erik.pilkington created this revision.
erik.pilkington added reviewers: rsmith, jfb, rjmccall.
Herald added subscribers: llvm-commits, kristina, arphaman, dexonsmith,
jkorous, hiraditya.
Herald added projects: clang, LLVM.
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0476r2.html
This adds a new (pseudo) builtin, `__builtin_bit_cast(T, v)`, which performs a
bit_cast from a value v to a type T. This expression can be evaluated at
compile time under specific circumstances. The compile time evaluation
currently doesn't support bit-fields, but I'm planning on fixing this in a
follow up (some of the logic for figuring this out is in CodeGen).
rdar://44987528
Thanks for taking a look!
Repository:
rC Clang
https://reviews.llvm.org/D62825
Files:
clang/include/clang-c/Index.h
clang/include/clang/AST/ExprCXX.h
clang/include/clang/AST/OperationKinds.def
clang/include/clang/AST/RecursiveASTVisitor.h
clang/include/clang/Basic/DiagnosticASTKinds.td
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/include/clang/Basic/Features.def
clang/include/clang/Basic/StmtNodes.td
clang/include/clang/Basic/TokenKinds.def
clang/include/clang/Parse/Parser.h
clang/include/clang/Sema/Sema.h
clang/lib/AST/Expr.cpp
clang/lib/AST/ExprClassification.cpp
clang/lib/AST/ExprConstant.cpp
clang/lib/AST/ItaniumMangle.cpp
clang/lib/AST/StmtPrinter.cpp
clang/lib/AST/StmtProfile.cpp
clang/lib/CodeGen/CGExpr.cpp
clang/lib/CodeGen/CGExprAgg.cpp
clang/lib/CodeGen/CGExprComplex.cpp
clang/lib/CodeGen/CGExprConstant.cpp
clang/lib/CodeGen/CGExprScalar.cpp
clang/lib/Edit/RewriteObjCFoundationAPI.cpp
clang/lib/Parse/ParseExpr.cpp
clang/lib/Parse/ParseExprCXX.cpp
clang/lib/Sema/SemaCast.cpp
clang/lib/Sema/SemaExceptionSpec.cpp
clang/lib/Sema/TreeTransform.h
clang/lib/Serialization/ASTReaderStmt.cpp
clang/lib/Serialization/ASTWriterStmt.cpp
clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
clang/test/CodeGenCXX/builtin-bit-cast.cpp
clang/test/SemaCXX/builtin-bit-cast.cpp
clang/test/SemaCXX/constexpr-builtin-bit-cast.cpp
clang/tools/libclang/CIndex.cpp
clang/tools/libclang/CXCursor.cpp
llvm/include/llvm/ADT/APInt.h
llvm/lib/ExecutionEngine/ExecutionEngine.cpp
llvm/lib/Support/APInt.cpp
Index: llvm/lib/Support/APInt.cpp
===================================================================
--- llvm/lib/Support/APInt.cpp
+++ llvm/lib/Support/APInt.cpp
@@ -2929,3 +2929,56 @@
LLVM_DEBUG(dbgs() << __func__ << ": solution (wrap): " << X << '\n');
return X;
}
+
+/// StoreIntToMemory - Fills the StoreBytes bytes of memory starting from Dst
+/// with the integer held in IntVal.
+void llvm::StoreIntToMemory(const APInt &IntVal, uint8_t *Dst,
+ unsigned StoreBytes) {
+ assert((IntVal.getBitWidth()+7)/8 >= StoreBytes && "Integer too small!");
+ const uint8_t *Src = (const uint8_t *)IntVal.getRawData();
+
+ if (sys::IsLittleEndianHost) {
+ // Little-endian host - the source is ordered from LSB to MSB. Order the
+ // destination from LSB to MSB: Do a straight copy.
+ memcpy(Dst, Src, StoreBytes);
+ } else {
+ // Big-endian host - the source is an array of 64 bit words ordered from
+ // LSW to MSW. Each word is ordered from MSB to LSB. Order the destination
+ // from MSB to LSB: Reverse the word order, but not the bytes in a word.
+ while (StoreBytes > sizeof(uint64_t)) {
+ StoreBytes -= sizeof(uint64_t);
+ // May not be aligned so use memcpy.
+ memcpy(Dst + StoreBytes, Src, sizeof(uint64_t));
+ Src += sizeof(uint64_t);
+ }
+
+ memcpy(Dst, Src + sizeof(uint64_t) - StoreBytes, StoreBytes);
+ }
+}
+
+/// LoadIntFromMemory - Loads the integer stored in the LoadBytes bytes starting
+/// from Src into IntVal, which is assumed to be wide enough and to hold zero.
+void llvm::LoadIntFromMemory(APInt &IntVal, uint8_t *Src, unsigned LoadBytes) {
+ assert((IntVal.getBitWidth()+7)/8 >= LoadBytes && "Integer too small!");
+ uint8_t *Dst = reinterpret_cast<uint8_t *>(
+ const_cast<uint64_t *>(IntVal.getRawData()));
+
+ if (sys::IsLittleEndianHost)
+ // Little-endian host - the destination must be ordered from LSB to MSB.
+ // The source is ordered from LSB to MSB: Do a straight copy.
+ memcpy(Dst, Src, LoadBytes);
+ else {
+ // Big-endian - the destination is an array of 64 bit words ordered from
+ // LSW to MSW. Each word must be ordered from MSB to LSB. The source is
+ // ordered from MSB to LSB: Reverse the word order, but not the bytes in
+ // a word.
+ while (LoadBytes > sizeof(uint64_t)) {
+ LoadBytes -= sizeof(uint64_t);
+ // May not be aligned so use memcpy.
+ memcpy(Dst, Src + LoadBytes, sizeof(uint64_t));
+ Dst += sizeof(uint64_t);
+ }
+
+ memcpy(Dst + sizeof(uint64_t) - LoadBytes, Src, LoadBytes);
+ }
+}
Index: llvm/lib/ExecutionEngine/ExecutionEngine.cpp
===================================================================
--- llvm/lib/ExecutionEngine/ExecutionEngine.cpp
+++ llvm/lib/ExecutionEngine/ExecutionEngine.cpp
@@ -1019,32 +1019,6 @@
return Result;
}
-/// StoreIntToMemory - Fills the StoreBytes bytes of memory starting from Dst
-/// with the integer held in IntVal.
-static void StoreIntToMemory(const APInt &IntVal, uint8_t *Dst,
- unsigned StoreBytes) {
- assert((IntVal.getBitWidth()+7)/8 >= StoreBytes && "Integer too small!");
- const uint8_t *Src = (const uint8_t *)IntVal.getRawData();
-
- if (sys::IsLittleEndianHost) {
- // Little-endian host - the source is ordered from LSB to MSB. Order the
- // destination from LSB to MSB: Do a straight copy.
- memcpy(Dst, Src, StoreBytes);
- } else {
- // Big-endian host - the source is an array of 64 bit words ordered from
- // LSW to MSW. Each word is ordered from MSB to LSB. Order the destination
- // from MSB to LSB: Reverse the word order, but not the bytes in a word.
- while (StoreBytes > sizeof(uint64_t)) {
- StoreBytes -= sizeof(uint64_t);
- // May not be aligned so use memcpy.
- memcpy(Dst + StoreBytes, Src, sizeof(uint64_t));
- Src += sizeof(uint64_t);
- }
-
- memcpy(Dst, Src + sizeof(uint64_t) - StoreBytes, StoreBytes);
- }
-}
-
void ExecutionEngine::StoreValueToMemory(const GenericValue &Val,
GenericValue *Ptr, Type *Ty) {
const unsigned StoreBytes = getDataLayout().getTypeStoreSize(Ty);
@@ -1092,33 +1066,6 @@
std::reverse((uint8_t*)Ptr, StoreBytes + (uint8_t*)Ptr);
}
-/// LoadIntFromMemory - Loads the integer stored in the LoadBytes bytes starting
-/// from Src into IntVal, which is assumed to be wide enough and to hold zero.
