Reapply "[clang] Introduce [[clang::lifetime_capture_by(X)]] #115823
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@llvm/pr-subscribers-clang Author: Utkarsh Saxena (usx95) ChangesFix compile time regression and memory leak Full diff: https://github.com/llvm/llvm-project/pull/115823.diff 11 Files Affected:
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 4ef48bed58d95c..482b30848b57e8 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -449,6 +449,9 @@ Attribute Changes in Clang
- Fix a bug where clang doesn't automatically apply the ``[[gsl::Owner]]`` or
``[[gsl::Pointer]]`` to STL explicit template specialization decls. (#GH109442)
+- Clang now supports ``[[clang::lifetime_capture_by(X)]]``. Similar to lifetimebound, this can be
+ used to specify when a reference to a function parameter is captured by another capturing entity ``X``.
+
Improvements to Clang's diagnostics
-----------------------------------
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index a631e81d40aa68..04e86bbe6a9c3c 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -1889,6 +1889,39 @@ def LifetimeBound : DeclOrTypeAttr {
let SimpleHandler = 1;
}
+def LifetimeCaptureBy : DeclOrTypeAttr {
+ let Spellings = [Clang<"lifetime_capture_by", 0>];
+ let Subjects = SubjectList<[ParmVar, ImplicitObjectParameter], ErrorDiag>;
+ let Args = [VariadicParamOrParamIdxArgument<"Params">];
+ let Documentation = [LifetimeCaptureByDocs];
+ let AdditionalMembers = [{
+private:
+ SmallVector<IdentifierInfo*> ArgIdents;
+ SmallVector<SourceLocation> ArgLocs;
+
+public:
+ static constexpr int THIS = 0;
+ static constexpr int INVALID = -1;
+ static constexpr int UNKNOWN = -2;
+ static constexpr int GLOBAL = -3;
+
+ void setArgs(SmallVector<IdentifierInfo*> Idents,
+ SmallVector<SourceLocation> Locs) {
+ assert(Idents.size() == Locs.size());
+ assert(Idents.size() == params_Size);
+ ArgIdents = std::move(Idents);
+ ArgLocs = std::move(Locs);
+ }
+
+ ArrayRef<IdentifierInfo*> getArgIdents() const { return ArgIdents; }
+ ArrayRef<SourceLocation> getArgLocs() const { return ArgLocs; }
+ void setParamIdx(size_t Idx, int Val) {
+ assert(Idx < params_Size);
+ params_[Idx] = Val;
+ }
+}];
+}
+
def TrivialABI : InheritableAttr {
// This attribute does not have a C [[]] spelling because it requires the
// CPlusPlus language option.
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index b64dbef6332e6a..21fcd183e8969c 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3918,6 +3918,75 @@ have their lifetimes extended.
}];
}
+def LifetimeCaptureByDocs : Documentation {
+ let Category = DocCatFunction;
+ let Content = [{
+ Similar to `lifetimebound`_, the ``lifetime_capture_by(X)`` attribute on a function
+parameter or implicit object parameter indicates that that objects that are referred to
+by that parameter may also be referred to by the capturing entity ``X``.
+
+By default, a reference is considered to refer to its referenced object, a
+pointer is considered to refer to its pointee, a ``std::initializer_list<T>``
+is considered to refer to its underlying array, and aggregates (arrays and
+simple ``struct``\s) are considered to refer to all objects that their
+transitive subobjects refer to.
+
+The capturing entity ``X`` can be one of the following:
+- Another (named) function parameter.
+
+ .. code-block:: c++
+
+ void addToSet(std::string_view a [[clang::lifetime_capture_by(s)]], std::set<std::string_view>& s) {
+ s.insert(a);
+ }
+
+- ``this`` (in case of member functions).
+
+ .. code-block:: c++
+
+ class S {
+ void addToSet(std::string_view a [[clang::lifetime_capture_by(this)]]) {
+ s.insert(a);
+ }
+ std::set<std::string_view> s;
+ };
+
+- 'global', 'unknown' (without quotes).
