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Repository:
rG LLVM Github Monorepo
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https://reviews.llvm.org/D126864/new/
https://reviews.llvm.org/D126864
Files:
clang/docs/ClangCommandLineReference.rst
clang/docs/ReleaseNotes.rst
clang/include/clang/AST/Expr.h
clang/include/clang/Basic/LangOptions.def
clang/include/clang/Driver/Options.td
clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
clang/lib/AST/Expr.cpp
clang/lib/AST/ExprConstant.cpp
clang/lib/CodeGen/CGExpr.cpp
clang/lib/Driver/ToolChains/Clang.cpp
clang/lib/Sema/SemaChecking.cpp
clang/lib/StaticAnalyzer/Core/MemRegion.cpp
clang/test/CodeGen/bounds-checking-fma.c
clang/test/CodeGen/bounds-checking.c
clang/test/CodeGen/object-size-flex-array.c
clang/test/CodeGenObjC/ubsan-array-bounds.m
clang/test/Sema/array-bounds-ptr-arith.c
clang/test/SemaCXX/array-bounds-strict-flex-arrays.cpp
Index: clang/test/SemaCXX/array-bounds-strict-flex-arrays.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/array-bounds-strict-flex-arrays.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -verify -fstrict-flex-arrays=3 %s
+
+// We cannot know for sure the size of a flexible array.
+void test() {
+ struct {
+ int f;
+ int a[];
+ } s2;
+ s2.a[2] = 0; // no-warning
+}
+
+// Under -fstrict-flex-arrays `a` is not a flexible array.
+void test1() {
+ struct {
+ int f;
+ int a[1]; // expected-note {{declared here}}
+ } s2;
+ s2.a[2] = 0; // expected-warning 1 {{array index 2 is past the end of the array (which contains 1 element)}}
+}
Index: clang/test/Sema/array-bounds-ptr-arith.c
===================================================================
--- clang/test/Sema/array-bounds-ptr-arith.c
+++ clang/test/Sema/array-bounds-ptr-arith.c
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -verify -Warray-bounds-pointer-arithmetic %s
+// RUN: %clang_cc1 -verify -Warray-bounds-pointer-arithmetic -fstrict-flex-arrays=1 %s
// Test case from PR10615
struct ext2_super_block{
@@ -12,40 +12,3 @@
{
return (void *)es->s_uuid + 80; // expected-warning {{refers past the end of the array}}
}
-
-// Test case reduced from PR11594
-struct S { int n; };
-void pr11594(struct S *s) {
- int a[10];
- int *p = a - s->n;
-}
-
-// Test case reduced from <rdar://problem/11387038>. This resulted in
-// an assertion failure because of the typedef instead of an explicit
-// constant array type.
-struct RDar11387038 {};
-typedef struct RDar11387038 RDar11387038Array[1];
-struct RDar11387038_Table {
- RDar11387038Array z;
-};
-typedef struct RDar11387038_Table * TPtr;
-typedef TPtr *TabHandle;
-struct RDar11387038_B { TabHandle x; };
-typedef struct RDar11387038_B RDar11387038_B;
-
-void radar11387038(void) {
- RDar11387038_B *pRDar11387038_B;
- struct RDar11387038* y = &(*pRDar11387038_B->x)->z[4];
-}
-
-void pr51682 (void) {
- int arr [1];
- switch (0) {
- case 0:
- break;
- case 1:
- asm goto (""::"r"(arr[42] >> 1)::failed); // no-warning
- break;
- }
-failed:;
-}
Index: clang/test/CodeGenObjC/ubsan-array-bounds.m
===================================================================
--- clang/test/CodeGenObjC/ubsan-array-bounds.m
+++ clang/test/CodeGenObjC/ubsan-array-bounds.m
@@ -14,46 +14,3 @@
return FA1->chars[1];
// CHECK: }
}
-
-@interface FlexibleArray2 {
-@public
- char chars[0];
-}
-@end
-@implementation FlexibleArray2 {
-@public
- char chars2[0];
-}
-@end
-
-// CHECK-LABEL: test_FlexibleArray2_1
-char test_FlexibleArray2_1(FlexibleArray2 *FA2) {
- // CHECK: !nosanitize
- return FA2->chars[1];
- // CHECK: }
-}
-
-// CHECK-LABEL: test_FlexibleArray2_2