-static void LoadIntFromMemory(APInt &IntVal, uint8_t *Src, unsigned LoadBytes) {
- assert((IntVal.getBitWidth()+7)/8 >= LoadBytes && "Integer too small!");
- uint8_t *Dst = reinterpret_cast<uint8_t *>(
- const_cast<uint64_t *>(IntVal.getRawData()));
-
- if (sys::IsLittleEndianHost)
- // Little-endian host - the destination must be ordered from LSB to MSB.
- // The source is ordered from LSB to MSB: Do a straight copy.
- memcpy(Dst, Src, LoadBytes);
- else {
- // Big-endian - the destination is an array of 64 bit words ordered from
- // LSW to MSW. Each word must be ordered from MSB to LSB. The source is
- // ordered from MSB to LSB: Reverse the word order, but not the bytes in
- // a word.
- while (LoadBytes > sizeof(uint64_t)) {
- LoadBytes -= sizeof(uint64_t);
- // May not be aligned so use memcpy.
- memcpy(Dst, Src + LoadBytes, sizeof(uint64_t));
- Dst += sizeof(uint64_t);
- }
-
- memcpy(Dst + sizeof(uint64_t) - LoadBytes, Src, LoadBytes);
- }
-}
-
/// FIXME: document
///
void ExecutionEngine::LoadValueFromMemory(GenericValue &Result,
Index: llvm/include/llvm/ADT/APInt.h
===================================================================
--- llvm/include/llvm/ADT/APInt.h
+++ llvm/include/llvm/ADT/APInt.h
@@ -2212,6 +2212,15 @@
// See friend declaration above. This additional declaration is required in
// order to compile LLVM with IBM xlC compiler.
hash_code hash_value(const APInt &Arg);
-} // End of llvm namespace
+
+/// StoreIntToMemory - Fills the StoreBytes bytes of memory starting from Dst
+/// with the integer held in IntVal.
+void StoreIntToMemory(const APInt &IntVal, uint8_t *Dst, unsigned StoreBytes);
+
+/// LoadIntFromMemory - Loads the integer stored in the LoadBytes bytes starting
+/// from Src into IntVal, which is assumed to be wide enough and to hold zero.
+void LoadIntFromMemory(APInt &IntVal, uint8_t *Src, unsigned LoadBytes);
+
+} // namespace llvm
#endif
Index: clang/tools/libclang/CXCursor.cpp
===================================================================
--- clang/tools/libclang/CXCursor.cpp
+++ clang/tools/libclang/CXCursor.cpp
@@ -716,6 +716,8 @@
case Stmt::OMPTargetTeamsDistributeSimdDirectiveClass:
K = CXCursor_OMPTargetTeamsDistributeSimdDirective;
break;
+ case Stmt::BuiltinBitCastExprClass:
+ K = CXCursor_BuiltinBitCastExpr;
}
CXCursor C = { K, 0, { Parent, S, TU } };
Index: clang/tools/libclang/CIndex.cpp
===================================================================
--- clang/tools/libclang/CIndex.cpp
+++ clang/tools/libclang/CIndex.cpp
@@ -5190,6 +5190,8 @@
return cxstring::createRef("CallExpr");
case CXCursor_ObjCMessageExpr:
return cxstring::createRef("ObjCMessageExpr");
+ case CXCursor_BuiltinBitCastExpr:
+ return cxstring::createRef("BuiltinBitCastExpr");
case CXCursor_UnexposedStmt:
return cxstring::createRef("UnexposedStmt");
case CXCursor_DeclStmt:
Index: clang/test/SemaCXX/constexpr-builtin-bit-cast.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/constexpr-builtin-bit-cast.cpp
@@ -0,0 +1,212 @@
+// RUN: %clang_cc1 -verify -std=c++2a -fsyntax-only -triple x86_64-apple-macosx10.14.0 %s
+// RUN: %clang_cc1 -verify -std=c++2a -fsyntax-only -triple aarch64_be-linux-gnu %s
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+# define LITTLE_END 1
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+# define LITTLE_END 0
+#else
+# error "huh?"
+#endif
+
+template <class T, class V> struct is_same {
+ static constexpr bool value = false;
+};
+template <class T> struct is_same<T, T> {
+ static constexpr bool value = true;
+};
+
+static_assert(sizeof(int) == 4);
+static_assert(sizeof(long long) == 8);
+
+template <class To, class From>
+constexpr To bit_cast(const From &from) {
+ static_assert(sizeof(To) == sizeof(From));
+ static_assert(!is_same<To, From>::value);
+ return __builtin_bit_cast(To, from);
+}
+
+template <class Intermediate, class Init>
+constexpr int round_trip(const Init &init) {
+ return bit_cast<Init>(bit_cast<Intermediate>(init)) == init;
+}
+
+void test_int() {
+ static_assert(round_trip<unsigned>((int)-1));
+ static_assert(round_trip<unsigned>((int)0x12345678));
+ static_assert(round_trip<unsigned>((int)0x87654321));
+ static_assert(round_trip<unsigned>((int)0x0C05FEFE));
+}
+
+void test_array() {
+ constexpr unsigned char input[] = {0xCA, 0xFE, 0xBA, 0xBE};
+ constexpr unsigned expected = LITTLE_END ? 0xBEBAFECA : 0xCAFEBABE;
+ static_assert(bit_cast<unsigned>(input) == expected);
+}
+
+void test_record() {
+ struct int_splicer {
+ unsigned x;
+ unsigned y;
+
+ constexpr bool operator==(const int_splicer &other) const {
+ return other.x == x && other.y == y;
+ }
+ };
+
+ constexpr int_splicer splice{0x0C05FEFE, 0xCAFEBABE};
+
+ static_assert(bit_cast<unsigned long long>(splice) == LITTLE_END
+ ? 0xCAFEBABE0C05FEFE
+ : 0x0C05FEFECAFEBABE);
+
+ static_assert(bit_cast<int_splicer>(0xCAFEBABE0C05FEFE).x == LITTLE_END
+ ? 0x0C05FEFE
+ : 0xCAFEBABE);
+
+ static_assert(round_trip<unsigned long long>(splice));
+ static_assert(round_trip<long long>(splice));
+
+ struct base2 {
+ };
+
+ struct base3 {
+ unsigned z;
+ };
+
+ struct bases : int_splicer, base2, base3 {
+ unsigned doublez;
+ };
+
+ struct tuple4 {
+ unsigned x, y, z, doublez;
+
+ constexpr bool operator==(tuple4 const &other) const {
+ return x == other.x && y == other.y &&
+ z == other.z && doublez == other.doublez;
+ }
+ };
+ constexpr bases b = {{1, 2}, {}, {3}, 4};
+ constexpr tuple4 t4 = bit_cast<tuple4>(b);
+ static_assert(t4 == tuple4{1, 2, 3, 4});
+ static_assert(round_trip<tuple4>(b));
+}
+
+void test_partially_initialized() {
+ struct pad {
+ char x;
+ int y;
+ };
+
+ struct no_pad {
+ char x;
+ char p1, p2, p3; // expected-note {{subobject declared here}}
+ int y;
+ };
+
+ static_assert(sizeof(pad) == sizeof(no_pad));
+
+ constexpr pad pir{4, 4};
+ constexpr int piw = bit_cast<no_pad>(pir).x;
+ static_assert(piw == 4);
+
+ // expected-error@+2 {{constexpr variable 'bad' must be initialized by a constant expression}}
+ // expected-note@+1 {{subobject of type 'char' is not initialized}}
+ constexpr no_pad bad = bit_cast<no_pad>(pir);
+
+ constexpr pad fine = bit_cast<pad>(no_pad{1, 2, 3, 4, 5});
+ static_assert(fine.x == 1 && fine.y == 5);
+}
+
+void no_bitfields() {
+ // FIXME!