+
+ .. code-block:: c++
+
+ std::set<std::string_view> s;
+ void addToSet(std::string_view a [[clang::lifetime_capture_by(global)]]) {
+ s.insert(a);
+ }
+ void addSomewhere(std::string_view a [[clang::lifetime_capture_by(unknown)]]);
+
+The attribute can be applied to the implicit ``this`` parameter of a member
+function by writing the attribute after the function type:
+
+.. code-block:: c++
+
+ struct S {
+ const char *data(std::set<S*>& s) [[clang::lifetime_capture_by(s)]] {
+ s.insert(this);
+ }
+ };
+
+The attribute supports specifying more than one capturing entities:
+
+.. code-block:: c++
+
+ void addToSets(std::string_view a [[clang::lifetime_capture_by(s1, s2)]],
+ std::set<std::string_view>& s1,
+ std::set<std::string_view>& s2) {
+ s1.insert(a);
+ s2.insert(a);
+ }
+
+.. _`lifetimebound`: https://clang.llvm.org/docs/AttributeReference.html#lifetimebound
+ }];
+}
+
def TrivialABIDocs : Documentation {
let Category = DocCatDecl;
let Content = [{
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index a5d97d7e545ffd..f4452fbb57e736 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3383,6 +3383,20 @@ def err_callback_callee_is_variadic : Error<
"'callback' attribute callee may not be variadic">;
def err_callback_implicit_this_not_available : Error<
"'callback' argument at position %0 references unavailable implicit 'this'">;
+
+def err_capture_by_attribute_multiple : Error<
+ "multiple 'lifetime_capture' attributes specified">;
+def err_capture_by_attribute_no_entity : Error<
+ "'lifetime_capture_by' attribute specifies no capturing entity">;
+def err_capture_by_implicit_this_not_available : Error<
+ "'lifetime_capture_by' argument references unavailable implicit 'this'">;
+def err_capture_by_attribute_argument_unknown : Error<
+ "'lifetime_capture_by' attribute argument %0 is not a known function parameter"
+ "; must be a function parameter, 'this', 'global' or 'unknown'">;
+def err_capture_by_references_itself : Error<"'lifetime_capture_by' argument references itself">;
+def err_capture_by_param_uses_reserved_name : Error<
+ "parameter cannot be named '%select{global|unknown}0' while using 'lifetime_capture_by(%select{global|unknown}0)'">;
+
def err_init_method_bad_return_type : Error<
"init methods must return an object pointer type, not %0">;
def err_attribute_invalid_size : Error<
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index fad446a05e782f..d6f3508a5243f3 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -1760,6 +1760,14 @@ class Sema final : public SemaBase {
/// Add [[gsl::Pointer]] attributes for std:: types.
void inferGslPointerAttribute(TypedefNameDecl *TD);
+ LifetimeCaptureByAttr *ParseLifetimeCaptureByAttr(const ParsedAttr &AL,
+ StringRef ParamName);
+ // Processes the argument 'X' in [[clang::lifetime_capture_by(X)]]. Since 'X'
+ // can be the name of a function parameter, we need to parse the function
+ // declaration and rest of the parameters before processesing 'X'. Therefore
+ // do this lazily instead of processing while parsing the annotation itself.
+ void LazyProcessLifetimeCaptureByParams(FunctionDecl *FD);
+
/// Add _Nullable attributes for std:: types.
