This revision was automatically updated to reflect the committed changes.
Closed by commit rG072cde03aaa1: [Clang][BPF] implement __builtin_btf_type_id()
builtin function (authored by yonghong-song).
Changed prior to commit:
https://reviews.llvm.org/D74668?vs=261976&id=264273#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D74668/new/
https://reviews.llvm.org/D74668
Files:
clang/include/clang/Basic/BuiltinsBPF.def
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/CodeGen/CGBuiltin.cpp
clang/lib/Sema/SemaChecking.cpp
clang/test/CodeGen/builtin-bpf-btf-type-id.c
clang/test/Sema/builtin-bpf-btf-type-id.c
llvm/include/llvm/IR/IntrinsicsBPF.td
Index: llvm/include/llvm/IR/IntrinsicsBPF.td
===================================================================
--- llvm/include/llvm/IR/IntrinsicsBPF.td
+++ llvm/include/llvm/IR/IntrinsicsBPF.td
@@ -23,4 +23,7 @@
def int_bpf_preserve_field_info : GCCBuiltin<"__builtin_bpf_preserve_field_info">,
Intrinsic<[llvm_i32_ty], [llvm_anyptr_ty, llvm_i64_ty],
[IntrNoMem, ImmArg<1>]>;
+ def int_bpf_btf_type_id : GCCBuiltin<"__builtin_bpf_btf_type_id">,
+ Intrinsic<[llvm_i32_ty], [llvm_any_ty, llvm_any_ty, llvm_i64_ty],
+ [IntrNoMem]>;
}
Index: clang/test/Sema/builtin-bpf-btf-type-id.c
===================================================================
--- /dev/null
+++ clang/test/Sema/builtin-bpf-btf-type-id.c
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -x c -triple bpf-pc-linux-gnu -dwarf-version=4 -fsyntax-only -verify %s
+
+struct {
+ char f1[100];
+ int f2;
+} tmp = {};
+
+unsigned invalid1() { return __builtin_btf_type_id(1, tmp); } // expected-error {{__builtin_btf_type_id argument 2 not a constant}}
+unsigned invalid2() { return __builtin_btf_type_id(1, 1, 1); } // expected-error {{too many arguments to function call, expected 2, have 3}}
+
+int valid1() { return __builtin_btf_type_id(tmp, 0); }
+int valid2() { return __builtin_btf_type_id(&tmp, 1); }
+int valid3() { return __builtin_btf_type_id(tmp.f1[4], 10); }
Index: clang/test/CodeGen/builtin-bpf-btf-type-id.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/builtin-bpf-btf-type-id.c
@@ -0,0 +1,13 @@
+// REQUIRES: bpf-registered-target
+// RUN: %clang -target bpf -emit-llvm -S -g %s -o - | FileCheck %s
+
+unsigned test1(int a) { return __builtin_btf_type_id(a, 0); }
+unsigned test2(int a) { return __builtin_btf_type_id(&a, 0); }
+
+// CHECK: define dso_local i32 @test1
+// CHECK: call i32 @llvm.bpf.btf.type.id.p0i32.i32(i32* %{{[0-9a-z.]+}}, i32 1, i64 0), !dbg !{{[0-9]+}}, !llvm.preserve.access.index ![[INT:[0-9]+]]
+// CHECK: define dso_local i32 @test2
+// CHECK: call i32 @llvm.bpf.btf.type.id.p0i32.i32(i32* %{{[0-9a-z.]+}}, i32 0, i64 0), !dbg !{{[0-9]+}}, !llvm.preserve.access.index ![[INT_POINTER:[0-9]+]]
+//
+// CHECK: ![[INT]] = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed
+// CHECK: ![[INT_POINTER]] = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: ![[INT]], size: 64
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -2487,17 +2487,33 @@
bool Sema::CheckBPFBuiltinFunctionCall(unsigned BuiltinID,
CallExpr *TheCall) {
- assert(BuiltinID == BPF::BI__builtin_preserve_field_info &&
+ assert((BuiltinID == BPF::BI__builtin_preserve_field_info ||
+ BuiltinID == BPF::BI__builtin_btf_type_id) &&
"unexpected ARM builtin");
if (checkArgCount(*this, TheCall, 2))
return true;
+ Expr *Arg;
+ if (BuiltinID == BPF::BI__builtin_btf_type_id) {
+ // The second argument needs to be a constant int
+ llvm::APSInt Value;
+ Arg = TheCall->getArg(1);
+ if (!Arg->isIntegerConstantExpr(Value, Context)) {
+ Diag(Arg->getBeginLoc(), diag::err_btf_type_id_not_const)
+ << 2 << Arg->getSourceRange();
+ return true;
+ }
+
+ TheCall->setType(Context.UnsignedIntTy);
+ return false;
+ }
+
// The first argument needs to be a record field access.