+ struct S {
+ unsigned char x : 8;
+ };
+
+ struct G {
+ unsigned char x : 8;
+ };
+
+ constexpr S s{0};
+ // expected-error@+2 {{constexpr variable 'g' must be initialized by a constant expression}}
+ // expected-note@+1 {{constexpr bit_cast involving bit-field in not yet supported}}
+ constexpr G g = __builtin_bit_cast(G, s);
+}
+
+void array_members() {
+ struct S {
+ int ar[3];
+
+ constexpr bool operator==(const S &rhs) {
+ return ar[0] == rhs.ar[0] && ar[1] == rhs.ar[1] && ar[2] == rhs.ar[2];
+ }
+ };
+
+ struct G {
+ int a, b, c;
+
+ constexpr bool operator==(const G &rhs) {
+ return a == rhs.a && b == rhs.b && c == rhs.c;
+ }
+ };
+
+ constexpr S s{{1, 2, 3}};
+ constexpr G g = bit_cast<G>(s);
+ static_assert(g.a == 1 && g.b == 2 && g.c == 3);
+
+ static_assert(round_trip<G>(s));
+ static_assert(round_trip<S>(g));
+}
+
+void bad_types() {
+ union X {
+ int x;
+ };
+
+ struct G {
+ int g;
+ };
+ // expected-error@+2 {{constexpr variable 'g' must be initialized by a constant expression}}
+ // expected-note@+1 {{cannot constexpr evaluate a bit_cast with a union type 'X'}}
+ constexpr G g = __builtin_bit_cast(G, X{0});
+ // expected-error@+2 {{constexpr variable 'x' must be initialized by a constant expression}}
+ // expected-note@+1 {{cannot constexpr evaluate a bit_cast with a union type 'X'}}
+ constexpr X x = __builtin_bit_cast(X, G{0});
+
+ struct has_pointer {
+ // expected-note@+1 2 {{invalid type 'int *' is a member of 'has_pointer'}}
+ int *ptr;
+ };
+
+ // expected-error@+2 {{constexpr variable 'ptr' must be initialized by a constant expression}}
+ // expected-note@+1 {{cannot constexpr evaluate a bit_cast with a pointer type 'int *'}}
+ constexpr unsigned long ptr = __builtin_bit_cast(unsigned long, has_pointer{0});
+ // expected-error@+2 {{constexpr variable 'hptr' must be initialized by a constant expression}}
+ // expected-note@+1 {{cannot constexpr evaluate a bit_cast with a pointer type 'int *'}}
+ constexpr has_pointer hptr = __builtin_bit_cast(has_pointer, 0ul);
+}
+
+void backtrace() {
+ struct A {
+ // expected-note@+1 {{invalid type 'int *' is a member of 'A'}}
+ int *ptr;
+ };
+
+ struct B {
+ // expected-note@+1 {{invalid type 'A [10]' is a member of 'B'}}
+ A as[10];
+ };
+
+ // expected-note@+1 {{invalid type 'B' is a base of 'C'}}
+ struct C : B {
+ };
+
+ struct E {
+ unsigned long ar[10];
+ };
+
+ // expected-error@+2 {{constexpr variable 'e' must be initialized by a constant expression}}
+ // expected-note@+1 {{cannot constexpr evaluate a bit_cast with a pointer type 'int *'}}
+ constexpr E e = __builtin_bit_cast(E, C{});
+}
Index: clang/test/SemaCXX/builtin-bit-cast.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/builtin-bit-cast.cpp
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -verify -std=c++2a -fsyntax-only -triple x86_64-apple-macosx10.14.0 %s
+
+template <class T, T v>
+T instantiate() {
+ return __builtin_bit_cast(T, v);
+}
+
+int x = instantiate<int, 32>();
+
+struct secret_ctor {
+ char member;
+
+private: secret_ctor() = default;
+};
+
+void test1() {
+ secret_ctor c = __builtin_bit_cast(secret_ctor, (char)0);
+}
+
+void test2() {
+ constexpr int i = 0;
+ // expected-error@+1{{__builtin_bit_cast source size does not match destination size (4 and 1)}}
+ constexpr char c = __builtin_bit_cast(char, i);
+}
Index: clang/test/CodeGenCXX/builtin-bit-cast.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/builtin-bit-cast.cpp
@@ -0,0 +1,112 @@
+// RUN: %clang_cc1 -std=c++2a -S -emit-llvm -o - -disable-llvm-passes -triple x86_64-apple-macos10.14 %s | FileCheck %s
+
+void test_scalar() {
+ // CHECK-LABEL: define void @_Z11test_scalarv
+
+ __builtin_bit_cast(float, 43);
+
+ // CHECK: [[BIT_CAST_TEMP_INT:%.*]] = alloca i32, align 4
+ // CHECK: [[BIT_CAST_TEMP_FLOAT:%.*]] = alloca float, align 4
+
+ // CHECK: store i32 43, i32* [[BIT_CAST_TEMP_INT]], align 4
+ // ...bitcast the memcpy operands to i8*...
+ // CHECK: call void @llvm.memcpy.p0i8.p0i8.i64
+ // CHECK-NEXT: [[TMP:%.*]] = bitcast i8* %1 to float*
+ // CHECK-NEXT: load float, float* [[TMP]], align 4
+}
+
+struct two_ints {
+ int x;
+ int y;
+};
+
+void test_aggregate_to_scalar() {
+ // CHECK-LABEL: define void @_Z24test_aggregate_to_scalarv
+ __builtin_bit_cast(unsigned long, two_ints{11, 12});
+
+ // CHECK: [[SRC_TEMP:%.*]] = alloca %struct.two_ints, align 4
+ // CHECK-NEXT: [[DST_TEMP:%.*]] = alloca i64, align 8
+ // CHECK: store i32 11, i32* {{.*}}, align 4
+ // CHECK: store i32 12, i32* {{.*}}, align 4
+ // ...bitcast the memcpy operands to i8*...
+ // CHECK: call void @llvm.memcpy.p0i8.p0i8.i64
+
+ // CHECK: [[TMP:%.*]] = bitcast i8* {{.*}} to i64*
+ // load i64, i64* [[TMP]], align 8
+}
+
+void test_aggregate_to_scalar_lv() {
+ // CHECK-LABEL: define void @_Z27test_aggregate_to_scalar_lvv
+ two_ints lv{11, 12}; // CHECK: alloca
+ __builtin_bit_cast(unsigned long, lv);
+
+ // CHECK: [[SOURCE:%.*]] = alloca %struct.two_ints, align 4
+ // CHECK-NEXT: [[DEST:%.*]] = alloca i64, align 8
+ // CHECK-NEXT: [[LVTMP:%.*]] = bitcast %struct.two_ints* {{.*}} to i8*
+ // CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 [[LVTMP]]
+ // CHECK: [[SRC_TEMP:%.*]] = bitcast %struct.two_ints* [[SOURCE]] to i8*
+ // CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 [[SRC_TEMP]]
+ // CHECK: bitcast
+ // CHECK: [[DEST_TEMP:%.*]] = bitcast i64* [[DEST]] to i8*
+ // CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 8 [[DEST_TEMP]]
+}
+
+struct two_floats {
+ float x;
+ float y;
+};
+
+void test_aggregate_record() {
+ // CHECK-LABEL: define void @_Z21test_aggregate_recordv
+ two_floats tf = __builtin_bit_cast(two_floats, two_ints{1, 2});
+
+ // CHECK: [[TF:%.*]] = alloca %struct.two_floats, align 4
+ // CHECK-NEXT: [[TFTMP:%.*]] = bitcast %struct.two_floats* [[TF]] to i8*
+ // CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 [[TFTMP]],
+}
+
+void test_aggregate_array() {
+ // CHECK-LABEL: define void @_Z20test_aggregate_arrayv
+ two_floats tf = __builtin_bit_cast(two_floats, (int [2]) {42, 32});
+
+ // CHECK: [[TF:%.*]] = alloca %struct.two_floats, align 4
+ // CHECK-NEXT: [[TFTMP:%.*]] = bitcast %struct.two_floats* [[TF]] to i8*
+ // CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 [[TFTMP]],