void inferNullableClassAttribute(CXXRecordDecl *CRD);
diff --git a/clang/lib/AST/TypePrinter.cpp b/clang/lib/AST/TypePrinter.cpp
index 6d8db5cf4ffd22..a073a6a4b7d454 100644
--- a/clang/lib/AST/TypePrinter.cpp
+++ b/clang/lib/AST/TypePrinter.cpp
@@ -25,6 +25,7 @@
#include "clang/AST/TextNodeDumper.h"
#include "clang/AST/Type.h"
#include "clang/Basic/AddressSpaces.h"
+#include "clang/Basic/AttrKinds.h"
#include "clang/Basic/ExceptionSpecificationType.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/LLVM.h"
@@ -1909,6 +1910,19 @@ void TypePrinter::printAttributedAfter(const AttributedType *T,
OS << " [[clang::lifetimebound]]";
return;
}
+ if (T->getAttrKind() == attr::LifetimeCaptureBy) {
+ OS << " [[clang::lifetime_capture_by(";
+ if (auto *attr = dyn_cast_or_null<LifetimeCaptureByAttr>(T->getAttr())) {
+ auto Idents = attr->getArgIdents();
+ for (unsigned I = 0; I < Idents.size(); ++I) {
+ OS << Idents[I]->getName();
+ if (I != Idents.size() - 1)
+ OS << ", ";
+ }
+ }
+ OS << ")]]";
+ return;
+ }
// The printing of the address_space attribute is handled by the qualifier
// since it is still stored in the qualifier. Return early to prevent printing
@@ -1976,6 +1990,7 @@ void TypePrinter::printAttributedAfter(const AttributedType *T,
case attr::SizedBy:
case attr::SizedByOrNull:
case attr::LifetimeBound:
+ case attr::LifetimeCaptureBy:
case attr::TypeNonNull:
case attr::TypeNullable:
case attr::TypeNullableResult:
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 61c29e320d5c73..a3bc8e4191c819 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -16687,6 +16687,7 @@ void Sema::AddKnownFunctionAttributes(FunctionDecl *FD) {
}
}
+ LazyProcessLifetimeCaptureByParams(FD);
inferLifetimeBoundAttribute(FD);
AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(FD);
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index d05d326178e1b8..d00f10ddfae844 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -14,6 +14,7 @@
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/AST/CXXInheritance.h"
+#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
@@ -3867,6 +3868,116 @@ static void handleCallbackAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
S.Context, AL, EncodingIndices.data(), EncodingIndices.size()));
}
+LifetimeCaptureByAttr *Sema::ParseLifetimeCaptureByAttr(const ParsedAttr &AL,
+ StringRef ParamName) {
+ // Atleast one capture by is required.
+ if (AL.getNumArgs() == 0) {
+ Diag(AL.getLoc(), diag::err_capture_by_attribute_no_entity)
+ << AL.getRange();
+ return nullptr;
+ }
+ SmallVector<IdentifierInfo *> ParamIdents;
+ SmallVector<SourceLocation> ParamLocs;
+ for (unsigned I = 0; I < AL.getNumArgs(); ++I) {
+ if (AL.isArgExpr(I)) {
+ Expr *E = AL.getArgAsExpr(I);
+ Diag(E->getExprLoc(), diag::err_capture_by_attribute_argument_unknown)
+ << E << E->getExprLoc();
+ continue;
+ }
+ assert(AL.isArgIdent(I));
+ IdentifierLoc *IdLoc = AL.getArgAsIdent(I);
+ if (IdLoc->Ident->getName() == ParamName) {
+ Diag(IdLoc->Loc, diag::err_capture_by_references_itself) << IdLoc->Loc;
+ continue;
+ }
+ ParamIdents.push_back(IdLoc->Ident);
+ ParamLocs.push_back(IdLoc->Loc);
+ }
+ SmallVector<int> FakeParamIndices(ParamIdents.size(),
+ LifetimeCaptureByAttr::INVALID);
+ LifetimeCaptureByAttr *CapturedBy = ::new (Context) LifetimeCaptureByAttr(
+ Context, AL, FakeParamIndices.data(), FakeParamIndices.size());
+ CapturedBy->setArgs(std::move(ParamIdents), std::move(ParamLocs));
+ return CapturedBy;
+}
+
+static void handleLifetimeCaptureByAttr(Sema &S, Decl *D,
+ const ParsedAttr &AL) {
+ // Do not allow multiple attributes.
