std::string &Result);
+
/// Evalute \param E and if it can be evaluated to a string literal,
/// run strlen() on it.
bool evaluateStrlen(State &Parent, const Expr *E, uint64_t &Result);
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 3b9ca82910033..e569263c9ab3c 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -18770,9 +18770,15 @@ std::optional<std::string>
Expr::tryEvaluateString(ASTContext &Ctx) const {
uint64_t Result;
std::string StringResult;
+ if (Info.EnableNewConstInterp) {
+ if (!Info.Ctx.getInterpContext().evaluateString(Info, this, StringResult))
+ return std::nullopt;
+ return StringResult;
+ }
+
if (EvaluateBuiltinStrLen(this, Result, Info, &StringResult))
return StringResult;
- return {};
+ return std::nullopt;
}
template <typename T>
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