+}
+
+void test_scalar_to_aggregate() {
+ // CHECK-LABEL: define void @_Z24test_scalar_to_aggregatev
+ two_ints ti = __builtin_bit_cast(two_ints, 24ul);
+
+ // CHECK: [[TI:%.*]] = alloca %struct.two_ints, align 4
+ // CHECK-NEXT: [[TITMP:%.*]] = bitcast %struct.two_ints* [[TI]] to i8*
+ // CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 [[TITMP]]
+}
+
+void test_complex() {
+ // CHECK-LABEL: define void @_Z12test_complexv
+ using complex_t = _Complex unsigned;
+ __builtin_bit_cast(unsigned long, complex_t(43));
+
+ // CHECK: [[SOURCE:%.*]] = alloca { i32, i32 }, align 4
+ // CHECK-NEXT: [[DEST:%.*]] = alloca i64, align 8
+ // CHECK: bitcast { i32, i32 }* [[SOURCE]] to i8*
+ // CHECK-NEXT: [[DEST_TEMP:%.*]] = bitcast i64* [[DEST]] to i8*
+ // CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 8 [[DEST_TEMP]]
+}
+
+void test_to_complex() {
+ // CHECK-LABEL: define void @_Z15test_to_complexv
+
+ using complex_t = _Complex unsigned;
+ auto ul = __builtin_bit_cast(complex_t, 32ul);
+
+ // CHECK: [[UL:%.*]] = alloca { i32, i32 }
+ // CHECK-NEXT: [[BC_SRC:%.*]] = alloca i64, align 8
+ // CHECK-NEXT: [[BC_DST:%.*]] = alloca { i32, i32 }, align 4
+ // CHECK-NEXT: store i64 32, i64* [[BC_SRC]], align 8
+ // CHECK-NEXT: bitcast i64* [[BC_SRC]] to i8*
+ // CHECK-NEXT: [[DST_TEMP:%.*]] = bitcast { i32, i32 }* [[BC_DST]] to i8*
+ // CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 [[DST_TEMP]]
+ // CHECK-NEXT: bitcast i8* [[DST_TEMP]] to { i32, i32 }*
+}
Index: clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -376,6 +376,7 @@
case CK_Dependent:
case CK_ArrayToPointerDecay:
case CK_BitCast:
+ case CK_CXXBitCast:
case CK_AddressSpaceConversion:
case CK_BooleanToSignedIntegral:
case CK_NullToPointer:
Index: clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -1288,7 +1288,8 @@
case Stmt::OMPTargetTeamsDistributeParallelForDirectiveClass:
case Stmt::OMPTargetTeamsDistributeParallelForSimdDirectiveClass:
case Stmt::OMPTargetTeamsDistributeSimdDirectiveClass:
- case Stmt::CapturedStmtClass: {
+ case Stmt::CapturedStmtClass:
+ case Stmt::BuiltinBitCastExprClass: {
const ExplodedNode *node = Bldr.generateSink(S, Pred, Pred->getState());
Engine.addAbortedBlock(node, currBldrCtx->getBlock());
break;
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===================================================================
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1432,6 +1432,12 @@
Code = serialization::EXPR_CXX_FUNCTIONAL_CAST;
}
+void ASTStmtWriter::VisitBuiltinBitCastExpr(BuiltinBitCastExpr *E) {
+ VisitExplicitCastExpr(E);
+ Record.AddSourceLocation(E->getBeginLoc());
+ Record.AddSourceLocation(E->getEndLoc());
+}
+
void ASTStmtWriter::VisitUserDefinedLiteral(UserDefinedLiteral *E) {
VisitCallExpr(E);
Record.AddSourceLocation(E->UDSuffixLoc);
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===================================================================
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -1458,6 +1458,12 @@
E->setRParenLoc(ReadSourceLocation());
}
+void ASTStmtReader::VisitBuiltinBitCastExpr(BuiltinBitCastExpr *E) {
+ VisitExplicitCastExpr(E);
+ E->KWLoc = ReadSourceLocation();
+ E->RParenLoc = ReadSourceLocation();
+}
+
void ASTStmtReader::VisitUserDefinedLiteral(UserDefinedLiteral *E) {
VisitCallExpr(E);
E->UDSuffixLoc = ReadSourceLocation();
Index: clang/lib/Sema/TreeTransform.h
===================================================================
--- clang/lib/Sema/TreeTransform.h
+++ clang/lib/Sema/TreeTransform.h
@@ -10244,6 +10244,22 @@
E->getAngleBrackets().getEnd(), SubExpr.get(), E->getRParenLoc());
}
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformBuiltinBitCastExpr(BuiltinBitCastExpr *BCE) {
+ TypeSourceInfo *TSI =
+ getDerived().TransformType(BCE->getTypeInfoAsWritten());
+ if (!TSI)
+ return ExprError();
+
+ ExprResult Sub = getDerived().TransformExpr(BCE->getSubExpr());
+ if (Sub.isInvalid())
+ return ExprError();
+
+ return getSema().BuildBuiltinBitCastExpr(BCE->getBeginLoc(), TSI, Sub.get(),
+ BCE->getEndLoc());
+}
+
template<typename Derived>
ExprResult
TreeTransform<Derived>::TransformCXXStaticCastExpr(CXXStaticCastExpr *E) {
Index: clang/lib/Sema/SemaExceptionSpec.cpp
===================================================================
--- clang/lib/Sema/SemaExceptionSpec.cpp
+++ clang/lib/Sema/SemaExceptionSpec.cpp
@@ -1204,6 +1204,7 @@
case Expr::ShuffleVectorExprClass:
case Expr::ConvertVectorExprClass:
case Expr::VAArgExprClass:
+ case Expr::BuiltinBitCastExprClass:
return canSubExprsThrow(*this, E);
// Some might be dependent for other reasons.
Index: clang/lib/Sema/SemaCast.cpp
===================================================================
--- clang/lib/Sema/SemaCast.cpp
+++ clang/lib/Sema/SemaCast.cpp
@@ -87,6 +87,7 @@
void CheckDynamicCast();
void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization);
void CheckCStyleCast();
+ void CheckBitCast();
void updatePartOfExplicitCastFlags(CastExpr *CE) {
// Walk down from the CE to the OrigSrcExpr, and mark all immediate
@@ -331,6 +332,38 @@
}
}
+ExprResult Sema::ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &D,
+ ExprResult Operand,
+ SourceLocation RParenLoc) {
+ assert(!D.isInvalidType());
+
+ TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, Operand.get()->getType());
+ if (D.isInvalidType())
+ return ExprError();
+
+ return BuildBuiltinBitCastExpr(KWLoc, TInfo, Operand.get(), RParenLoc);
+}
+
+ExprResult Sema::BuildBuiltinBitCastExpr(SourceLocation KWLoc,
+ TypeSourceInfo *TSI, Expr *Operand,
+ SourceLocation RParenLoc) {
+ CastOperation Op(*this, TSI->getType(), Operand);
+ Op.OpRange = SourceRange(KWLoc, RParenLoc);
+ TypeLoc TL = TSI->getTypeLoc();
+ Op.DestRange = SourceRange(TL.getBeginLoc(), TL.getEndLoc());
+
+ if (!Operand->isTypeDependent() && !TSI->getType()->isDependentType()) {
+ Op.CheckBitCast();
+ if (Op.SrcExpr.isInvalid())
+ return ExprError();
+ }
+
+ BuiltinBitCastExpr *BCE =
+ new (Context) BuiltinBitCastExpr(Op.ResultType, Op.ValueKind, Op.Kind,
+ Op.SrcExpr.get(), TSI, KWLoc, RParenLoc);
+ return Op.complete(BCE);
+}
+
/// Try to diagnose a failed overloaded cast. Returns true if
/// diagnostics were emitted.