+ if (D->hasAttr<LifetimeCaptureByAttr>()) {
+ S.Diag(AL.getLoc(), diag::err_capture_by_attribute_multiple)
+ << AL.getRange();
+ return;
+ }
+ auto *PVD = dyn_cast<ParmVarDecl>(D);
+ assert(PVD);
+ auto *CaptureByAttr = S.ParseLifetimeCaptureByAttr(AL, PVD->getName());
+ if (CaptureByAttr)
+ D->addAttr(CaptureByAttr);
+}
+
+void Sema::LazyProcessLifetimeCaptureByParams(FunctionDecl *FD) {
+ bool HasImplicitThisParam = isInstanceMethod(FD);
+ SmallVector<LifetimeCaptureByAttr *, 1> Attrs;
+ for (ParmVarDecl *PVD : FD->parameters())
+ if (auto *A = PVD->getAttr<LifetimeCaptureByAttr>())
+ Attrs.push_back(A);
+ if (HasImplicitThisParam) {
+ TypeSourceInfo *TSI = FD->getTypeSourceInfo();
+ if (!TSI)
+ return;
+ AttributedTypeLoc ATL;
+ for (TypeLoc TL = TSI->getTypeLoc();
+ (ATL = TL.getAsAdjusted<AttributedTypeLoc>());
+ TL = ATL.getModifiedLoc()) {
+ if (auto *A = ATL.getAttrAs<LifetimeCaptureByAttr>())
+ Attrs.push_back(const_cast<LifetimeCaptureByAttr *>(A));
+ }
+ }
+ if (Attrs.empty())
+ return;
+ llvm::StringMap<int> NameIdxMapping;
+ NameIdxMapping["global"] = LifetimeCaptureByAttr::GLOBAL;
+ NameIdxMapping["unknown"] = LifetimeCaptureByAttr::UNKNOWN;
+ int Idx = 0;
+ if (HasImplicitThisParam) {
+ NameIdxMapping["this"] = 0;
+ Idx++;
+ }
+ for (const ParmVarDecl *PVD : FD->parameters())
+ NameIdxMapping[PVD->getName()] = Idx++;
+ auto DisallowReservedParams = [&](StringRef Reserved) {
+ for (const ParmVarDecl *PVD : FD->parameters())
+ if (PVD->getName() == Reserved)
+ Diag(PVD->getLocation(), diag::err_capture_by_param_uses_reserved_name)
+ << (PVD->getName() == "unknown");
+ };
+ auto HandleCaptureBy = [&](LifetimeCaptureByAttr *CapturedBy) {
+ if (!CapturedBy)
+ return;
+ const auto &Entities = CapturedBy->getArgIdents();
+ for (size_t I = 0; I < Entities.size(); ++I) {
+ StringRef Name = Entities[I]->getName();
+ auto It = NameIdxMapping.find(Name);
+ if (It == NameIdxMapping.end()) {
+ auto Loc = CapturedBy->getArgLocs()[I];
+ if (!HasImplicitThisParam && Name == "this")
+ Diag(Loc, diag::err_capture_by_implicit_this_not_available) << Loc;
+ else
+ Diag(Loc, diag::err_capture_by_attribute_argument_unknown)
+ << Entities[I] << Loc;
+ continue;
+ }
+ if (Name == "unknown" || Name == "global")
+ DisallowReservedParams(Name);
+ CapturedBy->setParamIdx(I, It->second);
+ }
+ };
+ for (auto *A : Attrs)
+ HandleCaptureBy(A);
+}
+
static bool isFunctionLike(const Type &T) {
// Check for explicit function types.
