[clang] [Clang] Add __builtin_get_counted_by builtin (PR #102549)
Bill Wendling via cfe-commits
cfe-commits at lists.llvm.org
Wed Aug 14 14:04:12 PDT 2024
https://github.com/bwendling updated https://github.com/llvm/llvm-project/pull/102549
>From 7ba43ae2b737fbd868848a23b58b3965f8d36ce1 Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Tue, 6 Aug 2024 17:49:01 -0700
Subject: [PATCH 01/11] [WIP][Clang] Add __builtin_get_counted_by builtin
The __builtin_get_counted_by builtin is used on a flexible array
pointer and returns a pointer to the "counted_by" attribute's COUNT
argument, which is a field in the same non-anonymous struct as the
flexible array member. This is useful for automatically setting the
count field without needing the programmer's intervention. Otherwise
it's possible to get this anti-pattern:
ptr = alloc(<ty>, COUNT);
ptr->FAM[9] = 37; /* <<< Sanitizer will complain */
ptr->count = COUNT;
---
clang/include/clang/Basic/Builtins.td | 6 ++++
clang/lib/CodeGen/CGBuiltin.cpp | 22 ++++++++++++
clang/lib/CodeGen/CGExpr.cpp | 29 +++++++++-------
clang/lib/CodeGen/CodeGenFunction.h | 4 +++
clang/lib/Sema/SemaExpr.cpp | 49 +++++++++++++++++++++++++--
5 files changed, 96 insertions(+), 14 deletions(-)
diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td
index b025a7681bfac3..254cd157d5f9d0 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/clang/include/clang/Basic/Builtins.td
@@ -4774,3 +4774,9 @@ def ArithmeticFence : LangBuiltin<"ALL_LANGUAGES"> {
let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
+
+def GetCountedBy : Builtin {
+ let Spellings = ["__builtin_get_counted_by"];
+ let Attributes = [NoThrow];
+ let Prototype = "size_t*(void*)";
+}
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 51d1162c6e403c..859249be72c07e 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3563,6 +3563,28 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
return RValue::get(emitBuiltinObjectSize(E->getArg(0), Type, ResType,
/*EmittedE=*/nullptr, IsDynamic));
}
+ case Builtin::BI__builtin_get_counted_by: {
+ llvm::Value *Result = nullptr;
+
+ if (const MemberExpr *ME =
+ dyn_cast<MemberExpr>(E->getArg(0)->IgnoreImpCasts())) {
+ bool IsFlexibleArrayMember = ME->isFlexibleArrayMemberLike(
+ getContext(), getLangOpts().getStrictFlexArraysLevel(),
+ /*IgnoreTemplateOrMacroSubstitution=*/false);
+
+ // TODO: Probably have to handle horrible casting crap here.
+
+ // FIXME: Emit a diagnostic?
+ if (!ME->HasSideEffects(getContext()) && IsFlexibleArrayMember &&
+ ME->getMemberDecl()->getType()->isCountAttributedType()) {
+ const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl());
+ if (const FieldDecl *CountFD = FindCountedByField(FAMDecl))
+ Result = GetCountedByFieldExprGEP(ME, FAMDecl, CountFD);
+ }
+ }
+
+ return RValue::get(Result);
+ }
case Builtin::BI__builtin_prefetch: {
Value *Locality, *RW, *Address = EmitScalarExpr(E->getArg(0));
// FIXME: Technically these constants should of type 'int', yes?
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index a1dce741c78a11..55cd95c08e3ffc 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1100,15 +1100,7 @@ static bool getGEPIndicesToField(CodeGenFunction &CGF, const RecordDecl *RD,
return false;
}
-/// This method is typically called in contexts where we can't generate
-/// side-effects, like in __builtin_dynamic_object_size. When finding
-/// expressions, only choose those that have either already been emitted or can
-/// be loaded without side-effects.
-///
-/// - \p FAMDecl: the \p Decl for the flexible array member. It may not be
-/// within the top-level struct.
-/// - \p CountDecl: must be within the same non-anonymous struct as \p FAMDecl.
-llvm::Value *CodeGenFunction::EmitLoadOfCountedByField(
+llvm::Value *CodeGenFunction::GetCountedByFieldExprGEP(
const Expr *Base, const FieldDecl *FAMDecl, const FieldDecl *CountDecl) {
const RecordDecl *RD = CountDecl->getParent()->getOuterLexicalRecordContext();
@@ -1141,12 +1133,25 @@ llvm::Value *CodeGenFunction::EmitLoadOfCountedByField(
return nullptr;
Indices.push_back(Builder.getInt32(0));
- Res = Builder.CreateInBoundsGEP(
+ return Builder.CreateInBoundsGEP(
ConvertType(QualType(RD->getTypeForDecl(), 0)), Res,
RecIndicesTy(llvm::reverse(Indices)), "..counted_by.gep");
+}
- return Builder.CreateAlignedLoad(ConvertType(CountDecl->getType()), Res,
- getIntAlign(), "..counted_by.load");
+/// This method is typically called in contexts where we can't generate
+/// side-effects, like in __builtin_dynamic_object_size. When finding
+/// expressions, only choose those that have either already been emitted or can
+/// be loaded without side-effects.
+///
+/// - \p FAMDecl: the \p Decl for the flexible array member. It may not be
+/// within the top-level struct.
+/// - \p CountDecl: must be within the same non-anonymous struct as \p FAMDecl.
+llvm::Value *CodeGenFunction::EmitLoadOfCountedByField(
+ const Expr *Base, const FieldDecl *FAMDecl, const FieldDecl *CountDecl) {
+ if (llvm::Value *GEP = GetCountedByFieldExprGEP(Base, FAMDecl, CountDecl))
+ return Builder.CreateAlignedLoad(ConvertType(CountDecl->getType()), GEP,
+ getIntAlign(), "..counted_by.load");
+ return nullptr;
}
const FieldDecl *CodeGenFunction::FindCountedByField(const FieldDecl *FD) {
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 1c0a0e117e5607..e5f5b94bba54b0 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -3309,6 +3309,10 @@ class CodeGenFunction : public CodeGenTypeCache {
/// \p nullptr if either the attribute or the field doesn't exist.
const FieldDecl *FindCountedByField(const FieldDecl *FD);
+ llvm::Value *GetCountedByFieldExprGEP(const Expr *Base,
+ const FieldDecl *FAMDecl,
+ const FieldDecl *CountDecl);
+
/// Build an expression accessing the "counted_by" field.
