Timm =?utf-8?q?Bäder?= <tbae...@redhat.com> Message-ID: <llvm.org/llvm/llvm-project/pull/149...@github.com> In-Reply-To:
https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/149677 None >From 9db49be1f605ec039b984bd7df3e29c127df1866 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com> Date: Sat, 19 Jul 2025 23:02:13 +0200 Subject: [PATCH 1/2] [clang][bytecode] Use in Expr::tryEvaluateStrLen() --- clang/lib/AST/ByteCode/Context.cpp | 32 +++++++++++++++++++++++++++ clang/lib/AST/ByteCode/Context.h | 4 ++++ clang/lib/AST/ExprConstant.cpp | 4 ++++ clang/test/Sema/warn-fortify-source.c | 5 +++++ 4 files changed, 45 insertions(+) diff --git a/clang/lib/AST/ByteCode/Context.cpp b/clang/lib/AST/ByteCode/Context.cpp index ead6e4af5d403..ebb809a33c1fc 100644 --- a/clang/lib/AST/ByteCode/Context.cpp +++ b/clang/lib/AST/ByteCode/Context.cpp @@ -235,6 +235,38 @@ bool Context::evaluateCharRange(State &Parent, const Expr *SizeExpr, return evaluateStringRepr(Parent, SizeExpr, PtrExpr, Result); } +bool Context::evaluateStrlen(State &Parent, const Expr *E, uint64_t &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; + + unsigned N = Ptr.getNumElems(); + PrimType ElemT = FieldDesc->getPrimType(); + Result = 0; + for (unsigned I = Ptr.getIndex(); I != N; ++I) { + INT_TYPE_SWITCH(ElemT, { + auto Elem = Ptr.atIndex(I).deref<T>(); + if (Elem.isZero()) + return true; + ++Result; + }); + } + // We didn't find a 0 byte. + return false; + }); + + if (PtrRes.isInvalid()) { + C.cleanup(); + Stk.clear(); + return false; + } + return true; +} + const LangOptions &Context::getLangOpts() const { return Ctx.getLangOpts(); } static PrimType integralTypeToPrimTypeS(unsigned BitWidth) { diff --git a/clang/lib/AST/ByteCode/Context.h b/clang/lib/AST/ByteCode/Context.h index acf750421f8af..6065d3e53f230 100644 --- a/clang/lib/AST/ByteCode/Context.h +++ b/clang/lib/AST/ByteCode/Context.h @@ -66,6 +66,10 @@ class Context final { bool evaluateCharRange(State &Parent, const Expr *SizeExpr, const Expr *PtrExpr, 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); + /// Returns the AST context. ASTContext &getASTContext() const { return Ctx; } /// Returns the language options. diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index e57540511a9de..0d12161756467 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -18184,6 +18184,10 @@ bool Expr::EvaluateCharRangeAsString(APValue &Result, bool Expr::tryEvaluateStrLen(uint64_t &Result, ASTContext &Ctx) const { Expr::EvalStatus Status; EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold); + + if (Info.EnableNewConstInterp) + return Info.Ctx.getInterpContext().evaluateStrlen(Info, this, Result); + return EvaluateBuiltinStrLen(this, Result, Info); } diff --git a/clang/test/Sema/warn-fortify-source.c b/clang/test/Sema/warn-fortify-source.c index f48ea0907c657..216878c0836d8 100644 --- a/clang/test/Sema/warn-fortify-source.c +++ b/clang/test/Sema/warn-fortify-source.c @@ -3,6 +3,11 @@ // RUN: %clang_cc1 -xc++ -triple x86_64-apple-macosx10.14.0 %s -verify // RUN: %clang_cc1 -xc++ -triple x86_64-apple-macosx10.14.0 %s -verify -DUSE_BUILTINS +// RUN: %clang_cc1 -triple x86_64-apple-macosx10.14.0 %s -verify -fexperimental-new-constant-interpreter +// RUN: %clang_cc1 -triple x86_64-apple-macosx10.14.0 %s -verify -DUSE_BUILTINS -fexperimental-new-constant-interpreter +// RUN: %clang_cc1 -xc++ -triple x86_64-apple-macosx10.14.0 %s -verify -fexperimental-new-constant-interpreter +// RUN: %clang_cc1 -xc++ -triple x86_64-apple-macosx10.14.0 %s -verify -DUSE_BUILTINS -fexperimental-new-constant-interpreter + typedef unsigned long size_t; #ifdef __cplusplus >From d80e62c13054c133ab12fe220a9febe3c62c284b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com> Date: Sat, 19 Jul 2025 23:09:05 +0200 Subject: [PATCH 2/2] Fast-path for single-byte chars --- clang/lib/AST/ByteCode/Context.cpp | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/clang/lib/AST/ByteCode/Context.cpp b/clang/lib/AST/ByteCode/Context.cpp index ebb809a33c1fc..9e683d71f83bc 100644 --- a/clang/lib/AST/ByteCode/Context.cpp +++ b/clang/lib/AST/ByteCode/Context.cpp @@ -245,6 +245,11 @@ bool Context::evaluateStrlen(State &Parent, const Expr *E, uint64_t &Result) { return false; unsigned N = Ptr.getNumElems(); + if (Ptr.elemSize() == 1) { + Result = strnlen(reinterpret_cast<const char *>(Ptr.getRawAddress()), N); + return Result != N; + } + PrimType ElemT = FieldDesc->getPrimType(); Result = 0; for (unsigned I = Ptr.getIndex(); I != N; ++I) { _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
