https://github.com/higher-performance updated
https://github.com/llvm/llvm-project/pull/107627
>From 581264c9ec198e98ff5f0f2c6e46073d79959a0b Mon Sep 17 00:00:00 2001
From: higher-performance <higher.performance.git...@gmail.com>
Date: Fri, 6 Sep 2024 14:16:15 -0400
Subject: [PATCH] Propagate lifetimebound from formal parameters to those in
the canonical declaration, then use the canonical declaration for analysis
Note that this doesn't handle the implicit 'this' parameter; that can be
addressed in a separate commit.
---
clang/lib/Sema/CheckExprLifetime.cpp | 15 +++++-----
clang/lib/Sema/SemaAttr.cpp | 34 +++++++++++++++--------
clang/test/SemaCXX/attr-lifetimebound.cpp | 5 ++++
3 files changed, 35 insertions(+), 19 deletions(-)
diff --git a/clang/lib/Sema/CheckExprLifetime.cpp
b/clang/lib/Sema/CheckExprLifetime.cpp
index a1a402b4a2b530..3d9858097f07dc 100644
--- a/clang/lib/Sema/CheckExprLifetime.cpp
+++ b/clang/lib/Sema/CheckExprLifetime.cpp
@@ -607,9 +607,9 @@ static void visitFunctionCallArguments(IndirectLocalPath
&Path, Expr *Call,
}
}
- for (unsigned I = 0,
- N = std::min<unsigned>(Callee->getNumParams(), Args.size());
- I != N; ++I) {
+ const FunctionDecl *CanonCallee = Callee->getCanonicalDecl();
+ unsigned NP = std::min(Callee->getNumParams(), CanonCallee->getNumParams());
+ for (unsigned I = 0, N = std::min<unsigned>(NP, Args.size()); I != N; ++I) {
Expr *Arg = Args[I];
RevertToOldSizeRAII RAII(Path);
if (auto *DAE = dyn_cast<CXXDefaultArgExpr>(Arg)) {
@@ -617,12 +617,13 @@ static void visitFunctionCallArguments(IndirectLocalPath
&Path, Expr *Call,
{IndirectLocalPathEntry::DefaultArg, DAE, DAE->getParam()});
Arg = DAE->getExpr();
}
- if (CheckCoroCall || Callee->getParamDecl(I)->hasAttr<LifetimeBoundAttr>())
- VisitLifetimeBoundArg(Callee->getParamDecl(I), Arg);
+ if (CheckCoroCall ||
+ CanonCallee->getParamDecl(I)->hasAttr<LifetimeBoundAttr>())
+ VisitLifetimeBoundArg(CanonCallee->getParamDecl(I), Arg);
else if (EnableGSLAnalysis && I == 0) {
// Perform GSL analysis for the first argument
- if (shouldTrackFirstArgument(Callee)) {
- VisitGSLPointerArg(Callee, Arg);
+ if (shouldTrackFirstArgument(CanonCallee)) {
+ VisitGSLPointerArg(CanonCallee, Arg);
} else if (auto *Ctor = dyn_cast<CXXConstructExpr>(Call);
Ctor && shouldTrackFirstArgumentForConstructor(Ctor)) {
VisitGSLPointerArg(Ctor->getConstructor(), Arg);
diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index 9fbad7ed67ccbe..85274aee785a58 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -216,7 +216,8 @@ void Sema::inferGslOwnerPointerAttribute(CXXRecordDecl
*Record) {
}
void Sema::inferLifetimeBoundAttribute(FunctionDecl *FD) {
- if (FD->getNumParams() == 0)
+ unsigned NumParams = FD->getNumParams();
+ if (NumParams == 0)
return;
if (unsigned BuiltinID = FD->getBuiltinID()) {
@@ -238,18 +239,13 @@ void Sema::inferLifetimeBoundAttribute(FunctionDecl *FD) {
default:
break;
}
- return;
- }
- if (auto *CMD = dyn_cast<CXXMethodDecl>(FD)) {
- const auto *CRD = CMD->getParent();
- if (!CRD->isInStdNamespace() || !CRD->getIdentifier())
- return;
-
- if (isa<CXXConstructorDecl>(CMD)) {
+ } else if (auto *CMD = dyn_cast<CXXMethodDecl>(FD)) {
+ const CXXRecordDecl *CRD = CMD->getParent();
+ if (CRD->isInStdNamespace() && CRD->getIdentifier() &&
+ isa<CXXConstructorDecl>(CMD)) {
auto *Param = CMD->getParamDecl(0);
- if (Param->hasAttr<LifetimeBoundAttr>())
- return;
- if (CRD->getName() == "basic_string_view" &&
+ if (!Param->hasAttr<LifetimeBoundAttr>() &&
+ CRD->getName() == "basic_string_view" &&
Param->getType()->isPointerType()) {
// construct from a char array pointed by a pointer.
// basic_string_view(const CharT* s);
@@ -265,6 +261,20 @@ void Sema::inferLifetimeBoundAttribute(FunctionDecl *FD) {
LifetimeBoundAttr::CreateImplicit(Context, FD->getLocation()));
}
}
+ } else if (auto *CanonDecl = FD->getCanonicalDecl(); FD != CanonDecl) {
+ // Propagate the lifetimebound attribute from parameters to the canonical
+ // declaration.
+ // Note that this doesn't include the implicit 'this' parameter, as the
+ // attribute is applied to the function type in that case.
+ unsigned NP = std::min(NumParams, CanonDecl->getNumParams());
+ for (unsigned I = 0; I < NP; ++I) {
+ auto *CanonParam = CanonDecl->getParamDecl(I);
+ if (!CanonParam->hasAttr<LifetimeBoundAttr>() &&
+ FD->getParamDecl(I)->hasAttr<LifetimeBoundAttr>()) {
+ CanonParam->addAttr(LifetimeBoundAttr::CreateImplicit(
+ Context, CanonParam->getLocation()));
+ }
+ }
}
}
diff --git a/clang/test/SemaCXX/attr-lifetimebound.cpp
b/clang/test/SemaCXX/attr-lifetimebound.cpp
index 81e9193cf76a04..fb5a68f2497013 100644
--- a/clang/test/SemaCXX/attr-lifetimebound.cpp
+++ b/clang/test/SemaCXX/attr-lifetimebound.cpp
@@ -19,6 +19,10 @@ namespace usage_invalid {
namespace usage_ok {
struct IntRef { int *target; };
+ const int &crefparam(const int ¶m); // Omitted in first decl
+ const int &crefparam(const int ¶m); // Omitted in second decl
+ const int &crefparam(const int ¶m [[clang::lifetimebound]]); // Add LB
+ const int &crefparam(const int ¶m) { return param; } // Omit in impl
int &refparam(int ¶m [[clang::lifetimebound]]);
int &classparam(IntRef param [[clang::lifetimebound]]);
@@ -48,6 +52,7 @@ namespace usage_ok {
int *p = A().class_member(); // expected-warning {{temporary whose address
is used as value of local variable 'p' will be destroyed at the end of the
full-expression}}
int *q = A(); // expected-warning {{temporary whose address is used as value
of local variable 'q' will be destroyed at the end of the full-expression}}
int *r = A(1); // expected-warning {{temporary whose address is used as
value of local variable 'r' will be destroyed at the end of the
full-expression}}
+ const int& s = crefparam(2); // expected-warning {{temporary bound to local
reference 's' will be destroyed at the end of the full-expression}}
void test_assignment() {
p = A().class_member(); // expected-warning {{object backing the pointer p
will be destroyed at the end of the full-expression}}
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