yihanaa updated this revision to Diff 456646.
yihanaa added a comment.
Use custom seam checking on __builtin_assume_aligned.
C++ not allow implicit cast from volatile void * to const void *, but C allowed
and only emit a warning. This is a general case, volatile in
__builtin_assume_aligned just use to ignore generate 'call void
@__ubsan_handle_alignment_assumption' in CodeGen. So, I use
GatherArgumentsForCall to handle the common case(e.g. emit diag message) except
1st arg, we ignore the implicit cast from user-written-type to 'const void *'
on the 1st arg, because CodeGen need user-written-type to generate correct
TypeDescriptor (this class in compiler-rt/UBSan), then, clang will emit cast
instruction which cast type from user-written-type to VoidPtr in CodeGen.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D131979/new/
https://reviews.llvm.org/D131979
Files:
clang/include/clang/Basic/Builtins.def
clang/lib/CodeGen/CGBuiltin.cpp
clang/lib/CodeGen/CodeGenFunction.cpp
clang/lib/Sema/SemaChecking.cpp
clang/test/CodeGen/catch-alignment-assumption-array.c
clang/test/CodeGen/catch-alignment-assumption-ignorelist.c
Index: clang/test/CodeGen/catch-alignment-assumption-ignorelist.c
===================================================================
--- clang/test/CodeGen/catch-alignment-assumption-ignorelist.c
+++ clang/test/CodeGen/catch-alignment-assumption-ignorelist.c
@@ -26,3 +26,9 @@
void *ignore_volatiles(volatile void * x) {
return __builtin_assume_aligned(x, 1);
}
+
+// CHECK-LABEL: ignore_array_volatiles
+void *ignore_array_volatiles() {
+ volatile int arr[] = {1};
+ return __builtin_assume_aligned(arr, 4);
+}
Index: clang/test/CodeGen/catch-alignment-assumption-array.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/catch-alignment-assumption-array.c
@@ -0,0 +1,32 @@
+// RUN: %clang_cc1 -no-opaque-pointers -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s
+// RUN: %clang_cc1 -no-opaque-pointers -fsanitize=alignment -fno-sanitize-recover=alignment -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s -implicit-check-not="call void @__ubsan_handle_alignment_assumption" --check-prefixes=CHECK,CHECK-SANITIZE,CHECK-SANITIZE-ANYRECOVER,CHECK-SANITIZE-NORECOVER,CHECK-SANITIZE-UNREACHABLE
+// RUN: %clang_cc1 -no-opaque-pointers -fsanitize=alignment -fsanitize-recover=alignment -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s -implicit-check-not="call void @__ubsan_handle_alignment_assumption" --check-prefixes=CHECK,CHECK-SANITIZE,CHECK-SANITIZE-ANYRECOVER,CHECK-SANITIZE-RECOVER
+// RUN: %clang_cc1 -no-opaque-pointers -fsanitize=alignment -fsanitize-trap=alignment -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s -implicit-check-not="call void @__ubsan_handle_alignment_assumption" --check-prefixes=CHECK,CHECK-SANITIZE,CHECK-SANITIZE-TRAP,CHECK-SANITIZE-UNREACHABLE
+
+// CHECK-SANITIZE-ANYRECOVER: @[[CHAR:.*]] = {{.*}} c"'char *'\00" }
+// CHECK-SANITIZE-ANYRECOVER: @[[ALIGNMENT_ASSUMPTION:.*]] = {{.*}}, i32 31, i32 35 }, {{.*}}* @[[CHAR]] }
+
+void *caller(void) {
+ char str[] = "";
+ // CHECK: define{{.*}}
+ // CHECK-NEXT: entry:
+ // CHECK-NEXT: %[[STR:.*]] = alloca [1 x i8], align 1
+ // CHECK-NEXT: %[[BITCAST:.*]] = bitcast [1 x i8]* %[[STR]] to i8*
+ // CHECK-NEXT: call void @llvm.memset.p0i8.i64(i8* align 1 %[[BITCAST]], i8 0, i64 1, i1 false)