-char test_FlexibleArray2_2(FlexibleArray2 *FA2) {
- // CHECK-NOT: !nosanitize
- return FA2->chars2[1];
- // CHECK: }
-}
-
-@interface FlexibleArray3 {
-@public
- char chars[0];
-}
-@end
-@implementation FlexibleArray3 {
-@public
- int i;
-}
-@end
-
-// CHECK-LABEL: test_FlexibleArray3
-char test_FlexibleArray3(FlexibleArray3 *FA3) {
- // CHECK: !nosanitize
- return FA3->chars[1];
- // CHECK: }
-}
Index: clang/test/CodeGen/object-size-flex-array.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/object-size-flex-array.c
@@ -0,0 +1,106 @@
+// RUN: %clang -fstrict-flex-arrays=3 -target x86_64-apple-darwin -S -emit-llvm %s -o - 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-STRICT-3 %s
+// RUN: %clang -fstrict-flex-arrays=2 -target x86_64-apple-darwin -S -emit-llvm %s -o - 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-STRICT-2 %s
+// RUN: %clang -fstrict-flex-arrays=1 -target x86_64-apple-darwin -S -emit-llvm %s -o - 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-STRICT-1 %s
+// RUN: %clang -fstrict-flex-arrays=0 -target x86_64-apple-darwin -S -emit-llvm %s -o - 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-STRICT-0 %s
+
+#define OBJECT_SIZE_BUILTIN __builtin_object_size
+
+typedef struct {
+ float f;
+ double c[];
+} foo_t;
+
+typedef struct {
+ float f;
+ double c[0];
+} foo0_t;
+
+typedef struct {
+ float f;
+ double c[1];
+} foo1_t;
+
+typedef struct {
+ float f;
+ double c[2];
+} foo2_t;
+
+// CHECK-LABEL: @bar
+unsigned bar(foo_t *f) {
+ // CHECK-STRICT-0: ret i32 %
+ // CHECK-STRICT-1: ret i32 %
+ // CHECK-STRICT-2: ret i32 %
+ // CHECK-STRICT-3: ret i32 %
+ return OBJECT_SIZE_BUILTIN(f->c, 1);
+}
+
+// CHECK-LABEL: @bar0
+unsigned bar0(foo0_t *f) {
+ // CHECK-STRICT-0: ret i32 %
+ // CHECK-STRICT-1: ret i32 %
+ // CHECK-STRICT-2: ret i32 %
+ // CHECK-STRICT-3: ret i32 0
+ return OBJECT_SIZE_BUILTIN(f->c, 1);
+}
+
+// CHECK-LABEL: @bar1
+unsigned bar1(foo1_t *f) {
+ // CHECK-STRICT-0: ret i32 %
+ // CHECK-STRICT-1: ret i32 %
+ // CHECK-STRICT-2: ret i32 8
+ // CHECK-STRICT-3: ret i32 8
+ return OBJECT_SIZE_BUILTIN(f->c, 1);
+}
+
+// CHECK-LABEL: @bar2
+unsigned bar2(foo2_t *f) {
+ // CHECK-STRICT-0: ret i32 %
+ // CHECK-STRICT-1: ret i32 16
+ // CHECK-STRICT-2: ret i32 16
+ // CHECK-STRICT-3: ret i32 16
+ return OBJECT_SIZE_BUILTIN(f->c, 1);
+}
+
+// Also checks for non-trailing flex-array like members
+
+typedef struct {
+ double c[0];
+ float f;
+} foofoo0_t;
+
+typedef struct {
+ double c[1];
+ float f;
+} foofoo1_t;
+
+typedef struct {
+ double c[2];
+ float f;
+} foofoo2_t;
+
+// CHECK-LABEL: @babar0
+unsigned babar0(foofoo0_t *f) {
+ // CHECK-STRICT-0: ret i32 0
+ // CHECK-STRICT-1: ret i32 0
+ // CHECK-STRICT-2: ret i32 0
+ // CHECK-STRICT-3: ret i32 0
+ return OBJECT_SIZE_BUILTIN(f->c, 1);
+}
+
+// CHECK-LABEL: @babar1
+unsigned babar1(foofoo1_t *f) {
+ // CHECK-STRICT-0: ret i32 8
+ // CHECK-STRICT-1: ret i32 8
+ // CHECK-STRICT-2: ret i32 8
+ // CHECK-STRICT-3: ret i32 8
+ return OBJECT_SIZE_BUILTIN(f->c, 1);
+}
+
+// CHECK-LABEL: @babar2
+unsigned babar2(foofoo2_t *f) {
+ // CHECK-STRICT-0: ret i32 16
+ // CHECK-STRICT-1: ret i32 16
+ // CHECK-STRICT-2: ret i32 16
+ // CHECK-STRICT-3: ret i32 16
+ return OBJECT_SIZE_BUILTIN(f->c, 1);
+}
Index: clang/test/CodeGen/bounds-checking.c
===================================================================
--- clang/test/CodeGen/bounds-checking.c
+++ clang/test/CodeGen/bounds-checking.c
@@ -35,8 +35,9 @@
// CHECK-LABEL: define {{.*}} @f4
int f4(union U *u, int i) {
- // a and b are treated as flexible array members.