llvm::Value *EmitLoadOfCountedByField(const Expr *Base,
const FieldDecl *FAMDecl,
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 21c8ae6bad0eae..048d0c4ae49726 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6390,9 +6390,26 @@ ExprResult Sema::ActOnCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
currentEvaluationContext().ReferenceToConsteval.erase(DRE);
}
}
+
return Call;
}
+const FieldDecl *FindCountedByField(const FieldDecl *FD) {
+ if (!FD)
+ return nullptr;
+
+ const auto *CAT = FD->getType()->getAs<CountAttributedType>();
+ if (!CAT)
+ return nullptr;
+
+ const auto *CountDRE = cast<DeclRefExpr>(CAT->getCountExpr());
+ const auto *CountDecl = CountDRE->getDecl();
+ if (const auto *IFD = dyn_cast<IndirectFieldDecl>(CountDecl))
+ CountDecl = IFD->getAnonField();
+
+ return dyn_cast<FieldDecl>(CountDecl);
+}
+
ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
MultiExprArg ArgExprs, SourceLocation RParenLoc,
Expr *ExecConfig, bool IsExecConfig,
@@ -6590,8 +6607,36 @@ ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
return CallExpr::Create(Context, Fn, ArgExprs, Context.DependentTy,
VK_PRValue, RParenLoc, CurFPFeatureOverrides());
}
- return BuildResolvedCallExpr(Fn, NDecl, LParenLoc, ArgExprs, RParenLoc,
- ExecConfig, IsExecConfig);
+
+ Result = BuildResolvedCallExpr(Fn, NDecl, LParenLoc, ArgExprs, RParenLoc,
+ ExecConfig, IsExecConfig);
+
+ if (FunctionDecl *FDecl = dyn_cast_or_null<FunctionDecl>(NDecl);
+ FDecl && FDecl->getBuiltinID() == Builtin::BI__builtin_get_counted_by) {
+ if (const MemberExpr *ME =
+ dyn_cast<MemberExpr>(ArgExprs[0]->IgnoreImpCasts())) {
+ bool IsFlexibleArrayMember = ME->isFlexibleArrayMemberLike(
+ Context, getLangOpts().getStrictFlexArraysLevel(),
+ /*IgnoreTemplateOrMacroSubstitution=*/false);
+
+ // TODO: Probably have to handle horrible casting crap here.
+
+ // FIXME: Emit a diagnostic?
+ if (!ME->HasSideEffects(Context) && IsFlexibleArrayMember &&
+ ME->getMemberDecl()->getType()->isCountAttributedType()) {
+ const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl());
+ if (const FieldDecl *CountFD = FindCountedByField(FAMDecl)) {
+ QualType PtrTy = Context.getPointerType(CountFD->getType());
+ Result = CStyleCastExpr::Create(
+ Context, PtrTy, VK_LValue, CK_BitCast, Result.get(), nullptr,
+ FPOptionsOverride(), Context.CreateTypeSourceInfo(PtrTy),
+ LParenLoc, RParenLoc);
+ }
+ }
+ }
+ }
+
+ return Result;
}
Expr *Sema::BuildBuiltinCallExpr(SourceLocation Loc, Builtin::ID Id,
>From 3c42b388f42c2570e6ce7b168601f6f69a959ea5 Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Wed, 7 Aug 2024 10:32:28 -0700
Subject: [PATCH 02/11] If the 'counted_by' attribute doesn't exist, then
return nullptr.
---
clang/lib/CodeGen/CGBuiltin.cpp | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 859249be72c07e..bf8fe007f979f3 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3580,6 +3580,10 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl());
if (const FieldDecl *CountFD = FindCountedByField(FAMDecl))
Result = GetCountedByFieldExprGEP(ME, FAMDecl, CountFD);
+ } else {
+ E->getType()->dump();
+ ConvertType(E->getType())->dump();
+ Result = llvm::ConstantPointerNull::get(cast<llvm::PointerType>(ConvertType(E->getType())));
}
}
>From 23efe69d0b279b9e14467d75ea48e1d0b1831a23 Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Wed, 7 Aug 2024 10:36:01 -0700
Subject: [PATCH 03/11] Remove debugging code.
---
clang/lib/CodeGen/CGBuiltin.cpp | 2 --
1 file changed, 2 deletions(-)
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index bf8fe007f979f3..07d46b2f74de38 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3581,8 +3581,6 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
if (const FieldDecl *CountFD = FindCountedByField(FAMDecl))
Result = GetCountedByFieldExprGEP(ME, FAMDecl, CountFD);
} else {
- E->getType()->dump();
- ConvertType(E->getType())->dump();
Result = llvm::ConstantPointerNull::get(cast<llvm::PointerType>(ConvertType(E->getType())));
}
}
>From 1c693069bda9576c7159c188003f321a6d5ed216 Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Wed, 7 Aug 2024 10:38:42 -0700
Subject: [PATCH 04/11] Make returning a nullptr the default.
---
clang/lib/CodeGen/CGBuiltin.cpp | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 07d46b2f74de38..b92fe7a6469f42 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3564,7 +3564,8 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
/*EmittedE=*/nullptr, IsDynamic));
}
case Builtin::BI__builtin_get_counted_by: {
- llvm::Value *Result = nullptr;
+ llvm::Value *Result =
+ llvm::ConstantPointerNull::get(cast<llvm::PointerType>(ConvertType(E->getType())));
if (const MemberExpr *ME =
dyn_cast<MemberExpr>(E->getArg(0)->IgnoreImpCasts())) {
@@ -3580,8 +3581,6 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl());
if (const FieldDecl *CountFD = FindCountedByField(FAMDecl))
Result = GetCountedByFieldExprGEP(ME, FAMDecl, CountFD);
- } else {
- Result = llvm::ConstantPointerNull::get(cast<llvm::PointerType>(ConvertType(E->getType())));
}
}
>From c8c40044fbded04020b3b2759b8ff007ae54d043 Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Wed, 7 Aug 2024 10:39:05 -0700
Subject: [PATCH 05/11] clang-format
---
clang/lib/CodeGen/CGBuiltin.cpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index b92fe7a6469f42..a703d1173b9be2 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3564,8 +3564,8 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
/*EmittedE=*/nullptr, IsDynamic));
}
case Builtin::BI__builtin_get_counted_by: {
- llvm::Value *Result =
- llvm::ConstantPointerNull::get(cast<llvm::PointerType>(ConvertType(E->getType())));
+ llvm::Value *Result = llvm::ConstantPointerNull::get(
+ cast<llvm::PointerType>(ConvertType(E->getType())));
if (const MemberExpr *ME =
dyn_cast<MemberExpr>(E->getArg(0)->IgnoreImpCasts())) {
>From 4532b8e295c426b687a622b60b7177451300f2b8 Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Wed, 7 Aug 2024 13:54:22 -0700
Subject: [PATCH 06/11] Use a visitor to retrieve the MemberExpr. It's
intentionally harsh and ignores pretty much everythings that may 'hide' the
underlying MemberExpr.