static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT,
@@ -953,7 +986,7 @@
unsigned msg = diag::err_bad_cxx_cast_generic;
TryCastResult tcr =
- TryReinterpretCast(Self, SrcExpr, DestType,
+ TryReinterpretCast(Self, SrcExpr, DestType,
/*CStyle*/false, OpRange, msg, Kind);
if (tcr != TC_Success && msg != 0) {
if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
@@ -2764,6 +2797,40 @@
checkCastAlign();
}
+void CastOperation::CheckBitCast() {
+ if (isPlaceholder())
+ SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
+
+ if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() ||
+ SrcExpr.get()->isValueDependent())
+ return;
+
+ QualType SrcType = SrcExpr.get()->getType();
+ CharUnits DestSize = Self.Context.getTypeSizeInChars(DestType);
+ CharUnits SourceSize = Self.Context.getTypeSizeInChars(SrcType);
+ if (DestSize != SourceSize) {
+ Self.Diag(OpRange.getBegin(), diag::err_bit_cast_type_size_mismatch)
+ << (int)SourceSize.getQuantity() << (int)DestSize.getQuantity();
+ SrcExpr = ExprError();
+ return;
+ }
+
+ if (!DestType.isTriviallyCopyableType(Self.Context)) {
+ Self.Diag(OpRange.getBegin(), diag::err_bit_cast_non_trivially_copyable)
+ << 1;
+ SrcExpr = ExprError();
+ return;
+ }
+ if (!SrcType.isTriviallyCopyableType(Self.Context)) {
+ Self.Diag(OpRange.getBegin(), diag::err_bit_cast_non_trivially_copyable)
+ << 0;
+ SrcExpr = ExprError();
+ return;
+ }
+
+ Kind = CK_CXXBitCast;
+}
+
/// DiagnoseCastQual - Warn whenever casts discards a qualifiers, be it either
/// const, volatile or both.
static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
Index: clang/lib/Parse/ParseExprCXX.cpp
===================================================================
--- clang/lib/Parse/ParseExprCXX.cpp
+++ clang/lib/Parse/ParseExprCXX.cpp
@@ -3487,3 +3487,37 @@
ConsumeAnyToken();
return Result;
}
+
+/// Parse a __builtin_bit_cast(T, E).
+ExprResult Parser::ParseBuiltinBitCast() {
+ SourceLocation KWLoc = ConsumeToken();
+
+ BalancedDelimiterTracker T(*this, tok::l_paren);
+ if (T.expectAndConsume(diag::err_expected_lparen_after, "__builtin_bit_cast"))
+ return ExprError();
+
+ // Parse the common declaration-specifiers piece.
+ DeclSpec DS(AttrFactory);
+ ParseSpecifierQualifierList(DS);
+
+ // Parse the abstract-declarator, if present.
+ Declarator DeclaratorInfo(DS, DeclaratorContext::TypeNameContext);
+ ParseDeclarator(DeclaratorInfo);
+
+ if (ExpectAndConsume(tok::comma)) {
+ Diag(Tok.getLocation(), diag::err_expected) << tok::comma;
+ SkipUntil(tok::r_paren, StopAtSemi);
+ return ExprError();
+ }
+
+ ExprResult Operand = ParseExpression();
+
+ if (T.consumeClose())
+ return ExprError();
+
+ if (Operand.isInvalid() || DeclaratorInfo.isInvalidType())
+ return ExprError();
+
+ return Actions.ActOnBuiltinBitCastExpr(KWLoc, DeclaratorInfo, Operand,
+ T.getCloseLocation());
+}
Index: clang/lib/Parse/ParseExpr.cpp
===================================================================
--- clang/lib/Parse/ParseExpr.cpp
+++ clang/lib/Parse/ParseExpr.cpp
@@ -1223,6 +1223,9 @@
case tok::kw_static_cast:
Res = ParseCXXCasts();
break;
+ case tok::kw___builtin_bit_cast:
+ Res = ParseBuiltinBitCast();
+ break;
case tok::kw_typeid:
Res = ParseCXXTypeid();
break;
Index: clang/lib/Edit/RewriteObjCFoundationAPI.cpp
===================================================================
--- clang/lib/Edit/RewriteObjCFoundationAPI.cpp
+++ clang/lib/Edit/RewriteObjCFoundationAPI.cpp
@@ -1079,6 +1079,7 @@
case CK_BuiltinFnToFnPtr:
case CK_ZeroToOCLOpaqueType:
case CK_IntToOCLSampler:
+ case CK_CXXBitCast:
return false;
case CK_BooleanToSignedIntegral:
Index: clang/lib/CodeGen/CGExprScalar.cpp
===================================================================
--- clang/lib/CodeGen/CGExprScalar.cpp
+++ clang/lib/CodeGen/CGExprScalar.cpp
@@ -2040,7 +2040,8 @@
Value *Src = Visit(const_cast<Expr*>(E));
llvm::Type *SrcTy = Src->getType();
llvm::Type *DstTy = ConvertType(DestTy);
- if (SrcTy->isPtrOrPtrVectorTy() && DstTy->isPtrOrPtrVectorTy() &&
+ if (Kind != CK_CXXBitCast &&
+ SrcTy->isPtrOrPtrVectorTy() && DstTy->isPtrOrPtrVectorTy() &&
SrcTy->getPointerAddressSpace() != DstTy->getPointerAddressSpace()) {
llvm_unreachable("wrong cast for pointers in different address spaces"
"(must be an address space cast)!");
@@ -2080,6 +2081,22 @@
return Builder.CreateBitCast(Src, DstTy);
}
+ case CK_CXXBitCast: {
+ Address Source = CGF.CreateIRTemp(E->getType(), "bit_cast.srctemp");
+ CGF.EmitAnyExprToMem(E, Source, E->getType().getQualifiers(),
+ /*isInit=*/false);
+ Address Dest = CGF.CreateIRTemp(DestTy, "bit_cast.dsttemp");
+ llvm::Value *Size = llvm::ConstantInt::get(
+ CGF.SizeTy, CGF.getContext().getTypeSizeInChars(DestTy).getQuantity());
+ bool IsVolatile =
+ E->getType().isVolatileQualified() || DestTy.isVolatileQualified();
+
+ Source = Builder.CreateElementBitCast(Source, CGF.Int8Ty);
+ Dest = Builder.CreateElementBitCast(Dest, CGF.Int8Ty);
+ Builder.CreateMemCpy(Dest, Source, Size, IsVolatile);
+ Dest = Builder.CreateElementBitCast(Dest, CGF.ConvertType(DestTy));
+ return EmitLoadOfLValue(CGF.MakeAddrLValue(Dest, DestTy), E->getExprLoc());
+ }
case CK_AddressSpaceConversion: {
Expr::EvalResult Result;
if (E->EvaluateAsRValue(Result, CGF.getContext()) &&
Index: clang/lib/CodeGen/CGExprConstant.cpp
===================================================================
--- clang/lib/CodeGen/CGExprConstant.cpp
+++ clang/lib/CodeGen/CGExprConstant.cpp
@@ -838,6 +838,7 @@
// These don't need to be handled here because Evaluate knows how to
// evaluate them in the cases where they can be folded.