- // CHECK-NOT: @llvm.ubsantrap
+ // a and b bounds are treated as flexible array members, but they are inside a union
+ // and that prevent them from being considered as flexible array members.
+ // NONLOCAL: @llvm.ubsantrap
return u->a[i] + u->b[i];
// CHECK: }
}
Index: clang/test/CodeGen/bounds-checking-fma.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/bounds-checking-fma.c
@@ -0,0 +1,42 @@
+// REQUIRES: x86-registered-target
+// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fsanitize=array-bounds %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-0
+// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fsanitize=array-bounds -fstrict-flex-arrays=1 %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-1
+// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fsanitize=array-bounds -fstrict-flex-arrays=2 %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-2
+
+// Before flexible array member was added to C99, many projects use a
+// one-element array as the last emember of a structure as an alternative.
+// E.g. https://github.com/python/cpython/issues/94250
+// Suppress such errors with -fstrict-flex-arrays=0.
+struct One {
+ int a[1];
+};
+struct Two {
+ int a[2];
+};
+struct Three {
+ int a[3];
+};
+
+// CHECK-LABEL: define {{.*}} @test_one(
+int test_one(struct One *p, int i) {
+ // CHECK-STRICT-0-NOT: @__ubsan
+ // CHECK-STRICT-1-NOT: @__ubsan
+ // CHECK-STRICT-2: call void @__ubsan_handle_out_of_bounds_abort(
+ return p->a[i] + (p->a)[i];
+}
+
+// CHECK-LABEL: define {{.*}} @test_two(
+int test_two(struct Two *p, int i) {
+ // CHECK-STRICT-0: call void @__ubsan_handle_out_of_bounds_abort(
+ // CHECK-STRICT-1: call void @__ubsan_handle_out_of_bounds_abort(
+ // CHECK-STRICT-2: call void @__ubsan_handle_out_of_bounds_abort(
+ return p->a[i] + (p->a)[i];
+}
+
+// CHECK-LABEL: define {{.*}} @test_three(
+int test_three(struct Three *p, int i) {
+ // CHECK-STRICT-0: call void @__ubsan_handle_out_of_bounds_abort(
+ // CHECK-STRICT-1: call void @__ubsan_handle_out_of_bounds_abort(
+ // CHECK-STRICT-2: call void @__ubsan_handle_out_of_bounds_abort(
+ return p->a[i] + (p->a)[i];
+}
Index: clang/lib/StaticAnalyzer/Core/MemRegion.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/MemRegion.cpp
+++ clang/lib/StaticAnalyzer/Core/MemRegion.cpp
@@ -789,6 +789,9 @@
if (isa<IncompleteArrayType>(AT))
return true;
+ if (getContext().getLangOpts().StrictFlexArrays)
+ return false;
+
if (const auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
const llvm::APInt &Size = CAT->getSize();
if (Size.isZero())
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -15716,53 +15716,6 @@
<< TRange << Op->getSourceRange();
}
-/// Check whether this array fits the idiom of a size-one tail padded
-/// array member of a struct.
-///
-/// We avoid emitting out-of-bounds access warnings for such arrays as they are
-/// commonly used to emulate flexible arrays in C89 code.
-static bool IsTailPaddedMemberArray(Sema &S, const llvm::APInt &Size,
- const NamedDecl *ND) {
- if (Size != 1 || !ND) return false;
-
- const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
- if (!FD) return false;
-
- // Don't consider sizes resulting from macro expansions or template argument
- // substitution to form C89 tail-padded arrays.
-
- TypeSourceInfo *TInfo = FD->getTypeSourceInfo();
- while (TInfo) {
- TypeLoc TL = TInfo->getTypeLoc();
- // Look through typedefs.