---
clang/lib/CodeGen/CGBuiltin.cpp | 47 +++++++++++++++++++++++++++----
clang/lib/Sema/SemaExpr.cpp | 50 +++++++++++++++++++++++++++++----
2 files changed, 87 insertions(+), 10 deletions(-)
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index a703d1173b9be2..2cba1971280b7f 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -27,6 +27,7 @@
#include "clang/AST/Decl.h"
#include "clang/AST/OSLog.h"
#include "clang/AST/OperationKinds.h"
+#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/TargetBuiltins.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/TargetOptions.h"
@@ -2536,6 +2537,45 @@ static RValue EmitHipStdParUnsupportedBuiltin(CodeGenFunction *CGF,
return RValue::get(CGF->Builder.CreateCall(UBF, Args));
}
+namespace {
+
+/// MemberExprVisitor - Find the MemberExpr through all of the casts, array
+/// subscripts, and unary ops. This intentionally avoids all of them because
+/// we're interested only in the MemberExpr to check if it's a flexible array
+/// member.
+class MemberExprVisitor
+ : public ConstStmtVisitor<MemberExprVisitor, const Expr *> {
+public:
+ //===--------------------------------------------------------------------===//
+ // Visitor Methods
+ //===--------------------------------------------------------------------===//
+
+ const Expr *Visit(const Expr *E) {
+ return ConstStmtVisitor<MemberExprVisitor, const Expr *>::Visit(E);
+ }
+ const Expr *VisitStmt(const Stmt *S) { return nullptr; }
+
+ const Expr *VisitMemberExpr(const MemberExpr *E) { return E; }
+
+ const Expr *VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
+ return Visit(E->getBase());
+ }
+ const Expr *VisitCastExpr(const CastExpr *E) {
+ return Visit(E->getSubExpr());
+ }
+ const Expr *VisitParenExpr(const ParenExpr *E) {
+ return Visit(E->getSubExpr());
+ }
+ const Expr *VisitUnaryAddrOf(const clang::UnaryOperator *E) {
+ return Visit(E->getSubExpr());
+ }
+ const Expr *VisitUnaryDeref(const clang::UnaryOperator *E) {
+ return Visit(E->getSubExpr());
+ }
+};
+
+} // anonymous namespace
+
RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
const CallExpr *E,
ReturnValueSlot ReturnValue) {
@@ -3567,15 +3607,12 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
llvm::Value *Result = llvm::ConstantPointerNull::get(
cast<llvm::PointerType>(ConvertType(E->getType())));
- if (const MemberExpr *ME =
- dyn_cast<MemberExpr>(E->getArg(0)->IgnoreImpCasts())) {
+ if (const Expr *Ptr = MemberExprVisitor().Visit(E->getArg(0))) {
+ const MemberExpr *ME = cast<MemberExpr>(Ptr);
bool IsFlexibleArrayMember = ME->isFlexibleArrayMemberLike(
getContext(), getLangOpts().getStrictFlexArraysLevel(),
/*IgnoreTemplateOrMacroSubstitution=*/false);
- // TODO: Probably have to handle horrible casting crap here.
-
- // FIXME: Emit a diagnostic?
if (!ME->HasSideEffects(getContext()) && IsFlexibleArrayMember &&
ME->getMemberDecl()->getType()->isCountAttributedType()) {
const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl());
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 048d0c4ae49726..8091af764f9b19 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -28,6 +28,7 @@
#include "clang/AST/OperationKinds.h"
#include "clang/AST/ParentMapContext.h"
#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/AST/StmtVisitor.h"
#include "clang/AST/Type.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/Builtins.h"
@@ -6410,6 +6411,45 @@ const FieldDecl *FindCountedByField(const FieldDecl *FD) {
return dyn_cast<FieldDecl>(CountDecl);
}
+namespace {
+
+/// MemberExprVisitor - Find the MemberExpr through all of the casts, array
+/// subscripts, and unary ops. This intentionally avoids all of them because
+/// we're interested only in the MemberExpr to check if it's a flexible array
+/// member.
+class MemberExprVisitor
+ : public ConstStmtVisitor<MemberExprVisitor, const Expr *> {
+public:
+ //===--------------------------------------------------------------------===//
+ // Visitor Methods
+ //===--------------------------------------------------------------------===//
+
+ const Expr *Visit(const Expr *E) {
+ return ConstStmtVisitor<MemberExprVisitor, const Expr *>::Visit(E);
+ }
+ const Expr *VisitStmt(const Stmt *S) { return nullptr; }
+
+ const Expr *VisitMemberExpr(const MemberExpr *E) { return E; }
+
+ const Expr *VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
+ return Visit(E->getBase());
+ }
+ const Expr *VisitCastExpr(const CastExpr *E) {
+ return Visit(E->getSubExpr());
+ }
+ const Expr *VisitParenExpr(const ParenExpr *E) {
+ return Visit(E->getSubExpr());
+ }
+ const Expr *VisitUnaryAddrOf(const UnaryOperator *E) {
+ return Visit(E->getSubExpr());
+ }
+ const Expr *VisitUnaryDeref(const UnaryOperator *E) {
+ return Visit(E->getSubExpr());
+ }
+};
+
+} // anonymous namespace
+
ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
MultiExprArg ArgExprs, SourceLocation RParenLoc,
Expr *ExecConfig, bool IsExecConfig,
@@ -6613,19 +6653,19 @@ ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
if (FunctionDecl *FDecl = dyn_cast_or_null<FunctionDecl>(NDecl);
FDecl && FDecl->getBuiltinID() == Builtin::BI__builtin_get_counted_by) {
- if (const MemberExpr *ME =
- dyn_cast<MemberExpr>(ArgExprs[0]->IgnoreImpCasts())) {
+ if (const Expr *Ptr = MemberExprVisitor().Visit(ArgExprs[0])) {
+ const MemberExpr *ME = cast<MemberExpr>(Ptr);
bool IsFlexibleArrayMember = ME->isFlexibleArrayMemberLike(
Context, getLangOpts().getStrictFlexArraysLevel(),
/*IgnoreTemplateOrMacroSubstitution=*/false);
- // TODO: Probably have to handle horrible casting crap here.
-
- // FIXME: Emit a diagnostic?
if (!ME->HasSideEffects(Context) && IsFlexibleArrayMember &&
ME->getMemberDecl()->getType()->isCountAttributedType()) {
const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl());
if (const FieldDecl *CountFD = FindCountedByField(FAMDecl)) {
+ // The builtin returns a 'size_t *', however 'size_t' might not be
+ // the type of the count field. Thus we create an explicit c-style
+ // cast to ensure the proper types going forward.