case CK_BitCast:
+ case CK_CXXBitCast:
case CK_ToVoid:
case CK_Dynamic:
case CK_LValueBitCast:
Index: clang/lib/CodeGen/CGExprComplex.cpp
===================================================================
--- clang/lib/CodeGen/CGExprComplex.cpp
+++ clang/lib/CodeGen/CGExprComplex.cpp
@@ -464,6 +464,23 @@
return EmitLoadOfLValue(CGF.MakeAddrLValue(V, DestTy), Op->getExprLoc());
}
+ case CK_CXXBitCast: {
+ Address Source = CGF.CreateIRTemp(Op->getType(), "bit_cast.srctemp");
+ CGF.EmitAnyExprToMem(Op, Source, Op->getType().getQualifiers(),
+ /*isInit=*/false);
+ Address Dest = CGF.CreateIRTemp(DestTy, "bit_cast.dsttemp");
+ llvm::Value *Size = llvm::ConstantInt::get(
+ CGF.SizeTy, CGF.getContext().getTypeSizeInChars(DestTy).getQuantity());
+ bool IsVolatile =
+ Op->getType().isVolatileQualified() || DestTy.isVolatileQualified();
+
+ Source = Builder.CreateElementBitCast(Source, CGF.Int8Ty);
+ Dest = Builder.CreateElementBitCast(Dest, CGF.Int8Ty);
+ Builder.CreateMemCpy(Dest, Source, Size, IsVolatile);
+ Dest = Builder.CreateElementBitCast(Dest, CGF.ConvertType(DestTy));
+ return EmitLoadOfLValue(CGF.MakeAddrLValue(Dest, DestTy), Op->getExprLoc());
+ }
+
case CK_BitCast:
case CK_BaseToDerived:
case CK_DerivedToBase:
Index: clang/lib/CodeGen/CGExprAgg.cpp
===================================================================
--- clang/lib/CodeGen/CGExprAgg.cpp
+++ clang/lib/CodeGen/CGExprAgg.cpp
@@ -80,6 +80,8 @@
void EmitFinalDestCopy(QualType type, const LValue &src,
ExprValueKind SrcValueKind = EVK_NonRValue);
void EmitFinalDestCopy(QualType type, RValue src);
+ void EmitTrivialFinalDestCopy(QualType Ty, const LValue &Source);
+ void EmitTrivialFinalDestCopy(QualType Ty, RValue Source);
void EmitCopy(QualType type, const AggValueSlot &dest,
const AggValueSlot &src);
@@ -342,11 +344,20 @@
}
}
- AggValueSlot srcAgg =
- AggValueSlot::forLValue(src, AggValueSlot::IsDestructed,
- needsGC(type), AggValueSlot::IsAliased,
- AggValueSlot::MayOverlap);
- EmitCopy(type, Dest, srcAgg);
+ EmitTrivialFinalDestCopy(type, src);
+}
+
+void AggExprEmitter::EmitTrivialFinalDestCopy(QualType Ty, RValue Source) {
+ LValue SourceLValue = CGF.MakeAddrLValue(Source.getAggregateAddress(), Ty);
+ EmitTrivialFinalDestCopy(Ty, SourceLValue);
+}
+
+void AggExprEmitter::EmitTrivialFinalDestCopy(QualType Ty,
+ const LValue &Source) {
+ AggValueSlot srcAgg = AggValueSlot::forLValue(
+ Source, AggValueSlot::IsDestructed, needsGC(Ty),
+ AggValueSlot::IsAliased, AggValueSlot::MayOverlap);
+ EmitCopy(Ty, Dest, srcAgg);
}
/// Perform a copy from the source into the destination.
@@ -807,6 +818,25 @@
Visit(E->getSubExpr());
break;
+ case CK_CXXBitCast: {
+ if (Dest.isIgnored()) {
+ CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
+ /*IgnoreResult=*/true);
+ break;
+ }
+
+ QualType SourceType = E->getSubExpr()->getType();
+ QualType DestType = E->getType();
+ Address SourceTemp = CGF.CreateIRTemp(SourceType, "bit_cast.srctemp");
+ CGF.EmitAnyExprToMem(E->getSubExpr(), SourceTemp,
+ SourceType.getQualifiers(), false);
+ Address Casted =
+ Builder.CreateElementBitCast(SourceTemp, CGF.ConvertType(DestType));
+ RValue CastedRV =
+ RValue::getAggregate(Casted, DestType.isVolatileQualified());
+ return EmitTrivialFinalDestCopy(DestType, CastedRV);
+ }
+
case CK_LValueBitCast:
llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
Index: clang/lib/CodeGen/CGExpr.cpp
===================================================================
--- clang/lib/CodeGen/CGExpr.cpp
+++ clang/lib/CodeGen/CGExpr.cpp
@@ -4130,6 +4130,7 @@
switch (E->getCastKind()) {
case CK_ToVoid:
case CK_BitCast:
+ case CK_CXXBitCast:
case CK_ArrayToPointerDecay:
case CK_FunctionToPointerDecay:
case CK_NullToMemberPointer:
Index: clang/lib/AST/StmtProfile.cpp
===================================================================
--- clang/lib/AST/StmtProfile.cpp
+++ clang/lib/AST/StmtProfile.cpp
@@ -1569,6 +1569,11 @@
VisitCXXNamedCastExpr(S);
}
+void StmtProfiler::VisitBuiltinBitCastExpr(const BuiltinBitCastExpr *S) {
+ VisitExpr(S);
+ VisitType(S->getTypeInfoAsWritten()->getType());
+}
+
void StmtProfiler::VisitUserDefinedLiteral(const UserDefinedLiteral *S) {
VisitCallExpr(S);
}
Index: clang/lib/AST/StmtPrinter.cpp
===================================================================
--- clang/lib/AST/StmtPrinter.cpp
+++ clang/lib/AST/StmtPrinter.cpp
@@ -1710,6 +1710,14 @@
VisitCXXNamedCastExpr(Node);
}
+void StmtPrinter::VisitBuiltinBitCastExpr(BuiltinBitCastExpr *Node) {
+ OS << "__builtin_bit_cast(";
+ Node->getTypeInfoAsWritten()->getType().print(OS, Policy);
+ OS << ", ";
+ PrintExpr(Node->getSubExpr());
+ OS << ")";
+}
+
void StmtPrinter::VisitCXXTypeidExpr(CXXTypeidExpr *Node) {
OS << "typeid(";
if (Node->isTypeOperand()) {
Index: clang/lib/AST/ItaniumMangle.cpp
===================================================================
--- clang/lib/AST/ItaniumMangle.cpp
+++ clang/lib/AST/ItaniumMangle.cpp
@@ -3618,6 +3618,7 @@
case Expr::AtomicExprClass:
case Expr::SourceLocExprClass:
case Expr::FixedPointLiteralClass:
+ case Expr::BuiltinBitCastExprClass:
{
if (!NullOut) {
// As bad as this diagnostic is, it's better than crashing.
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -48,6 +48,7 @@
#include "clang/Basic/FixedPoint.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/Support/SaveAndRestore.h"
+#include "llvm/ADT/Optional.h"
#include "llvm/Support/raw_ostream.h"
#include <cstring>
#include <functional>
@@ -55,8 +56,10 @@
#define DEBUG_TYPE "exprconstant"
using namespace clang;
+using llvm::APInt;
using llvm::APSInt;
using llvm::APFloat;
+using llvm::Optional;
static bool IsGlobalLValue(APValue::LValueBase B);
@@ -5350,6 +5353,418 @@
//===----------------------------------------------------------------------===//
namespace {
+class APBuffer {
+ // FIXME: We're going to need bit-level granularity when we support
+ // bit-fields.
+ SmallVector<Optional<unsigned char>, 32> Bytes;
+
+ bool TargetIsLittleEndian;
+
+public:
+ APBuffer(CharUnits Width, bool TargetIsLittleEndian)
+ : Bytes(Width.getQuantity()),
+ TargetIsLittleEndian(TargetIsLittleEndian) {}
+
+ bool readObject(CharUnits Offset, CharUnits Width,
+ SmallVectorImpl<unsigned char> &Output) const {
+ for (CharUnits I = Offset, E = Offset + Width; I != E; ++I) {
+ // If a byte of an integer is uninitialized, then the whole integer is
+ // uninitalized.
+ if (!Bytes[I.getQuantity()])
+ return false;
+ Output.push_back(*Bytes[I.getQuantity()]);
+ }
+ if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
+ std::reverse(Output.begin(), Output.end());
+ return true;
+ }
+
+ void writeObject(CharUnits Offset, SmallVectorImpl<unsigned char> &Input) {
+ if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
+ std::reverse(Input.begin(), Input.end());
+
+ size_t Index = 0;
+ for (unsigned char Byte : Input) {
+ assert(!Bytes[Offset.getQuantity() + Index] && "overwriting a byte?");
+ Bytes[Offset.getQuantity() + Index] = Byte;
+ ++Index;
+ }
+ }
+
+ size_t size() { return Bytes.size(); }
+};
+
+// Traverse an APValue to produce an APBuffer, emulating how the current target
+// would represent the value at runtime.
+class BitCastReader {
+ EvalInfo &Info;
+ APBuffer Buffer;
+ const CastExpr *BCE;
+
+ BitCastReader(EvalInfo &Info, CharUnits ObjectWidth, const CastExpr *BCE)
+ : Info(Info),
+ Buffer(ObjectWidth, Info.Ctx.getTargetInfo().isLittleEndian()),
+ BCE(BCE) {}
+
+ bool visit(const APValue &Val, QualType Ty) {
+ return visit(Val, Ty, CharUnits::fromQuantity(0));
+ }
+
+ // Write out Val with type Ty into Buffer starting at Offset.