- if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) {
- const TypedefNameDecl *TDL = TTL.getTypedefNameDecl();
- TInfo = TDL->getTypeSourceInfo();
- continue;
- }
- if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) {
- const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr());
- if (!SizeExpr || SizeExpr->getExprLoc().isMacroID())
- return false;
- }
- break;
- }
-
- const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
- if (!RD) return false;
- if (RD->isUnion()) return false;
- if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
- if (!CRD->isStandardLayout()) return false;
- }
-
- // See if this is the last field decl in the record.
- const Decl *D = FD;
- while ((D = D->getNextDeclInContext()))
- if (isa<FieldDecl>(D))
- return false;
- return true;
-}
-
void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
const ArraySubscriptExpr *ASE,
bool AllowOnePastEnd, bool IndexNegated) {
@@ -15915,10 +15868,9 @@
if (AllowOnePastEnd ? index.ule(size) : index.ult(size))
return;
- // Also don't warn for arrays of size 1 which are members of some
- // structure. These are often used to approximate flexible arrays in C89
- // code.
- if (IsTailPaddedMemberArray(*this, size, ND))
+ // Also don't warn for flexible array members.
+ if (BaseExpr->isFlexibleArrayMember(Context,
+ getLangOpts().StrictFlexArrays))
return;
// Suppress the warning if the subscript expression (as identified by the
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -6221,6 +6221,8 @@
Args.AddLastArg(CmdArgs, options::OPT_funroll_loops,
options::OPT_fno_unroll_loops);
+ Args.AddLastArg(CmdArgs, options::OPT_fstrict_flex_arrays_EQ);
+
Args.AddLastArg(CmdArgs, options::OPT_pthread);
if (Args.hasFlag(options::OPT_mspeculative_load_hardening,
Index: clang/lib/CodeGen/CGExpr.cpp
===================================================================
--- clang/lib/CodeGen/CGExpr.cpp
+++ clang/lib/CodeGen/CGExpr.cpp
@@ -875,44 +875,6 @@
}
}
-/// Determine whether this expression refers to a flexible array member in a
-/// struct. We disable array bounds checks for such members.
-static bool isFlexibleArrayMemberExpr(const Expr *E) {
- // For compatibility with existing code, we treat arrays of length 0 or
- // 1 as flexible array members.
- // FIXME: This is inconsistent with the warning code in SemaChecking. Unify
- // the two mechanisms.
- const ArrayType *AT = E->getType()->castAsArrayTypeUnsafe();
- if (const auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
- // FIXME: Sema doesn't treat [1] as a flexible array member if the bound
- // was produced by macro expansion.
- if (CAT->getSize().ugt(1))
- return false;
- } else if (!isa<IncompleteArrayType>(AT))
- return false;
-
- E = E->IgnoreParens();
-
- // A flexible array member must be the last member in the class.
- if (const auto *ME = dyn_cast<MemberExpr>(E)) {
- // FIXME: If the base type of the member expr is not FD->getParent(),
- // this should not be treated as a flexible array member access.
- if (const auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
- // FIXME: Sema doesn't treat a T[1] union member as a flexible array
- // member, only a T[0] or T[] member gets that treatment.
- if (FD->getParent()->isUnion())
- return true;
- RecordDecl::field_iterator FI(
- DeclContext::decl_iterator(const_cast<FieldDecl *>(FD)));
- return ++FI == FD->getParent()->field_end();
- }
- } else if (const auto *IRE = dyn_cast<ObjCIvarRefExpr>(E)) {
- return IRE->getDecl()->getNextIvar() == nullptr;
- }
-
- return false;
-}
-
llvm::Value *CodeGenFunction::LoadPassedObjectSize(const Expr *E,
QualType EltTy) {
ASTContext &C = getContext();
@@ -954,8 +916,11 @@
/// If Base is known to point to the start of an array, return the length of
/// that array. Return 0 if the length cannot be determined.