QualType PtrTy = Context.getPointerType(CountFD->getType());
Result = CStyleCastExpr::Create(
Context, PtrTy, VK_LValue, CK_BitCast, Result.get(), nullptr,
>From 5a74079039c39202711e0cc20c3412a05367d129 Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Wed, 7 Aug 2024 15:11:45 -0700
Subject: [PATCH 07/11] Add testcases.
---
clang/test/CodeGen/builtin-get-counted-by.c | 83 +++++++++++++++++++++
clang/test/Sema/builtin-get-counted-by.c | 22 ++++++
2 files changed, 105 insertions(+)
create mode 100644 clang/test/CodeGen/builtin-get-counted-by.c
create mode 100644 clang/test/Sema/builtin-get-counted-by.c
diff --git a/clang/test/CodeGen/builtin-get-counted-by.c b/clang/test/CodeGen/builtin-get-counted-by.c
new file mode 100644
index 00000000000000..8209db6a77111e
--- /dev/null
+++ b/clang/test/CodeGen/builtin-get-counted-by.c
@@ -0,0 +1,83 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 5
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -O2 -emit-llvm -o - %s | FileCheck %s --check-prefix=X86_64
+// RUN: %clang_cc1 -triple i386-unknown-unknown -O2 -emit-llvm -o - %s | FileCheck %s --check-prefix=I386
+
+struct s {
+ char x;
+ short count;
+ int array[] __attribute__((counted_by(count)));
+};
+
+// X86_64-LABEL: define dso_local noalias noundef ptr @test1(
+// X86_64-SAME: i32 noundef [[SIZE:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
+// X86_64-NEXT: [[ENTRY:.*:]]
+// X86_64-NEXT: [[CONV:%.*]] = sext i32 [[SIZE]] to i64
+// X86_64-NEXT: [[MUL:%.*]] = shl nsw i64 [[CONV]], 2
+// X86_64-NEXT: [[ADD:%.*]] = add nsw i64 [[MUL]], 4
+// X86_64-NEXT: [[CALL:%.*]] = tail call ptr @malloc(i64 noundef [[ADD]]) #[[ATTR3:[0-9]+]]
+// X86_64-NEXT: [[CONV1:%.*]] = trunc i32 [[SIZE]] to i16
+// X86_64-NEXT: [[DOT_COUNTED_BY_GEP:%.*]] = getelementptr inbounds i8, ptr [[CALL]], i64 2
+// X86_64-NEXT: store i16 [[CONV1]], ptr [[DOT_COUNTED_BY_GEP]], align 2, !tbaa [[TBAA2:![0-9]+]]
+// X86_64-NEXT: ret ptr [[CALL]]
+//
+// I386-LABEL: define dso_local noalias noundef ptr @test1(
+// I386-SAME: i32 noundef [[SIZE:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
+// I386-NEXT: [[ENTRY:.*:]]
+// I386-NEXT: [[MUL:%.*]] = shl i32 [[SIZE]], 2
+// I386-NEXT: [[ADD:%.*]] = add i32 [[MUL]], 4
+// I386-NEXT: [[CALL:%.*]] = tail call ptr @malloc(i32 noundef [[ADD]]) #[[ATTR3:[0-9]+]]
+// I386-NEXT: [[CONV:%.*]] = trunc i32 [[SIZE]] to i16
+// I386-NEXT: [[DOT_COUNTED_BY_GEP:%.*]] = getelementptr inbounds i8, ptr [[CALL]], i32 2
+// I386-NEXT: store i16 [[CONV]], ptr [[DOT_COUNTED_BY_GEP]], align 2, !tbaa [[TBAA3:![0-9]+]]
+// I386-NEXT: ret ptr [[CALL]]
+//
+struct s *test1(int size) {
+ struct s *p = __builtin_malloc(sizeof(struct s) + sizeof(int) * size);
+
+ *__builtin_get_counted_by(p->array) = size;
+ *__builtin_get_counted_by(&p->array[0]) = size;
+ return p;
+}
+
+struct z {
+ char x;
+ short count;
+ int array[];
+};
+
+// X86_64-LABEL: define dso_local noalias noundef ptr @test2(
+// X86_64-SAME: i32 noundef [[SIZE:%.*]]) local_unnamed_addr #[[ATTR2:[0-9]+]] {
+// X86_64-NEXT: [[ENTRY:.*:]]
+// X86_64-NEXT: [[CONV:%.*]] = sext i32 [[SIZE]] to i64
+// X86_64-NEXT: [[MUL:%.*]] = shl nsw i64 [[CONV]], 2
+// X86_64-NEXT: [[ADD:%.*]] = add nsw i64 [[MUL]], 4
+// X86_64-NEXT: [[CALL:%.*]] = tail call ptr @malloc(i64 noundef [[ADD]]) #[[ATTR3]]
+// X86_64-NEXT: ret ptr [[CALL]]
+//
+// I386-LABEL: define dso_local noalias noundef ptr @test2(
+// I386-SAME: i32 noundef [[SIZE:%.*]]) local_unnamed_addr #[[ATTR2:[0-9]+]] {
+// I386-NEXT: [[ENTRY:.*:]]
+// I386-NEXT: [[MUL:%.*]] = shl i32 [[SIZE]], 2
+// I386-NEXT: [[ADD:%.*]] = add i32 [[MUL]], 4
+// I386-NEXT: [[CALL:%.*]] = tail call ptr @malloc(i32 noundef [[ADD]]) #[[ATTR3]]
+// I386-NEXT: ret ptr [[CALL]]
+//
+struct z *test2(int size) {
+ struct z *p = __builtin_malloc(sizeof(struct z) + sizeof(int) * size);
+
+ if (__builtin_get_counted_by(&p->array[0]))
+ *__builtin_get_counted_by(&p->array[0]) = size;
+
+ return p;
+}
+//.
+// X86_64: [[TBAA2]] = !{[[META3:![0-9]+]], [[META3]], i64 0}
+// X86_64: [[META3]] = !{!"short", [[META4:![0-9]+]], i64 0}
+// X86_64: [[META4]] = !{!"omnipotent char", [[META5:![0-9]+]], i64 0}
+// X86_64: [[META5]] = !{!"Simple C/C++ TBAA"}
+//.