+ bool visit(const APValue &Val, QualType Ty, CharUnits Offset) {
+ assert((size_t)Offset.getQuantity() <= Buffer.size());
+
+ // Dig through Src to find the byte at SrcOffset.
+ switch (Val.getKind()) {
+ case APValue::Indeterminate:
+ case APValue::None:
+ Info.FFDiag(BCE->getBeginLoc(), diag::note_constexpr_uninitialized)
+ << true << Ty;
+ return false;
+
+ case APValue::Int:
+ return visitInt(Val.getInt(), Ty, Offset);
+ case APValue::Float:
+ return visitFloat(Val.getFloat(), Ty, Offset);
+ case APValue::Array:
+ return visitArray(Val, Ty, Offset);
+ case APValue::Struct:
+ return visitRecord(Val, Ty, Offset);
+
+ case APValue::ComplexInt:
+ case APValue::ComplexFloat:
+ case APValue::Vector:
+ case APValue::Union:
+ case APValue::MemberPointer:
+ case APValue::AddrLabelDiff:
+ case APValue::FixedPoint: {
+ Info.FFDiag(BCE->getBeginLoc(),
+ diag::note_constexpr_bit_cast_unsupported_type)
+ << Ty;
+ return false;
+ }
+
+ case APValue::LValue: {
+ LValue LVal;
+ LVal.setFrom(Info.Ctx, Val);
+ APValue RVal;
+ if (!handleLValueToRValueConversion(Info, BCE, Ty.withConst(),
+ LVal, RVal))
+ return false;
+ return visit(RVal, Ty, Offset);
+ }
+ }
+ }
+
+ bool visitRecord(const APValue &Val, QualType Ty, CharUnits Offset) {
+ const RecordDecl *RD = Ty->getAsRecordDecl();
+ const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
+
+ // Visit the base classes.
+ if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
+ for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
+ const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
+ CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
+
+ if (!visitRecord(Val.getStructBase(I), BS.getType(),
+ Layout.getBaseClassOffset(BaseDecl) + Offset))
+ return false;
+ }
+ }
+
+ // Visit the fields.
+ unsigned FieldIdx = 0;
+ for (FieldDecl *FD : RD->fields()) {
+ if (FD->isBitField()) {
+ Info.FFDiag(BCE->getBeginLoc(),
+ diag::note_constexpr_bit_cast_unsupported_bitfield);
+ return false;
+ }
+
+ uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);
+
+ assert(FieldOffsetBits % 8 == 0 &&
+ "only bit-fields can have sub-char alignment");
+ CharUnits FieldOffset =
+ CharUnits::fromQuantity(FieldOffsetBits / 8) + Offset;
+ QualType FieldTy = FD->getType();
+ if (!visit(Val.getStructField(FieldIdx), FieldTy, FieldOffset))
+ return false;
+ ++FieldIdx;
+ }
+
+ return true;
+ }
+
+ bool visitArray(const APValue &Val, QualType Ty, CharUnits Offset) {
+ const auto *CAT =
+ dyn_cast_or_null<ConstantArrayType>(Ty->getAsArrayTypeUnsafe());
+ if (!CAT)
+ return false;
+ CharUnits ElemWidth = Info.Ctx.getTypeSizeInChars(CAT->getElementType());
+ expandArray(const_cast<APValue &>(Val), Val.getArraySize()-1);
+ for (unsigned I = 0, E = Val.getArraySize(); I != E; ++I) {
+ const APValue &SubObj = Val.getArrayInitializedElt(I);
+ if (!visit(SubObj, CAT->getElementType(), Offset + I * ElemWidth))
+ return false;
+ }
+ return true;
+ }
+
+ bool visitInt(const APSInt &Val, QualType Ty, CharUnits Offset) {
+ CharUnits Width = Info.Ctx.getTypeSizeInChars(Ty);
+ SmallVector<unsigned char, 8> Bytes(Width.getQuantity());
+ llvm::StoreIntToMemory(Val, &*Bytes.begin(), Width.getQuantity());
+ Buffer.writeObject(Offset, Bytes);
+ return true;
+ }
+
+ bool visitFloat(const APFloat &Val, QualType Ty, CharUnits Offset) {
+ APSInt AsInt(Val.bitcastToAPInt());
+ return visitInt(AsInt, Ty, Offset);
+ }
+
+public:
+ static Optional<APBuffer> read(EvalInfo &Info, const APValue &Src,
+ const CastExpr *BCE) {
+ CharUnits DstSize = Info.Ctx.getTypeSizeInChars(BCE->getType());
+ BitCastReader Reader(Info, DstSize, BCE);
+ if (!Reader.visit(Src, BCE->getSubExpr()->getType()))
+ return None;
+ return Reader.Buffer;
+ }
+};
+
+class BitCastWriter {
+ EvalInfo &Info;
+ const APBuffer &Buffer;
+ const CastExpr *BCE;
+
+ BitCastWriter(EvalInfo &Info, const APBuffer &Buffer, const CastExpr *BCE)
+ : Info(Info), Buffer(Buffer), BCE(BCE) {}
+
+ // Emit an unsupported bit_cast type error. Sema refuses to build a bit_cast
+ // with an invalid type, so anything left is a deficiency on our part (FIXME).
+ // Ideally this will be unreachable.
+ llvm::NoneType unsupportedType(QualType Ty) {
+ Info.FFDiag(BCE->getBeginLoc(),
+ diag::note_constexpr_bit_cast_unsupported_type)
+ << Ty;
+ return None;
+ }
+
+ Optional<APValue> visit(const BuiltinType *T, CharUnits Offset) {
+ CharUnits SizeOf = Info.Ctx.getTypeSizeInChars(T);
+ SmallVector<uint8_t, 8> Bytes;
+ if (!Buffer.readObject(Offset, SizeOf, Bytes))
+ return APValue();
+
+ APSInt Val(SizeOf.getQuantity() * 8, true);
+ llvm::LoadIntFromMemory(Val, &*Bytes.begin(), Bytes.size());
+
+ if (T->isIntegralOrEnumerationType()) {
+ Val.setIsSigned(T->isSignedIntegerOrEnumerationType());
+ return APValue(Val);
+ }
+
+ if (T->isRealFloatingType()) {
+ const llvm::fltSemantics &Semantics =
+ Info.Ctx.getFloatTypeSemantics(QualType(T, 0));
+ return APValue(APFloat(Semantics, Val));
+ }
+
+ return unsupportedType(QualType(T, 0));
+ }
+
+ Optional<APValue> visit(const RecordType *RTy, CharUnits Offset) {
+ const RecordDecl *RD = RTy->getAsRecordDecl();
+ const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
+
+ unsigned NumBases = 0;
+ if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
+ NumBases = CXXRD->getNumBases();
+
+ APValue ResultVal(APValue::UninitStruct(), NumBases,
+ std::distance(RD->field_begin(), RD->field_end()));
+
+ // Visit the base classes.
+ if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
+ for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
+ const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
+ CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
+ if (BaseDecl->isEmpty() ||
+ Info.Ctx.getASTRecordLayout(BaseDecl).getNonVirtualSize().isZero())
+ continue;
+
+ Optional<APValue> SubObj = visitType(
+ BS.getType(), Layout.getBaseClassOffset(BaseDecl) + Offset);
+ if (!SubObj)
+ return None;
+ ResultVal.getStructBase(I) = *SubObj;
+ }
+ }
+
+ // Visit the fields.
+ unsigned FieldIdx = 0;
+ for (FieldDecl *FD : RD->fields()) {
+ // FIXME: We don't currently support bit-fields. A lot of the logic for
+ // this is in CodeGen, so we need to factor it around.