-static llvm::Value *getArrayIndexingBound(
- CodeGenFunction &CGF, const Expr *Base, QualType &IndexedType) {
+static llvm::Value *getArrayIndexingBound(CodeGenFunction &CGF,
+ const Expr *Base,
+ QualType &IndexedType,
+ ASTContext &Context,
+ int StrictFlexArraysLevel) {
// For the vector indexing extension, the bound is the number of elements.
if (const VectorType *VT = Base->getType()->getAs<VectorType>()) {
IndexedType = Base->getType();
@@ -966,7 +931,8 @@
if (const auto *CE = dyn_cast<CastExpr>(Base)) {
if (CE->getCastKind() == CK_ArrayToPointerDecay &&
- !isFlexibleArrayMemberExpr(CE->getSubExpr())) {
+ !CE->getSubExpr()->IgnoreParens()->isFlexibleArrayMember(
+ Context, std::max(StrictFlexArraysLevel, 1))) {
IndexedType = CE->getSubExpr()->getType();
const ArrayType *AT = IndexedType->castAsArrayTypeUnsafe();
if (const auto *CAT = dyn_cast<ConstantArrayType>(AT))
@@ -994,7 +960,8 @@
SanitizerScope SanScope(this);
QualType IndexedType;
- llvm::Value *Bound = getArrayIndexingBound(*this, Base, IndexedType);
+ llvm::Value *Bound = getArrayIndexingBound(
+ *this, Base, IndexedType, getContext(), getLangOpts().StrictFlexArrays);
if (!Bound)
return;
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -11592,9 +11592,16 @@
// conservative with the last element in structs (if it's an array), so our
// current behavior is more compatible than an explicit list approach would
// be.
+ int StrictFlexArraysLevel = Ctx.getLangOpts().StrictFlexArrays;
return LVal.InvalidBase &&
Designator.Entries.size() == Designator.MostDerivedPathLength &&
Designator.MostDerivedIsArrayElement &&
+ (Designator.isMostDerivedAnUnsizedArray() ||
+ (Designator.getMostDerivedArraySize() == 0 &&
+ StrictFlexArraysLevel < 3) ||
+ (Designator.getMostDerivedArraySize() == 1 &&
+ StrictFlexArraysLevel < 2) ||
+ StrictFlexArraysLevel == 0) &&
isDesignatorAtObjectEnd(Ctx, LVal);
}
Index: clang/lib/AST/Expr.cpp
===================================================================
--- clang/lib/AST/Expr.cpp
+++ clang/lib/AST/Expr.cpp
@@ -203,6 +203,91 @@
return false;
}
+bool Expr::isFlexibleArrayMember(ASTContext &Ctx,
+ int StrictFlexArraysLevel) const {
+ const NamedDecl *ND = nullptr;
+ if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(this))
+ ND = DRE->getDecl();
+ if (const MemberExpr *ME = dyn_cast<MemberExpr>(this))
+ ND = ME->getMemberDecl();
+ if (const ObjCIvarRefExpr *RE = dyn_cast<ObjCIvarRefExpr>(this))
+ ND = RE->getDecl();
+ if (!ND)
+ return false;
+
+ const ConstantArrayType *ArrayTy = Ctx.getAsConstantArrayType(getType());
+
+ const Type *BaseType =
+ ArrayTy == nullptr ? nullptr : ArrayTy->getElementType().getTypePtr();
+ bool IsUnboundedArray = (BaseType == nullptr);
+
+ if (!IsUnboundedArray) {
+ llvm::APInt Size = ArrayTy->getSize();
+
+ switch (StrictFlexArraysLevel) {
+ case 3:
+ return false;
+ case 2:
+ if (Size != 0)
+ return false;
+ break;
+ case 1:
+ if (Size.ugt(1))
+ return false;
+ break;
+ case 0:
+ break;
+ default:
+ llvm_unreachable("Invalid strict flex arrays level");
+ }
+ }
+
+ const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
+ if (!FD)
+ return false;
+
+ // Don't consider sizes resulting from macro expansions or template argument
+ // substitution to form C89 tail-padded arrays.
+
+ TypeSourceInfo *TInfo = FD->getTypeSourceInfo();
+ while (TInfo) {
+ TypeLoc TL = TInfo->getTypeLoc();
+ // Look through typedefs.
+ if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) {
+ const TypedefNameDecl *TDL = TTL.getTypedefNameDecl();
+ TInfo = TDL->getTypeSourceInfo();
+ continue;
+ }
+ if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) {
+ const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr());
+ if (!SizeExpr || SizeExpr->getExprLoc().isMacroID())
+ return false;
+ }
+ break;
+ }
+
+ const ObjCInterfaceDecl *ID =
+ dyn_cast<ObjCInterfaceDecl>(FD->getDeclContext());
+ const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
+ if (RD) {
+ if (RD->isUnion())
+ return false;
+ if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
+ if (!CRD->isStandardLayout())
+ return false;
+ }
+ } else if (!ID)
+ return false;
+
+ // See if this is the last field decl in the record.