+// I386: [[TBAA3]] = !{[[META4:![0-9]+]], [[META4]], i64 0}
+// I386: [[META4]] = !{!"short", [[META5:![0-9]+]], i64 0}
+// I386: [[META5]] = !{!"omnipotent char", [[META6:![0-9]+]], i64 0}
+// I386: [[META6]] = !{!"Simple C/C++ TBAA"}
+//.
diff --git a/clang/test/Sema/builtin-get-counted-by.c b/clang/test/Sema/builtin-get-counted-by.c
new file mode 100644
index 00000000000000..18cef35b0509a1
--- /dev/null
+++ b/clang/test/Sema/builtin-get-counted-by.c
@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+struct fam_struct {
+ char x;
+ short count;
+ int array[] __attribute__((counted_by(count)));
+} *p;
+
+struct non_fam_struct {
+ char x;
+ short count;
+ int array[];
+} *q;
+
+void foo(int size) {
+ *__builtin_get_counted_by(p->array) = size;
+
+ if (__builtin_get_counted_by(q->array))
+ *__builtin_get_counted_by(q->array) = size;
+
+ *__builtin_get_counted_by(p->count) = size; // expected-error{{incompatible integer to pointer conversion passing 'short' to parameter of type 'void *'}}
+}
>From d9e9c6a879bf5fae9ec4453d41fe40abbeb865f9 Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Thu, 8 Aug 2024 16:21:35 -0700
Subject: [PATCH 08/11] Reformat
---
clang/lib/CodeGen/CGBuiltin.cpp | 4 ++--
clang/lib/Sema/SemaExpr.cpp | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 58fc0dfe45e1b0..de46c538fdcc30 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3610,8 +3610,8 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
if (const Expr *Ptr = MemberExprVisitor().Visit(E->getArg(0))) {
const MemberExpr *ME = cast<MemberExpr>(Ptr);
bool IsFlexibleArrayMember = ME->isFlexibleArrayMemberLike(
- getContext(), getLangOpts().getStrictFlexArraysLevel(),
- /*IgnoreTemplateOrMacroSubstitution=*/false);
+ getContext(), getLangOpts().getStrictFlexArraysLevel(),
+ /*IgnoreTemplateOrMacroSubstitution=*/false);
if (!ME->HasSideEffects(getContext()) && IsFlexibleArrayMember &&
ME->getMemberDecl()->getType()->isCountAttributedType()) {
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 33bc71d621ddd5..3b80bcfd3ab26d 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6656,8 +6656,8 @@ ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
if (const Expr *Ptr = MemberExprVisitor().Visit(ArgExprs[0])) {
const MemberExpr *ME = cast<MemberExpr>(Ptr);
bool IsFlexibleArrayMember = ME->isFlexibleArrayMemberLike(
- Context, getLangOpts().getStrictFlexArraysLevel(),
- /*IgnoreTemplateOrMacroSubstitution=*/false);
+ Context, getLangOpts().getStrictFlexArraysLevel(),
+ /*IgnoreTemplateOrMacroSubstitution=*/false);
if (!ME->HasSideEffects(Context) && IsFlexibleArrayMember &&
ME->getMemberDecl()->getType()->isCountAttributedType()) {
>From 10efe640a00520e2d074e7acfb65cb956a8ce1ac Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Thu, 8 Aug 2024 16:51:24 -0700
Subject: [PATCH 09/11] Combine the code to grab the MemberExpr, if it exists.
---
clang/include/clang/AST/Expr.h | 10 +++++--
clang/lib/AST/Expr.cpp | 43 ++++++++++++++++++++++++++++++
clang/lib/CodeGen/CGBuiltin.cpp | 46 ++-------------------------------
clang/lib/Sema/SemaExpr.cpp | 46 ++-------------------------------
4 files changed, 55 insertions(+), 90 deletions(-)
diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
index 5b813bfc2faf90..98524ffd7c02db 100644
--- a/clang/include/clang/AST/Expr.h
+++ b/clang/include/clang/AST/Expr.h
@@ -537,8 +537,8 @@ class Expr : public ValueStmt {
/// semantically correspond to a bool.
bool isKnownToHaveBooleanValue(bool Semantic = true) const;
- /// Check whether this array fits the idiom of a flexible array member,
- /// depending on the value of -fstrict-flex-array.
+ /// isFlexibleArrayMemberLike - Check whether this array fits the idiom of a
+ /// flexible array member, depending on the value of -fstrict-flex-array.
/// When IgnoreTemplateOrMacroSubstitution is set, it doesn't consider sizes
/// resulting from the substitution of a macro or a template as special sizes.
bool isFlexibleArrayMemberLike(
@@ -546,6 +546,12 @@ class Expr : public ValueStmt {
LangOptions::StrictFlexArraysLevelKind StrictFlexArraysLevel,
bool IgnoreTemplateOrMacroSubstitution = false) const;
+ /// getMemberExpr - Find the first MemberExpr of the Expr. This method
+ /// intentionally looks through all casts, array subscripts, and unary
+ /// operators to find an underlying MemberExpr. If one doesn't exist, it
+ /// returns a nullptr.
+ const MemberExpr *getMemberExpr() const;
+
/// isIntegerConstantExpr - Return the value if this expression is a valid
/// integer constant expression. If not a valid i-c-e, return std::nullopt
/// and fill in Loc (if specified) with the location of the invalid
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 9d5b8167d0ee62..3a5599fac1d156 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -222,6 +222,49 @@ bool Expr::isFlexibleArrayMemberLike(
IgnoreTemplateOrMacroSubstitution);
}
+namespace {
+
+/// MemberExprVisitor - Find the MemberExpr through all of the casts, array
+/// subscripts, and unary ops. This intentionally avoids all of them because
+/// we're interested only in the MemberExpr to check if it's a flexible array
+/// member.
+class MemberExprVisitor
+ : public ConstStmtVisitor<MemberExprVisitor, const Expr *> {
+public:
+ //===--------------------------------------------------------------------===//
+ // Visitor Methods
+ //===--------------------------------------------------------------------===//
+
+ const Expr *Visit(const Expr *E) {
+ return ConstStmtVisitor<MemberExprVisitor, const Expr *>::Visit(E);
+ }
+ const Expr *VisitStmt(const Stmt *S) { return nullptr; }
+
+ const Expr *VisitMemberExpr(const MemberExpr *E) { return E; }
+
+ const Expr *VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
+ return Visit(E->getBase());
+ }
+ const Expr *VisitCastExpr(const CastExpr *E) {
+ return Visit(E->getSubExpr());
+ }
+ const Expr *VisitParenExpr(const ParenExpr *E) {
+ return Visit(E->getSubExpr());
+ }
+ const Expr *VisitUnaryAddrOf(const UnaryOperator *E) {
+ return Visit(E->getSubExpr());
+ }
+ const Expr *VisitUnaryDeref(const UnaryOperator *E) {
+ return Visit(E->getSubExpr());
+ }
+};
+
+} // anonymous namespace
+
+const MemberExpr *Expr::getMemberExpr() const {
+ return dyn_cast_if_present<MemberExpr>(MemberExprVisitor().Visit(this));
+}
+
const ValueDecl *
Expr::getAsBuiltinConstantDeclRef(const ASTContext &Context) const {
Expr::EvalResult Eval;
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index de46c538fdcc30..95dd32eeee10cd 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -27,7 +27,6 @@
#include "clang/AST/Decl.h"
#include "clang/AST/OSLog.h"
#include "clang/AST/OperationKinds.h"
-#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/TargetBuiltins.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/TargetOptions.h"
@@ -2537,45 +2536,6 @@ static RValue EmitHipStdParUnsupportedBuiltin(CodeGenFunction *CGF,
return RValue::get(CGF->Builder.CreateCall(UBF, Args));
}
-namespace {
-
-/// MemberExprVisitor - Find the MemberExpr through all of the casts, array
-/// subscripts, and unary ops. This intentionally avoids all of them because
-/// we're interested only in the MemberExpr to check if it's a flexible array
-/// member.