// If it is an array element access, we delay decision
// to BPF backend to check whether the access is a
// field access or not.
- Expr *Arg = TheCall->getArg(0);
+ Arg = TheCall->getArg(0);
if (Arg->getType()->getAsPlaceholderType() ||
(Arg->IgnoreParens()->getObjectKind() != OK_BitField &&
!dyn_cast<MemberExpr>(Arg->IgnoreParens()) &&
@@ -2508,8 +2524,9 @@
}
// The second argument needs to be a constant int
+ Arg = TheCall->getArg(1);
llvm::APSInt Value;
- if (!TheCall->getArg(1)->isIntegerConstantExpr(Value, Context)) {
+ if (!Arg->isIntegerConstantExpr(Value, Context)) {
Diag(Arg->getBeginLoc(), diag::err_preserve_field_info_not_const)
<< 2 << Arg->getSourceRange();
return true;
Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -10633,33 +10633,103 @@
Value *CodeGenFunction::EmitBPFBuiltinExpr(unsigned BuiltinID,
const CallExpr *E) {
- assert(BuiltinID == BPF::BI__builtin_preserve_field_info &&
- "unexpected ARM builtin");
+ assert((BuiltinID == BPF::BI__builtin_preserve_field_info ||
+ BuiltinID == BPF::BI__builtin_btf_type_id) &&
+ "unexpected BPF builtin");
- const Expr *Arg = E->getArg(0);
- bool IsBitField = Arg->IgnoreParens()->getObjectKind() == OK_BitField;
+ switch (BuiltinID) {
+ default:
+ llvm_unreachable("Unexpected BPF builtin");
+ case BPF::BI__builtin_preserve_field_info: {
+ const Expr *Arg = E->getArg(0);
+ bool IsBitField = Arg->IgnoreParens()->getObjectKind() == OK_BitField;
- if (!getDebugInfo()) {
- CGM.Error(E->getExprLoc(), "using builtin_preserve_field_info() without -g");
- return IsBitField ? EmitLValue(Arg).getBitFieldPointer()
- : EmitLValue(Arg).getPointer(*this);
- }
+ if (!getDebugInfo()) {
+ CGM.Error(E->getExprLoc(),
+ "using __builtin_preserve_field_info() without -g");
+ return IsBitField ? EmitLValue(Arg).getBitFieldPointer()
+ : EmitLValue(Arg).getPointer(*this);
+ }
+
+ // Enable underlying preserve_*_access_index() generation.
+ bool OldIsInPreservedAIRegion = IsInPreservedAIRegion;
+ IsInPreservedAIRegion = true;
+ Value *FieldAddr = IsBitField ? EmitLValue(Arg).getBitFieldPointer()
+ : EmitLValue(Arg).getPointer(*this);
+ IsInPreservedAIRegion = OldIsInPreservedAIRegion;
+
+ ConstantInt *C = cast<ConstantInt>(EmitScalarExpr(E->getArg(1)));
+ Value *InfoKind = ConstantInt::get(Int64Ty, C->getSExtValue());
+
+ // Built the IR for the preserve_field_info intrinsic.
+ llvm::Function *FnGetFieldInfo = llvm::Intrinsic::getDeclaration(
+ &CGM.getModule(), llvm::Intrinsic::bpf_preserve_field_info,
+ {FieldAddr->getType()});
+ return Builder.CreateCall(FnGetFieldInfo, {FieldAddr, InfoKind});
+ }
+ case BPF::BI__builtin_btf_type_id: {
+ Value *FieldVal = nullptr;
+
+ // The LValue cannot be converted Value in order to be used as the function
+ // parameter. If it is a structure, it is the "alloca" result of the LValue
+ // (a pointer) is used in the parameter. If it is a simple type,
+ // the value will be loaded from its corresponding "alloca" and used as
+ // the parameter. In our case, let us just get a pointer of the LValue
+ // since we do not really use the parameter. The purpose of parameter
+ // is to prevent the generated IR llvm.bpf.btf.type.id intrinsic call,
+ // which carries metadata, from being changed.
+ bool IsLValue = E->getArg(0)->isLValue();
+ if (IsLValue)
+ FieldVal = EmitLValue(E->getArg(0)).getPointer(*this);
+ else
+ FieldVal = EmitScalarExpr(E->getArg(0));
- // Enable underlying preserve_*_access_index() generation.