+ const Decl *D = FD;
+ while ((D = D->getNextDeclInContext()))
+ if (isa<FieldDecl>(D))
+ return false;
+
+ return true;
+}
+
const ValueDecl *
Expr::getAsBuiltinConstantDeclRef(const ASTContext &Context) const {
Expr::EvalResult Eval;
Index: clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
===================================================================
--- clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
+++ clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
@@ -1364,6 +1364,7 @@
~MemRegionManager();
ASTContext &getContext() { return Ctx; }
+ const ASTContext &getContext() const { return Ctx; }
llvm::BumpPtrAllocator &getAllocator() { return A; }
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -1140,6 +1140,12 @@
def fapple_kext : Flag<["-"], "fapple-kext">, Group<f_Group>, Flags<[CC1Option]>,
HelpText<"Use Apple's kernel extensions ABI">,
MarshallingInfoFlag<LangOpts<"AppleKext">>;
+def fstrict_flex_arrays_EQ : Joined<["-"], "fstrict-flex-arrays=">,Group<f_Group>,
+ MetaVarName<"<n>">, Values<"0,1,2,3">,
+ LangOpts<"StrictFlexArrays">,
+ Flags<[CC1Option]>,
+ HelpText<"Enable optimizations based on the strict definition of flexible arrays">,
+ MarshallingInfoInt<LangOpts<"StrictFlexArrays">>;
defm apple_pragma_pack : BoolFOption<"apple-pragma-pack",
LangOpts<"ApplePragmaPack">, DefaultFalse,
PosFlag<SetTrue, [CC1Option], "Enable Apple gcc-compatible #pragma pack handling">,
Index: clang/include/clang/Basic/LangOptions.def
===================================================================
--- clang/include/clang/Basic/LangOptions.def
+++ clang/include/clang/Basic/LangOptions.def
@@ -424,6 +424,7 @@
LANGOPT(RegisterStaticDestructors, 1, 1, "Register C++ static destructors")
LANGOPT(MatrixTypes, 1, 0, "Enable or disable the builtin matrix type")
+LANGOPT(StrictFlexArrays, 2, 0, "Rely on strict definition of flexible arrays")
COMPATIBLE_VALUE_LANGOPT(MaxTokens, 32, 0, "Max number of tokens per TU or 0")
Index: clang/include/clang/AST/Expr.h
===================================================================
--- clang/include/clang/AST/Expr.h
+++ clang/include/clang/AST/Expr.h
@@ -443,6 +443,16 @@
return (OK == OK_Ordinary || OK == OK_BitField);
}
+ /// True when this expression refers to a flexible array member in a
+ /// struct. \c StrictFlexArraysLevel controls which array bounds are
+ /// acceptable for such arrays:
+ ///
+ /// - 0 => any array bound,
+ /// - 1 => [0], [1], [ ]
+ /// - 2 => [0], [ ]
+ /// - 3 => [ ]
+ bool isFlexibleArrayMember(ASTContext &Ctx, int StrictFlexArraysLevel) const;
+
/// setValueKind - Set the value kind produced by this expression.
void setValueKind(ExprValueKind Cat) { ExprBits.ValueKind = Cat; }
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -68,6 +68,11 @@
Randomizing structure layout is a C-only feature.
+- Clang now supports the ``-fstrict-flex-arrays=<arg>`` option to control which
+ array bounds lead to flexible array members. The option yields more accurate
+ ``__builtin_object_size`` and ``__builtin_dynamic_object_size`` results in
+ most cases but may be overly conservative for some legacy code.
+
- Experimental support for HLSL has been added. The implementation is
incomplete and highly experimental. For more information about the ongoing
work to support HLSL see the `documentation
Index: clang/docs/ClangCommandLineReference.rst
===================================================================
--- clang/docs/ClangCommandLineReference.rst
+++ clang/docs/ClangCommandLineReference.rst
@@ -2639,6 +2639,12 @@
.. option:: -fuse-init-array, -fno-use-init-array
+.. option:: -fstrict-flex-arrays=<arg>, -fno-strict-flex-arrays
+
+Control which arrays are considered as flexible arrays members. <arg>
+can be 1 (array of size 0, 1 and undefined are considered), 2 (array of size 0
+and undefined are considered) or 3 (only array of undefined size are considered).
+
.. option:: -fuse-ld=<arg>
.. option:: -fuse-line-directives, -fno-use-line-directives
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