-class MemberExprVisitor
- : public ConstStmtVisitor<MemberExprVisitor, const Expr *> {
-public:
- //===--------------------------------------------------------------------===//
- // Visitor Methods
- //===--------------------------------------------------------------------===//
-
- const Expr *Visit(const Expr *E) {
- return ConstStmtVisitor<MemberExprVisitor, const Expr *>::Visit(E);
- }
- const Expr *VisitStmt(const Stmt *S) { return nullptr; }
-
- const Expr *VisitMemberExpr(const MemberExpr *E) { return E; }
-
- const Expr *VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
- return Visit(E->getBase());
- }
- const Expr *VisitCastExpr(const CastExpr *E) {
- return Visit(E->getSubExpr());
- }
- const Expr *VisitParenExpr(const ParenExpr *E) {
- return Visit(E->getSubExpr());
- }
- const Expr *VisitUnaryAddrOf(const clang::UnaryOperator *E) {
- return Visit(E->getSubExpr());
- }
- const Expr *VisitUnaryDeref(const clang::UnaryOperator *E) {
- return Visit(E->getSubExpr());
- }
-};
-
-} // anonymous namespace
-
RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
const CallExpr *E,
ReturnValueSlot ReturnValue) {
@@ -3607,11 +3567,9 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
llvm::Value *Result = llvm::ConstantPointerNull::get(
cast<llvm::PointerType>(ConvertType(E->getType())));
- if (const Expr *Ptr = MemberExprVisitor().Visit(E->getArg(0))) {
- const MemberExpr *ME = cast<MemberExpr>(Ptr);
+ if (const MemberExpr *ME = E->getArg(0)->getMemberExpr()) {
bool IsFlexibleArrayMember = ME->isFlexibleArrayMemberLike(
- getContext(), getLangOpts().getStrictFlexArraysLevel(),
- /*IgnoreTemplateOrMacroSubstitution=*/false);
+ getContext(), getLangOpts().getStrictFlexArraysLevel());
if (!ME->HasSideEffects(getContext()) && IsFlexibleArrayMember &&
ME->getMemberDecl()->getType()->isCountAttributedType()) {
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 3b80bcfd3ab26d..45f540e417cd43 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -28,7 +28,6 @@
#include "clang/AST/OperationKinds.h"
#include "clang/AST/ParentMapContext.h"
#include "clang/AST/RecursiveASTVisitor.h"
-#include "clang/AST/StmtVisitor.h"
#include "clang/AST/Type.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/Builtins.h"
@@ -6411,45 +6410,6 @@ const FieldDecl *FindCountedByField(const FieldDecl *FD) {
return dyn_cast<FieldDecl>(CountDecl);
}
-namespace {
-
-/// MemberExprVisitor - Find the MemberExpr through all of the casts, array
-/// subscripts, and unary ops. This intentionally avoids all of them because
-/// we're interested only in the MemberExpr to check if it's a flexible array
-/// member.
-class MemberExprVisitor
- : public ConstStmtVisitor<MemberExprVisitor, const Expr *> {
-public:
- //===--------------------------------------------------------------------===//
- // Visitor Methods
- //===--------------------------------------------------------------------===//
-
- const Expr *Visit(const Expr *E) {
- return ConstStmtVisitor<MemberExprVisitor, const Expr *>::Visit(E);
- }
- const Expr *VisitStmt(const Stmt *S) { return nullptr; }
-
- const Expr *VisitMemberExpr(const MemberExpr *E) { return E; }
-
- const Expr *VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
- return Visit(E->getBase());
- }
- const Expr *VisitCastExpr(const CastExpr *E) {
- return Visit(E->getSubExpr());
- }
- const Expr *VisitParenExpr(const ParenExpr *E) {
- return Visit(E->getSubExpr());
- }
- const Expr *VisitUnaryAddrOf(const UnaryOperator *E) {
- return Visit(E->getSubExpr());
- }
- const Expr *VisitUnaryDeref(const UnaryOperator *E) {
- return Visit(E->getSubExpr());
- }
-};
-
-} // anonymous namespace
-
ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
MultiExprArg ArgExprs, SourceLocation RParenLoc,
Expr *ExecConfig, bool IsExecConfig,
@@ -6653,11 +6613,9 @@ ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
if (FunctionDecl *FDecl = dyn_cast_or_null<FunctionDecl>(NDecl);
FDecl && FDecl->getBuiltinID() == Builtin::BI__builtin_get_counted_by) {
- if (const Expr *Ptr = MemberExprVisitor().Visit(ArgExprs[0])) {
- const MemberExpr *ME = cast<MemberExpr>(Ptr);
+ if (const MemberExpr *ME = ArgExprs[0]->getMemberExpr()) {
bool IsFlexibleArrayMember = ME->isFlexibleArrayMemberLike(
- Context, getLangOpts().getStrictFlexArraysLevel(),
- /*IgnoreTemplateOrMacroSubstitution=*/false);
+ Context, getLangOpts().getStrictFlexArraysLevel());
if (!ME->HasSideEffects(Context) && IsFlexibleArrayMember &&
ME->getMemberDecl()->getType()->isCountAttributedType()) {
>From ad8fb9433cb935eec394dd7960d5bde52c792679 Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Fri, 9 Aug 2024 16:38:50 -0700
Subject: [PATCH 10/11] Move FindCountedByField into a central place.