// 'called_once' is only supported in Objective-C and it has
@@ -6644,6 +6755,9 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
case ParsedAttr::AT_Callback:
handleCallbackAttr(S, D, AL);
break;
+ case ParsedAttr::AT_LifetimeCaptureBy:
+ handleLifetimeCaptureByAttr(S, D, AL);
+ break;
case ParsedAttr::AT_CalledOnce:
handleCalledOnceAttr(S, D, AL);
break;
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 515b9f689a248a..eb7516b3ef1ece 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -8609,6 +8609,15 @@ static void HandleLifetimeBoundAttr(TypeProcessingState &State,
}
}
+static void HandleLifetimeCaptureByAttr(TypeProcessingState &State,
+ QualType &CurType, ParsedAttr &PA) {
+ if (State.getDeclarator().isDeclarationOfFunction()) {
+ auto *Attr = State.getSema().ParseLifetimeCaptureByAttr(PA, "this");
+ if (Attr)
+ CurType = State.getAttributedType(Attr, CurType, CurType);
+ }
+}
+
static void HandleHLSLParamModifierAttr(TypeProcessingState &State,
QualType &CurType,
const ParsedAttr &Attr, Sema &S) {
@@ -8770,6 +8779,10 @@ static void processTypeAttrs(TypeProcessingState &state, QualType &type,
if (TAL == TAL_DeclChunk)
HandleLifetimeBoundAttr(state, type, attr);
break;
+ case ParsedAttr::AT_LifetimeCaptureBy:
+ if (TAL == TAL_DeclChunk)
+ HandleLifetimeCaptureByAttr(state, type, attr);
+ break;
case ParsedAttr::AT_NoDeref: {
// FIXME: `noderef` currently doesn't work correctly in [[]] syntax.
diff --git a/clang/test/AST/attr-lifetime-capture-by.cpp b/clang/test/AST/attr-lifetime-capture-by.cpp
new file mode 100644
index 00000000000000..da2eb0cf3d592e
--- /dev/null
+++ b/clang/test/AST/attr-lifetime-capture-by.cpp
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 %s -ast-dump | FileCheck %s
+
+// Verify that we print the [[clang::lifetime_capture_by(X)]] attribute.
+
+struct S {
+ void foo(int &a, int &b) [[clang::lifetime_capture_by(a, b, global)]];
+};
+
+// CHECK: CXXMethodDecl {{.*}}clang::lifetime_capture_by(a, b, global)
diff --git a/clang/test/SemaCXX/attr-lifetime-capture-by.cpp b/clang/test/SemaCXX/attr-lifetime-capture-by.cpp
new file mode 100644
index 00000000000000..3115dc8d6150c9
--- /dev/null
+++ b/clang/test/SemaCXX/attr-lifetime-capture-by.cpp
@@ -0,0 +1,46 @@
+// RUN: %clang_cc1 -std=c++23 -verify %s
+
+struct S {
+ const int *x;
+ void captureInt(const int&x [[clang::lifetime_capture_by(this)]]) { this->x = &x; }
+};
+
+///////////////////////////
+// Test for valid usages.
