serge-sans-paille updated this revision to Diff 443185.
serge-sans-paille marked 4 inline comments as done.
serge-sans-paille added a comment.
Take reviews into account, basically spreading a lot of FIXME across the
codebase :'(
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D126864/new/
https://reviews.llvm.org/D126864
Files:
clang/docs/ClangCommandLineReference.rst
clang/docs/ReleaseNotes.rst
clang/include/clang/Basic/LangOptions.def
clang/include/clang/Driver/Options.td
clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
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-fam.c
clang/test/CodeGen/bounds-checking-fam.cpp
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
clang/test/SemaCXX/array-bounds.cpp
Index: clang/test/SemaCXX/array-bounds.cpp
===================================================================
--- clang/test/SemaCXX/array-bounds.cpp
+++ clang/test/SemaCXX/array-bounds.cpp
@@ -208,12 +208,15 @@
namespace metaprogramming {
#define ONE 1
- struct foo { char c[ONE]; }; // expected-note {{declared here}}
+struct foo {
+ char c[ONE]; // expected-note {{array 'c' declared here}}
+};
+
template <int N> struct bar { char c[N]; }; // expected-note {{declared here}}
char test(foo *F, bar<1> *B) {
return F->c[3] + // expected-warning {{array index 3 is past the end of the array (which contains 1 element)}}
- B->c[3]; // expected-warning {{array index 3 is past the end of the array (which contains 1 element)}}
+ B->c[3]; // expected-warning {{array index 3 is past the end of the array (which contains 1 element)}}
}
}
Index: clang/test/SemaCXX/array-bounds-strict-flex-arrays.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/array-bounds-strict-flex-arrays.cpp
@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -verify -fstrict-flex-arrays=2 %s
+
+// We cannot know for sure the size of a flexible array.
+struct t {
+ int f;
+ int a[];
+};
+void test(t *s2) {
+ s2->a[2] = 0; // no-warning
+}
+
+// Under -fstrict-flex-arrays `a` is not a flexible array.
+struct t1 {
+ int f;
+ int a[1]; // expected-note {{array 'a' declared here}}
+};
+void test1(t1 *s2) {
+ s2->a[2] = 0; // expected-warning {{array index 2 is past the end of the array (which contains 1 element)}}
+}
+
+// Under -fstrict-flex-arrays `a` is a flexible array.
+struct t2 {
+ int f;
+ int a[0];
+};
+void test1(t2 *s2) {
+ s2->a[2] = 0; // no-warning
+}
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 +1,6 @@
-// RUN: %clang_cc1 -verify -Warray-bounds-pointer-arithmetic %s
+// RUN: %clang_cc1 -verify=expected -Warray-bounds-pointer-arithmetic %s
+// RUN: %clang_cc1 -verify=expected -Warray-bounds-pointer-arithmetic %s -fstrict-flex-arrays=0
+// RUN: %clang_cc1 -verify=expected,strict -Warray-bounds-pointer-arithmetic %s -fstrict-flex-arrays=2
// Test case from PR10615
struct ext2_super_block{
@@ -14,7 +16,9 @@
}
// Test case reduced from PR11594
-struct S { int n; };
+struct S {
+ int n;
+};
void pr11594(struct S *s) {
int a[10];
int *p = a - s->n;
@@ -26,26 +30,28 @@
struct RDar11387038 {};
typedef struct RDar11387038 RDar11387038Array[1];
struct RDar11387038_Table {
- RDar11387038Array z;
+ RDar11387038Array z; // strict-note {{array 'z' declared here}}
};
-typedef struct RDar11387038_Table * TPtr;
+typedef struct RDar11387038_Table *TPtr;
typedef TPtr *TabHandle;
-struct RDar11387038_B { TabHandle x; };
+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];
+ struct RDar11387038 *y = &(*pRDar11387038_B->x)->z[4]; // strict-warning {{array index 4 is past the end of the array (which contains 1 element)}}
}
-void pr51682 (void) {
- int arr [1];
+void pr51682(void) {
+ int arr[1];
switch (0) {
- case 0:
- break;
- case 1:
- asm goto (""::"r"(arr[42] >> 1)::failed); // no-warning
- break;
+ case 0:
+ break;
+ case 1:
+ asm goto("" ::"r"(arr[42] >> 1)::failed);
+ 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 +1,98 @@
+// 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 %
+ 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 %
+ 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
+ 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
+ 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
+ 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
+ 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
+ return OBJECT_SIZE_BUILTIN(f->c, 1);
+}
Index: clang/test/CodeGen/bounds-checking-fam.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGen/bounds-checking-fam.cpp
@@ -0,0 +1,18 @@
+// 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
+//
+// Disable checks on FAM even though the class doesn't have standard layout.
+
+struct C {
+ int head;
+};
+
+struct S : C {
+ int tail[1];
+};
+
+// CHECK-LABEL: define {{.*}} @_Z8test_oneP1Si(
+int test_one(S *p, int i) {
+ // CHECK-STRICT-0-NOT: @__ubsan
+ return p->tail[i] + (p->tail)[i];
+}
Index: clang/test/CodeGen/bounds-checking-fam.c
===================================================================
--- clang/test/CodeGen/bounds-checking-fam.c
+++ clang/test/CodeGen/bounds-checking-fam.c
@@ -1,11 +1,14 @@
// 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 -x c++ %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-0,CXX,CXX-STRICT-0
-
-/// 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/84301
-/// Suppress such errors by default.
+// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fstrict-flex-arrays=0 -fsanitize=array-bounds %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-0
+// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fstrict-flex-arrays=0 -fsanitize=array-bounds -x c++ %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-0,CXX,CXX-STRICT-0
+// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fstrict-flex-arrays=1 -fsanitize=array-bounds %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-1
+// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fstrict-flex-arrays=1 -fsanitize=array-bounds -x c++ %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-1,CXX
+// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fstrict-flex-arrays=2 -fsanitize=array-bounds %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-2
+// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fstrict-flex-arrays=2 -fsanitize=array-bounds -x c++ %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-2,CXX
+// Before flexible array member was added to C99, many projects use a
+// one-element array as the last member 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];
};
@@ -19,18 +22,24 @@
// 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
@@ -794,7 +794,11 @@
if (Size.isZero())
return true;
+ if (getContext().getLangOpts().StrictFlexArrays >= 2)
+ return false;
+
const AnalyzerOptions &Opts = SVB.getAnalyzerOptions();
+ // FIXME: this option is probably redundant with -fstrict-flex-arrays=1.
if (Opts.ShouldConsiderSingleElementArraysAsFlexibleArrayMembers &&
Size.isOne())
return true;
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -15787,11 +15787,26 @@
/// 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 NamedDecl *ND,
+ unsigned StrictFlexArraysLevel) {
+ if (!ND)
+ return false;
+
+ if (StrictFlexArraysLevel >= 2 && Size != 0)
+ return false;
+
+ if (StrictFlexArraysLevel == 1 && Size.ule(1))
+ return false;
+
+ // FIXME: While the default -fstrict-flex-arrays=0 permits Size>1 trailing
+ // arrays to be treated as flexible-array-members, we still emit diagnostics
+ // as if they are not. Pending further discussion...
+ if (StrictFlexArraysLevel == 0 && Size != 1)
+ return false;
const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
- if (!FD) return false;
+ if (!FD)
+ return false;
// Don't consider sizes resulting from macro expansions or template argument
// substitution to form C89 tail-padded arrays.
@@ -15814,10 +15829,13 @@
}
const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
- if (!RD) return false;
- if (RD->isUnion()) return false;
+ if (!RD)
+ return false;
+ if (RD->isUnion())
+ return false;
if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
- if (!CRD->isStandardLayout()) return false;
+ if (!CRD->isStandardLayout())
+ return false;
}
// See if this is the last field decl in the record.
@@ -15945,9 +15963,14 @@
// example). In this case we have no information about whether the array
// access exceeds the array bounds. However we can still diagnose an array
// access which precedes the array bounds.
+ //
+ // FIXME: this check should be redundant with the IsUnboundedArray check
+ // above.
if (BaseType->isIncompleteType())
return;
+ // FIXME: this check should belong to the IsTailPaddedMemberArray call
+ // below.
llvm::APInt size = ArrayTy->getSize();
if (!size.isStrictlyPositive())
return;
@@ -15980,10 +16003,9 @@
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 Member emulation.
+ const unsigned StrictFlexArraysLevel = getLangOpts().StrictFlexArrays;
+ if (IsTailPaddedMemberArray(*this, size, ND, StrictFlexArraysLevel))
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
@@ -6232,6 +6232,8 @@
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
@@ -877,7 +877,8 @@
/// 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) {
+static bool isFlexibleArrayMemberExpr(const Expr *E,
+ unsigned StrictFlexArraysLevel) {
// 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
@@ -886,6 +887,11 @@
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 (StrictFlexArraysLevel >= 2 && CAT->getSize().ugt(0))
+ return false;
+ // FIXME: While the default -fstrict-flex-arrays=0 permits Size>1 trailing
+ // arrays to be treated as flexible-array-members, we still emit ubsan
+ // checks as if they are not.
if (CAT->getSize().ugt(1))
return false;
} else if (!isa<IncompleteArrayType>(AT))
@@ -900,8 +906,10 @@
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.
+ // Under StrictFlexArraysLevel, obey c99+ that disallows FAM in union, see
+ // C11 6.7.2.1 §18
if (FD->getParent()->isUnion())
- return true;
+ return StrictFlexArraysLevel < 2;
RecordDecl::field_iterator FI(
DeclContext::decl_iterator(const_cast<FieldDecl *>(FD)));
return ++FI == FD->getParent()->field_end();
@@ -954,8 +962,10 @@
/// 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,
+ unsigned 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 +976,7 @@
if (const auto *CE = dyn_cast<CastExpr>(Base)) {
if (CE->getCastKind() == CK_ArrayToPointerDecay &&
- !isFlexibleArrayMemberExpr(CE->getSubExpr())) {
+ !isFlexibleArrayMemberExpr(CE->getSubExpr(), StrictFlexArraysLevel)) {
IndexedType = CE->getSubExpr()->getType();
const ArrayType *AT = IndexedType->castAsArrayTypeUnsafe();
if (const auto *CAT = dyn_cast<ConstantArrayType>(AT))
@@ -993,8 +1003,11 @@
"should not be called unless adding bounds checks");
SanitizerScope SanScope(this);
+ const unsigned StrictFlexArraysLevel = getLangOpts().StrictFlexArrays;
+
QualType IndexedType;
- llvm::Value *Bound = getArrayIndexingBound(*this, Base, IndexedType);
+ llvm::Value *Bound =
+ getArrayIndexingBound(*this, Base, IndexedType, StrictFlexArraysLevel);
if (!Bound)
return;
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -11592,9 +11592,15 @@
// 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 ||
+ (Designator.getMostDerivedArraySize() == 1 &&
+ StrictFlexArraysLevel < 2) ||
+ StrictFlexArraysLevel == 0) &&
isDesignatorAtObjectEnd(Ctx, LVal);
}
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">,
+ 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/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -68,6 +68,10 @@
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
@@ -2643,6 +2643,12 @@
.. 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) or 2 (array of size 0
+and undefined are considered).
+
.. option:: -fuse-ld=<arg>
.. option:: -fuse-line-directives, -fno-use-line-directives
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