+ // CHECK-NEXT: %[[ARRAYDECAY:.*]] = getelementptr inbounds [1 x i8], [1 x i8]* %[[STR]], i64 0, i64 0
+ // CHECK-SANITIZE-NEXT: %[[PTRINT:.*]] = ptrtoint i8* %[[ARRAYDECAY]] to i64
+ // CHECK-SANITIZE-NEXT: %[[MASKEDPTR:.*]] = and i64 %[[PTRINT]], 0
+ // CHECK-SANITIZE-NEXT: %[[MASKCOND:.*]] = icmp eq i64 %[[MASKEDPTR]], 0
+ // CHECK-SANITIZE-NEXT: %[[PTRINT_DUP:.*]] = ptrtoint i8* %[[ARRAYDECAY]] to i64, !nosanitize
+ // CHECK-SANITIZE-NEXT: br i1 %[[MASKCOND]], label %[[CONT:.*]], label %[[HANDLER_ALIGNMENT_ASSUMPTION:[^,]+]],{{.*}} !nosanitize
+ // CHECK-SANITIZE: [[HANDLER_ALIGNMENT_ASSUMPTION]]:
+ // CHECK-SANITIZE-NORECOVER-NEXT: call void @__ubsan_handle_alignment_assumption_abort(i8* bitcast ({ {{{.*}}}, {{{.*}}}, {{{.*}}}* }* @[[ALIGNMENT_ASSUMPTION]] to i8*), i64 %[[PTRINT_DUP]], i64 1, i64 0){{.*}}, !nosanitize
+ // CHECK-SANITIZE-RECOVER-NEXT: call void @__ubsan_handle_alignment_assumption(i8* bitcast ({ {{{.*}}}, {{{.*}}}, {{{.*}}}* }* @[[ALIGNMENT_ASSUMPTION]] to i8*), i64 %[[PTRINT_DUP]], i64 1, i64 0){{.*}}, !nosanitize
+ // CHECK-SANITIZE-TRAP-NEXT: call void @llvm.ubsantrap(i8 23){{.*}}, !nosanitize
+ // CHECK-SANITIZE-UNREACHABLE-NEXT: unreachable, !nosanitize
+ // CHECK-SANITIZE: [[CONT]]:
+ // CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(i8* %[[ARRAYDECAY]], i64 1) ]
+ // CHECK-NEXT: ret i8* %[[ARRAYDECAY]]
+ // CHECK-NEXT: }
+ return __builtin_assume_aligned(str, 1);
+}
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -7644,38 +7644,82 @@
/// Handle __builtin_assume_aligned. This is declared
/// as (const void*, size_t, ...) and can take one optional constant int arg.
bool Sema::SemaBuiltinAssumeAligned(CallExpr *TheCall) {
+ Expr *Callee = TheCall->getCallee();
+ DeclRefExpr *DRE = cast<DeclRefExpr>(Callee->IgnoreCasts());
+ FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
+ const auto *Proto = FDecl->getType()->getAs<FunctionProtoType>();
+ ArrayRef<Expr *> Args(TheCall->getArgs(), TheCall->getNumArgs());
unsigned NumArgs = TheCall->getNumArgs();
+ // Ensure that we have at least one argument to do type inference from.
+ if (NumArgs < 1) {
+ return Diag(TheCall->getEndLoc(),
+ diag::err_typecheck_call_too_few_args_at_least)
+ << 0 << 2 << TheCall->getNumArgs() << Callee->getSourceRange();
+ }
+
if (NumArgs > 3)
return Diag(TheCall->getEndLoc(),
diag::err_typecheck_call_too_many_args_at_most)
<< 0 /*function call*/ << 3 << NumArgs << TheCall->getSourceRange();
+ SmallVector<Expr *, 8> AllArgs;
+ VariadicCallType CallType = getVariadicCallType(FDecl, Proto, Callee);
+
+ if (GatherArgumentsForCall(TheCall->getBeginLoc(), FDecl, Proto, 0, Args,
+ AllArgs, CallType))
+ return true;
+
+ Expr *FirstArg = Args[0];
+ if (FirstArg->getType()->isFunctionType() ||
+ FirstArg->getType()->isArrayType()) {
+ ExprResult Result = DefaultFunctionArrayConversion(FirstArg);
+ if (Result.isInvalid())
+ return true;
+ FirstArg = Result.get();
+ }
+
+ ExprResult FirstArgResult = DefaultLvalueConversion(FirstArg);
+ if (FirstArgResult.isInvalid())
+ return true;
+
+ // Ignore the implicit cast from user-written-type to 'const void *' on the
+ // 1st arg, because CodeGen need user-written-type to generate correct
+ // TypeDescriptor (this class in compiler-rt/UBSan), then, clang will emit
+ // cast instruction which cast type from user-written-type to VoidPtr in
+ // CodeGen.