+///////////////////////////
+[[clang::lifetime_capture_by(unknown)]] // expected-error {{'lifetime_capture_by' attribute only applies to parameters and implicit object parameters}}
+void nonMember(
+ const int &x1 [[clang::lifetime_capture_by(s, t)]],
+ S &s,
+ S &t,
+ const int &x2 [[clang::lifetime_capture_by(12345 + 12)]], // expected-error {{'lifetime_capture_by' attribute argument 12345 + 12 is not a known function parameter; must be a function parameter, 'this', 'global' or 'unknown'}}
+ const int &x3 [[clang::lifetime_capture_by(abcdefgh)]], // expected-error {{'lifetime_capture_by' attribute argument 'abcdefgh' is not a known function parameter; must be a function parameter, 'this', 'global' or 'unknown'}}
+ const int &x4 [[clang::lifetime_capture_by("abcdefgh")]], // expected-error {{'lifetime_capture_by' attribute argument "abcdefgh" is not a known function parameter; must be a function parameter, 'this', 'global' or 'unknown'}}
+ const int &x5 [[clang::lifetime_capture_by(this)]], // expected-error {{'lifetime_capture_by' argument references unavailable implicit 'this'}}
+ const int &x6 [[clang::lifetime_capture_by()]], // expected-error {{'lifetime_capture_by' attribute specifies no capturing entity}}
+ const int& x7 [[clang::lifetime_capture_by(u,
+ x7)]], // expected-error {{'lifetime_capture_by' argument references itself}}
+ const int &x8 [[clang::lifetime_capture_by(global)]],
+ const int &x9 [[clang::lifetime_capture_by(unknown)]],
+ const S& u
+ )
+{
+ s.captureInt(x1);
+}
+
+void unknown_param_name(const int& unknown, // expected-error {{parameter cannot be named 'unknown' while using 'lifetime_capture_by(unknown)'}}
+ const int& s [[clang::lifetime_capture_by(unknown)]]);
+void global_param_name(const int& global, // expected-error {{parameter cannot be named 'global' while using 'lifetime_capture_by(global)'}}
+ const int& s [[clang::lifetime_capture_by(global)]]);
+struct T {
+ void member(
+ const int &x [[clang::lifetime_capture_by(s)]],
+ S &s,
+ S &t,
+ const int &y [[clang::lifetime_capture_by(s)]],
+ const int &z [[clang::lifetime_capture_by(this, x, y)]],
+ const int &u [[clang::lifetime_capture_by(global, unknown, x, s)]])
+ {
+ s.captureInt(x);
+ }
+};
|
usx95
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Nov 12, 2024
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Can you clarify the memory leak issue? It’s not immediately obvious to me. It would be helpful to explain these two issues and describe how the reland addresses them in the PR description. |
hokein
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Nov 12, 2024
|
Looks like I have not fully resolved the memory leak and only avoided it by having larger portion of vector on stack. The leak happens for the allocation: Suprisingly commenting out the |
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Fixed the issues. Added more details in the description. |
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Xazax-hun
approved these changes
Nov 12, 2024
clang/include/clang/Basic/Attr.td
Outdated
| let Documentation = [LifetimeCaptureByDocs]; | ||
| let AdditionalMembers = [{ | ||
| private: | ||
| IdentifierInfo** ArgIdents; |
There was a problem hiding this comment.
Not for this PR, but I think one option would be to have a trailing array of pairs, so we don't need multiple allocations but we can embed the arguments in the attribute. Not sure if it is cumbersome to do for attributes, so it is just a random idea for the future.
hokein
reviewed
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Nov 13, 2024
…5823) Fix compile time regression and memory leak In the previous change, we saw: - Memory leak: https://lab.llvm.org/buildbot/#/builders/169/builds/5193 - 0.5% Compile time regression [link](https://llvm-compile-time-tracker.com/compare.php?from=4a68e4cbd2423dcacada8162ab7c4bb8d7f7e2cf&to=8c4331c1abeb33eabf3cdbefa7f2b6e0540e7f4f&stat=instructions:u) For compile time regression, we make the Param->Idx `StringMap` for **all** functions. This `StringMap` is expensive and should not be computed when none of the params are annotated with `[[clang::lifetime_capture_by(X)]]`. For the memory leak, the small vectors used in Attribute are not destroyed because the attributes are allocated through ASTContext's allocator. We therefore need a raw array in this case. Cherry-picked from 3e20bae
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Fix compile time regression and memory leak
See https://github.com/llvm/llvm-project/pull/115823/files/3c233df64906972016c26909263cfd53940d87a0..3392c6edf9e561c1469cc1205a32aeccec98e804 for new changes.
In the previous change, we saw:
For compile time regression, we make the Param->Idx
StringMapfor all functions. ThisStringMapis expensive and should not be computed when none of the params are annotated with[[clang::lifetime_capture_by(X)]].For the memory leak, the small vectors used in Attribute are not destroyed because the attributes are allocated through ASTContext's allocator. We therefore need a raw array in this case.