- bool OldIsInPreservedAIRegion = IsInPreservedAIRegion;
- IsInPreservedAIRegion = true;
- Value *FieldAddr = IsBitField ? EmitLValue(Arg).getBitFieldPointer()
- : EmitLValue(Arg).getPointer(*this);
- IsInPreservedAIRegion = OldIsInPreservedAIRegion;
+ if (!getDebugInfo()) {
+ CGM.Error(E->getExprLoc(), "using __builtin_btf_type_id() without -g");
+ return nullptr;
+ }
- ConstantInt *C = cast<ConstantInt>(EmitScalarExpr(E->getArg(1)));
- Value *InfoKind = ConstantInt::get(Int64Ty, C->getSExtValue());
+ // Generate debuginfo type for the first argument.
+ llvm::DIType *DbgInfo =
+ getDebugInfo()->getOrCreateStandaloneType(E->getArg(0)->getType(),
+ E->getArg(0)->getExprLoc());
- // Built the IR for the preserve_field_info intrinsic.
- llvm::Function *FnGetFieldInfo = llvm::Intrinsic::getDeclaration(
- &CGM.getModule(), llvm::Intrinsic::bpf_preserve_field_info,
- {FieldAddr->getType()});
- return Builder.CreateCall(FnGetFieldInfo, {FieldAddr, InfoKind});
+ ConstantInt *Flag = cast<ConstantInt>(EmitScalarExpr(E->getArg(1)));
+ Value *FlagValue = ConstantInt::get(Int64Ty, Flag->getSExtValue());
+
+ // Built the IR for the btf_type_id intrinsic.
+ //
+ // In the above, we converted LValue argument to a pointer to LValue.
+ // For example, the following
+ // int v;
+ // C1: __builtin_btf_type_id(v, flag);
+ // will be converted to
+ // L1: llvm.bpf.btf.type.id(&v, flag)
+ // This makes it hard to differentiate from
+ // C2: __builtin_btf_type_id(&v, flag);
+ // to
+ // L2: llvm.bpf.btf.type.id(&v, flag)
+ //
+ // If both C1 and C2 are present in the code, the llvm may later
+ // on do CSE on L1 and L2, which will result in incorrect tagged types.
+ //
+ // The C1->L1 transformation only happens if the argument of
+ // __builtin_btf_type_id() is a LValue. So Let us put whether
+ // the argument is an LValue or not into generated IR. This should
+ // prevent potential CSE from causing debuginfo type loss.
+ //
+ // The generated IR intrinsics will hence look like
+ // L1: llvm.bpf.btf.type.id(&v, 1, flag) !di_type_for_{v};
+ // L2: llvm.bpf.btf.type.id(&v, 0, flag) !di_type_for_{&v};
+ Constant *CV = ConstantInt::get(IntTy, IsLValue);
+ llvm::Function *FnBtfTypeId = llvm::Intrinsic::getDeclaration(
+ &CGM.getModule(), llvm::Intrinsic::bpf_btf_type_id,
+ {FieldVal->getType(), CV->getType()});
+ CallInst *Fn = Builder.CreateCall(FnBtfTypeId, {FieldVal, CV, FlagValue});
+ Fn->setMetadata(LLVMContext::MD_preserve_access_index, DbgInfo);
+ return Fn;
+ }
+ }
}
llvm::Value *CodeGenFunction::
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10749,6 +10749,8 @@
"__builtin_preserve_field_info argument %0 not a field access">;
def err_preserve_field_info_not_const: Error<
"__builtin_preserve_field_info argument %0 not a constant">;
+def err_btf_type_id_not_const: Error<
+ "__builtin_btf_type_id argument %0 not a constant">;
def err_bit_cast_non_trivially_copyable : Error<
"__builtin_bit_cast %select{source|destination}0 type must be trivially copyable">;
Index: clang/include/clang/Basic/BuiltinsBPF.def
===================================================================
--- clang/include/clang/Basic/BuiltinsBPF.def
+++ clang/include/clang/Basic/BuiltinsBPF.def
@@ -20,5 +20,8 @@
// Get record field information.
TARGET_BUILTIN(__builtin_preserve_field_info, "Ui.", "t", "")
+// Get BTF type id.
+TARGET_BUILTIN(__builtin_btf_type_id, "Ui.", "t", "")
+
#undef BUILTIN
#undef TARGET_BUILTIN
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