+ AllArgs[0] = FirstArgResult.get();
+ unsigned TotalNumArgs = AllArgs.size();
+ for (unsigned i = 0; i < TotalNumArgs; ++i)
+ TheCall->setArg(i, AllArgs[i]);
+ TheCall->computeDependence();
+
// The alignment must be a constant integer.
- Expr *Arg = TheCall->getArg(1);
+ Expr *SecondArg = TheCall->getArg(1);
// We can't check the value of a dependent argument.
- if (!Arg->isTypeDependent() && !Arg->isValueDependent()) {
+ if (!SecondArg->isTypeDependent() && !SecondArg->isValueDependent()) {
llvm::APSInt Result;
if (SemaBuiltinConstantArg(TheCall, 1, Result))
return true;
if (!Result.isPowerOf2())
return Diag(TheCall->getBeginLoc(), diag::err_alignment_not_power_of_two)
- << Arg->getSourceRange();
+ << SecondArg->getSourceRange();
if (Result > Sema::MaximumAlignment)
Diag(TheCall->getBeginLoc(), diag::warn_assume_aligned_too_great)
- << Arg->getSourceRange() << Sema::MaximumAlignment;
+ << SecondArg->getSourceRange() << Sema::MaximumAlignment;
}
if (NumArgs > 2) {
- ExprResult Arg(TheCall->getArg(2));
- InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
- Context.getSizeType(), false);
- Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
- if (Arg.isInvalid()) return true;
- TheCall->setArg(2, Arg.get());
+ ExprResult ThirdArg(TheCall->getArg(2));
+ InitializedEntity Entity = InitializedEntity::InitializeParameter(
+ Context, Context.getSizeType(), false);
+ ThirdArg = PerformCopyInitialization(Entity, SourceLocation(), ThirdArg);
+ if (ThirdArg.isInvalid())
+ return true;
+ TheCall->setArg(2, ThirdArg.get());
}
return false;
Index: clang/lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.cpp
+++ clang/lib/CodeGen/CodeGenFunction.cpp
@@ -2443,8 +2443,6 @@
SourceLocation AssumptionLoc,
llvm::Value *Alignment,
llvm::Value *OffsetValue) {
- if (auto *CE = dyn_cast<CastExpr>(E))
- E = CE->getSubExprAsWritten();
QualType Ty = E->getType();
SourceLocation Loc = E->getExprLoc();
@@ -2718,6 +2716,7 @@
assert(&(Builder.GetInsertBlock()->back()) == Assumption &&
"Assumption should be the last instruction of the basic block, "
"since the basic block is still being generated.");
+ assert(Ty->isPointerType() && "The first arg must be pointer type");
if (!SanOpts.has(SanitizerKind::Alignment))
return;
Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -2781,6 +2781,8 @@
case Builtin::BI__builtin_assume_aligned: {
const Expr *Ptr = E->getArg(0);
Value *PtrValue = EmitScalarExpr(Ptr);
+ if (PtrValue->getType() != VoidPtrTy)
+ PtrValue = EmitCastToVoidPtr(PtrValue);
Value *OffsetValue =
(E->getNumArgs() > 2) ? EmitScalarExpr(E->getArg(2)) : nullptr;
Index: clang/include/clang/Basic/Builtins.def
===================================================================
--- clang/include/clang/Basic/Builtins.def
+++ clang/include/clang/Basic/Builtins.def
@@ -546,7 +546,7 @@
BUILTIN(__builtin_va_end, "vA", "n")
BUILTIN(__builtin_va_copy, "vAA", "n")
BUILTIN(__builtin_stdarg_start, "vA.", "nt")
-BUILTIN(__builtin_assume_aligned, "v*vC*z.", "nc")
+BUILTIN(__builtin_assume_aligned, "v*vC*z.", "nct")
BUILTIN(__builtin_bcmp, "ivC*vC*z", "Fn")
BUILTIN(__builtin_bcopy, "vv*v*z", "n")
BUILTIN(__builtin_bzero, "vv*z", "nF")
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