---
clang/include/clang/AST/Decl.h | 4 ++++
clang/lib/AST/Decl.cpp | 13 +++++++++++++
clang/lib/CodeGen/CGBuiltin.cpp | 4 ++--
clang/lib/CodeGen/CGExpr.cpp | 18 +-----------------
clang/lib/CodeGen/CodeGenFunction.h | 4 ----
clang/lib/Sema/SemaExpr.cpp | 19 +------------------
6 files changed, 21 insertions(+), 41 deletions(-)
diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index 561a9d872acfb0..5535703ef906f4 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -3206,6 +3206,10 @@ class FieldDecl : public DeclaratorDecl, public Mergeable<FieldDecl> {
/// Set the C++11 in-class initializer for this member.
void setInClassInitializer(Expr *NewInit);
+ /// Find the FieldDecl specified in a FAM's "counted_by" attribute. Returns
+ /// \p nullptr if either the attribute or the field doesn't exist.
+ const FieldDecl *FindCountedByField() const;
+
private:
void setLazyInClassInitializer(LazyDeclStmtPtr NewInit);
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index d832ce4190ff1a..3f4cd1339b3205 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -4678,6 +4678,19 @@ void FieldDecl::printName(raw_ostream &OS, const PrintingPolicy &Policy) const {
DeclaratorDecl::printName(OS, Policy);
}
+const FieldDecl *FieldDecl::FindCountedByField() const {
+ const auto *CAT = getType()->getAs<CountAttributedType>();
+ if (!CAT)
+ return nullptr;
+
+ const auto *CountDRE = cast<DeclRefExpr>(CAT->getCountExpr());
+ const auto *CountDecl = CountDRE->getDecl();
+ if (const auto *IFD = dyn_cast<IndirectFieldDecl>(CountDecl))
+ CountDecl = IFD->getAnonField();
+
+ return dyn_cast<FieldDecl>(CountDecl);
+}
+
//===----------------------------------------------------------------------===//
// TagDecl Implementation
//===----------------------------------------------------------------------===//
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 95dd32eeee10cd..c4ec7af63da12c 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -989,7 +989,7 @@ CodeGenFunction::emitFlexibleArrayMemberSize(const Expr *E, unsigned Type,
// attribute.
return nullptr;
- const FieldDecl *CountedByFD = FindCountedByField(FAMDecl);
+ const FieldDecl *CountedByFD = FAMDecl->FindCountedByField();
if (!CountedByFD)
// Can't find the field referenced by the "counted_by" attribute.
return nullptr;
@@ -3574,7 +3574,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
if (!ME->HasSideEffects(getContext()) && IsFlexibleArrayMember &&
ME->getMemberDecl()->getType()->isCountAttributedType()) {
const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl());
- if (const FieldDecl *CountFD = FindCountedByField(FAMDecl))
+ if (const FieldDecl *CountFD = FAMDecl->FindCountedByField())
Result = GetCountedByFieldExprGEP(ME, FAMDecl, CountFD);
}
}
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 55cd95c08e3ffc..375bc911e0df1f 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1154,22 +1154,6 @@ llvm::Value *CodeGenFunction::EmitLoadOfCountedByField(
return nullptr;
}
-const FieldDecl *CodeGenFunction::FindCountedByField(const FieldDecl *FD) {
- if (!FD)
- return nullptr;
-
- const auto *CAT = FD->getType()->getAs<CountAttributedType>();
- if (!CAT)
- return nullptr;
-
- const auto *CountDRE = cast<DeclRefExpr>(CAT->getCountExpr());
- const auto *CountDecl = CountDRE->getDecl();
- if (const auto *IFD = dyn_cast<IndirectFieldDecl>(CountDecl))
- CountDecl = IFD->getAnonField();
-
- return dyn_cast<FieldDecl>(CountDecl);
-}
-
void CodeGenFunction::EmitBoundsCheck(const Expr *E, const Expr *Base,
llvm::Value *Index, QualType IndexType,
bool Accessed) {
@@ -4309,7 +4293,7 @@ LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E,
ME->isFlexibleArrayMemberLike(getContext(), StrictFlexArraysLevel) &&
ME->getMemberDecl()->getType()->isCountAttributedType()) {
const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl());
- if (const FieldDecl *CountFD = FindCountedByField(FAMDecl)) {
+ if (const FieldDecl *CountFD = FAMDecl->FindCountedByField()) {
if (std::optional<int64_t> Diff =
getOffsetDifferenceInBits(*this, CountFD, FAMDecl)) {
CharUnits OffsetDiff = CGM.getContext().toCharUnitsFromBits(*Diff);
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index e5f5b94bba54b0..dadf5838d35554 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -3305,10 +3305,6 @@ class CodeGenFunction : public CodeGenTypeCache {
const FieldDecl *FAMDecl,
uint64_t &Offset);
- /// Find the FieldDecl specified in a FAM's "counted_by" attribute. Returns
- /// \p nullptr if either the attribute or the field doesn't exist.
- const FieldDecl *FindCountedByField(const FieldDecl *FD);
-
llvm::Value *GetCountedByFieldExprGEP(const Expr *Base,
const FieldDecl *FAMDecl,
const FieldDecl *CountDecl);
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 45f540e417cd43..202ce7abc10991 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6390,26 +6390,9 @@ ExprResult Sema::ActOnCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
currentEvaluationContext().ReferenceToConsteval.erase(DRE);
}
}
-
return Call;
}
-const FieldDecl *FindCountedByField(const FieldDecl *FD) {
- if (!FD)
- return nullptr;
-
- const auto *CAT = FD->getType()->getAs<CountAttributedType>();
- if (!CAT)
- return nullptr;
-
- const auto *CountDRE = cast<DeclRefExpr>(CAT->getCountExpr());
- const auto *CountDecl = CountDRE->getDecl();
- if (const auto *IFD = dyn_cast<IndirectFieldDecl>(CountDecl))
- CountDecl = IFD->getAnonField();
-
- return dyn_cast<FieldDecl>(CountDecl);
-}
-
ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
MultiExprArg ArgExprs, SourceLocation RParenLoc,
Expr *ExecConfig, bool IsExecConfig,
@@ -6620,7 +6603,7 @@ ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
if (!ME->HasSideEffects(Context) && IsFlexibleArrayMember &&
ME->getMemberDecl()->getType()->isCountAttributedType()) {
const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl());
- if (const FieldDecl *CountFD = FindCountedByField(FAMDecl)) {
+ if (const FieldDecl *CountFD = FAMDecl->FindCountedByField()) {
// The builtin returns a 'size_t *', however 'size_t' might not be
// the type of the count field. Thus we create an explicit c-style
// cast to ensure the proper types going forward.
>From 7c1facf8378ad3733c0ec6b74cc17e4429c64cda Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Wed, 14 Aug 2024 12:11:27 -0700
Subject: [PATCH 11/11] Use CustomTypeChecking for the builtin. It allows us
explicitly to set the return type based on the 'count' field's type.
---
clang/include/clang/Basic/Builtins.td | 4 +-
.../clang/Basic/DiagnosticSemaKinds.td | 5 +++
clang/include/clang/Sema/Sema.h | 2 +
clang/lib/AST/Expr.cpp | 5 ---
clang/lib/Sema/SemaChecking.cpp | 42 +++++++++++++++++++
clang/lib/Sema/SemaExpr.cpp | 29 +------------
6 files changed, 53 insertions(+), 34 deletions(-)
diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td
index 254cd157d5f9d0..33f26ebab7f392 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/clang/include/clang/Basic/Builtins.td
@@ -4777,6 +4777,6 @@ def ArithmeticFence : LangBuiltin<"ALL_LANGUAGES"> {
def GetCountedBy : Builtin {
let Spellings = ["__builtin_get_counted_by"];
- let Attributes = [NoThrow];
- let Prototype = "size_t*(void*)";
+ let Attributes = [NoThrow, CustomTypeChecking];
+ let Prototype = "int(...)";
}
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 5cdf36660b2a66..e72d5eaf742828 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6624,6 +6624,11 @@ def warn_counted_by_attr_elt_type_unknown_size :
Warning<err_counted_by_attr_pointee_unknown_size.Summary>,
InGroup<BoundsSafetyCountedByEltTyUnknownSize>;
+def err_builtin_get_counted_by_has_side_effects : Error<
+ "__builtin_get_counted_by cannot have side-effects">;
+def err_builtin_get_counted_by_must_be_pointer : Error<
+ "__builtin_get_counted_by argument must be a pointer">;
+
let CategoryName = "ARC Semantic Issue" in {
// ARC-mode diagnostics.
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index b7bd6c2433efd6..bdf27ea40ef318 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -2545,6 +2545,8 @@ class Sema final : public SemaBase {
bool BuiltinNonDeterministicValue(CallExpr *TheCall);
+ bool BuiltinGetCountedBy(CallExpr *TheCall);
+
// Matrix builtin handling.
ExprResult BuiltinMatrixTranspose(CallExpr *TheCall, ExprResult CallResult);
ExprResult BuiltinMatrixColumnMajorLoad(CallExpr *TheCall,
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 3a5599fac1d156..1bbff09f1d55ec 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -235,11 +235,6 @@ class MemberExprVisitor
// Visitor Methods
//===--------------------------------------------------------------------===//
- const Expr *Visit(const Expr *E) {
- return ConstStmtVisitor<MemberExprVisitor, const Expr *>::Visit(E);
- }
- const Expr *VisitStmt(const Stmt *S) { return nullptr; }
-
const Expr *VisitMemberExpr(const MemberExpr *E) { return E; }
const Expr *VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index ee143381cf4f79..1d8a6acce5d916 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2911,6 +2911,10 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
}
break;
}
+ case Builtin::BI__builtin_get_counted_by:
+ if (BuiltinGetCountedBy(TheCall))
+ return ExprError();
+ break;
}
if (getLangOpts().HLSL && HLSL().CheckBuiltinFunctionCall(BuiltinID, TheCall))
@@ -5503,6 +5507,44 @@ bool Sema::BuiltinSetjmp(CallExpr *TheCall) {
return false;
}
+bool Sema::BuiltinGetCountedBy(CallExpr *TheCall) {
+ if (checkArgCount(TheCall, 1))
+ return true;
+
+ ExprResult ArgRes = UsualUnaryConversions(TheCall->getArg(0));
+ if (ArgRes.isInvalid())
+ return true;
+
+ const Expr *Arg = ArgRes.get();
+ if (!isa<PointerType>(Arg->getType()))
+ return Diag(Arg->getBeginLoc(),
+ diag::err_builtin_get_counted_by_must_be_pointer)
+ << Arg->getSourceRange();
+
+ if (Arg->HasSideEffects(Context))
+ return Diag(Arg->getBeginLoc(),
+ diag::err_builtin_get_counted_by_has_side_effects)
+ << Arg->getSourceRange();
+
+ // Use 'void *' as the default return type. If the argument doesn't have the
+ // 'counted_by' attribute, it'll return a "nullptr."
+ TheCall->setType(Context.VoidPtrTy);
+
+ if (const MemberExpr *ME = Arg->getMemberExpr();
+ ME &&
+ ME->isFlexibleArrayMemberLike(Context,
+ getLangOpts().getStrictFlexArraysLevel()) &&
+ ME->getMemberDecl()->getType()->isCountAttributedType()) {
+ if (const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl()))
+ if (const FieldDecl *CountFD = FAMDecl->FindCountedByField())
+ // The proper return type should be a pointer to the type of the
+ // counted_by's 'count' field.
+ TheCall->setType(Context.getPointerType(CountFD->getType()));
+ }
+
+ return false;
+}
+
namespace {
class UncoveredArgHandler {
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 202ce7abc10991..14e96d5ef4cd11 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6591,33 +6591,8 @@ ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
VK_PRValue, RParenLoc, CurFPFeatureOverrides());
}
- Result = BuildResolvedCallExpr(Fn, NDecl, LParenLoc, ArgExprs, RParenLoc,
- ExecConfig, IsExecConfig);
-
- if (FunctionDecl *FDecl = dyn_cast_or_null<FunctionDecl>(NDecl);
- FDecl && FDecl->getBuiltinID() == Builtin::BI__builtin_get_counted_by) {
- if (const MemberExpr *ME = ArgExprs[0]->getMemberExpr()) {
- bool IsFlexibleArrayMember = ME->isFlexibleArrayMemberLike(
- Context, getLangOpts().getStrictFlexArraysLevel());
-
- if (!ME->HasSideEffects(Context) && IsFlexibleArrayMember &&
- ME->getMemberDecl()->getType()->isCountAttributedType()) {
- const FieldDecl *FAMDecl = dyn_cast<FieldDecl>(ME->getMemberDecl());
- if (const FieldDecl *CountFD = FAMDecl->FindCountedByField()) {
- // The builtin returns a 'size_t *', however 'size_t' might not be
- // the type of the count field. Thus we create an explicit c-style
- // cast to ensure the proper types going forward.
- QualType PtrTy = Context.getPointerType(CountFD->getType());
- Result = CStyleCastExpr::Create(
- Context, PtrTy, VK_LValue, CK_BitCast, Result.get(), nullptr,
- FPOptionsOverride(), Context.CreateTypeSourceInfo(PtrTy),
- LParenLoc, RParenLoc);
- }
- }
- }
- }
-
- return Result;
+ return BuildResolvedCallExpr(Fn, NDecl, LParenLoc, ArgExprs, RParenLoc,
+ ExecConfig, IsExecConfig);
}
Expr *Sema::BuildBuiltinCallExpr(SourceLocation Loc, Builtin::ID Id,
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