+ if (FD->isBitField()) {
+ Info.FFDiag(BCE->getBeginLoc(),
+ diag::note_constexpr_bit_cast_unsupported_bitfield);
+ return None;
+ }
+
+ uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);
+ assert(FieldOffsetBits % 8 == 0);
+
+ CharUnits FieldOffset =
+ CharUnits::fromQuantity(FieldOffsetBits / 8) + Offset;
+ QualType FieldTy = FD->getType();
+ Optional<APValue> SubObj = visitType(FieldTy, FieldOffset);
+ if (!SubObj)
+ return None;
+ ResultVal.getStructField(FieldIdx) = *SubObj;
+ ++FieldIdx;
+ }
+
+ return ResultVal;
+ }
+
+ Optional<APValue> visit(const EnumType *Ty, CharUnits Offset) {
+ QualType RepresentationType = Ty->getDecl()->getIntegerType();
+ assert(!RepresentationType.isNull() &&
+ "enum forward decl should be caught by Sema");
+ return visitType(RepresentationType, Offset);
+ }
+
+ Optional<APValue> visit(const ConstantArrayType *Ty, CharUnits Offset) {
+ size_t Size = Ty->getSize().getLimitedValue();
+ CharUnits ElementWidth = Info.Ctx.getTypeSizeInChars(Ty->getElementType());
+
+ APValue ArrayValue(APValue::UninitArray(), Size, Size);
+ for (size_t I = 0; I != Size; ++I) {
+ Optional<APValue> ElementValue =
+ visitType(Ty->getElementType(), Offset + I * ElementWidth);
+ if (!ElementValue)
+ return None;
+ ArrayValue.getArrayInitializedElt(I) = std::move(*ElementValue);
+ }
+
+ return ArrayValue;
+ }
+
+ Optional<APValue> visit(const Type *Ty, CharUnits Offset) {
+ return unsupportedType(QualType(Ty, 0));
+ }
+
+ Optional<APValue> visitType(QualType Ty, CharUnits Offset) {
+ QualType Can = Ty.getCanonicalType();
+
+ switch (Can->getTypeClass()) {
+#define TYPE(Class, Base) \
+ case Type::Class: \
+ return visit(cast<Class##Type>(Can.getTypePtr()), Offset);
+#define ABSTRACT_TYPE(Class, Base)
+#define NON_CANONICAL_TYPE(Class, Base) \
+ case Type::Class: \
+ llvm_unreachable("non-canonical type should be impossible!");
+#define DEPENDENT_TYPE(Class, Base) \
+ case Type::Class: \
+ llvm_unreachable( \
+ "dependent types aren't supported in the constant evaluator!");
+#define NON_CANONICAL_UNLESS_DEPENDENT(Class, Base) \
+ case Type::Class: \
+ llvm_unreachable("either dependent or not canonical!");
+#include "clang/AST/TypeNodes.def"
+ }
+ }
+
+public:
+ // Pull out a full value of type DstType.
+ static Optional<APValue> write(EvalInfo &Info, APBuffer &Buffer,
+ const CastExpr *BCE) {
+ BitCastWriter Writer(Info, Buffer, BCE);
+ return Writer.visitType(BCE->getType(), CharUnits::fromQuantity(0));
+ }
+};
+
+static bool checkBitCastConstexprEligibilityType(SourceLocation Loc,
+ QualType Ty, EvalInfo *Info,
+ const ASTContext &Ctx) {
+ Ty = Ty.getCanonicalType();
+
+ auto diag = [&](int Reason) {
+ if (Info)
+ Info->FFDiag(Loc, diag::note_constexpr_bit_cast_invalid_type)
+ << Reason << Ty;
+ return false;
+ };
+ auto note = [&](int Construct, QualType NoteTy, SourceLocation NoteLoc) {
+ if (Info)
+ Info->Note(NoteLoc, diag::note_constexpr_bit_cast_invalid_subtype)
+ << NoteTy << Construct << Ty;
+ return false;
+ };
+
+ if (Ty->isUnionType())
+ return diag(0);
+ if (Ty->isPointerType())
+ return diag(1);
+ if (Ty->isMemberPointerType())
+ return diag(2);
+ if (Ty.isVolatileQualified())
+ return diag(3);
+
+ if (RecordDecl *Record = Ty->getAsRecordDecl()) {
+ if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Record)) {
+ for (CXXBaseSpecifier &BS : CXXRD->bases())
+ if (!checkBitCastConstexprEligibilityType(Loc, BS.getType(), Info, Ctx))
+ return note(1, BS.getType(), BS.getBeginLoc());
+ }
+ for (FieldDecl *FD : Record->fields()) {
+ if (!checkBitCastConstexprEligibilityType(Loc, FD->getType(), Info, Ctx))
+ return note(0, FD->getType(), FD->getBeginLoc());
+ }
+ }
+
+ if (Ty->isArrayType() && !checkBitCastConstexprEligibilityType(
+ Loc, Ctx.getBaseElementType(Ty), Info, Ctx))
+ return false;
+
+ return true;
+}
+
+static bool checkBitCastConstexprEligibility(EvalInfo *Info,
+ const ASTContext &Ctx,
+ const CastExpr *BCE) {
+ bool DestOK = checkBitCastConstexprEligibilityType(BCE->getBeginLoc(),
+ BCE->getType(), Info, Ctx);
+ bool SourceOK = DestOK && checkBitCastConstexprEligibilityType(
+ BCE->getBeginLoc(),
+ BCE->getSubExpr()->getType(), Info, Ctx);
+ return SourceOK;
+}
+
+static bool handleBitCast(EvalInfo &Info, APValue &DestValue,
+ APValue &SourceValue, const CastExpr *BCE) {
+ if (!checkBitCastConstexprEligibility(&Info, Info.Ctx, BCE))
+ return false;
+
+ // Read out SourceValue into a char buffer.
+ Optional<APBuffer> Buffer = BitCastReader::read(Info, SourceValue, BCE);
+ if (!Buffer)
+ return false;
+
+ // Write out the buffer into a new APValue.
+ Optional<APValue> MaybeDestValue = BitCastWriter::write(Info, *Buffer, BCE);
+ if (!MaybeDestValue)
+ return false;
+
+ DestValue = std::move(*MaybeDestValue);
+ return true;
+}
+
template <class Derived>
class ExprEvaluatorBase
: public ConstStmtVisitor<Derived, bool> {
@@ -5484,6 +5899,9 @@
CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
return static_cast<Derived*>(this)->VisitCastExpr(E);
}
+ bool VisitBuiltinBitCastExpr(const BuiltinBitCastExpr *E) {
+ return static_cast<Derived*>(this)->VisitCastExpr(E);
+ }
bool VisitBinaryOperator(const BinaryOperator *E) {
switch (E->getOpcode()) {
@@ -5776,6 +6194,14 @@
return false;
return DerivedSuccess(RVal, E);
}
+ case CK_CXXBitCast: {
+ APValue DestValue, SourceValue;
+ if (!Evaluate(SourceValue, Info, E->getSubExpr()))
+ return false;
+ if (!handleBitCast(Info, DestValue, SourceValue, E))
+ return false;
+ return DerivedSuccess(DestValue, E);
+ }
}
return Error(E);
@@ -10570,6 +10996,7 @@
case CK_LValueToRValue:
case CK_AtomicToNonAtomic:
case CK_NoOp:
+ case CK_CXXBitCast:
return ExprEvaluatorBaseTy::VisitCastExpr(E);
case CK_MemberPointerToBoolean:
@@ -11182,6 +11609,7 @@
case CK_LValueToRValue:
case CK_AtomicToNonAtomic:
case CK_NoOp:
+ case CK_CXXBitCast:
return ExprEvaluatorBaseTy::VisitCastExpr(E);
case CK_Dependent:
@@ -12477,6 +12905,11 @@
case Expr::ChooseExprClass: {
return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx);
}
+ case Expr::BuiltinBitCastExprClass: {
+ if (!checkBitCastConstexprEligibility(nullptr, Ctx, cast<CastExpr>(E)))
+ return ICEDiag(IK_NotICE, E->getBeginLoc());
+ return CheckICE(cast<CastExpr>(E)->getSubExpr(), Ctx);
+ }
}
llvm_unreachable("Invalid StmtClass!");
Index: clang/lib/AST/ExprClassification.cpp
===================================================================
--- clang/lib/AST/ExprClassification.cpp
+++ clang/lib/AST/ExprClassification.cpp
@@ -420,6 +420,8 @@
case Expr::CoawaitExprClass:
case Expr::CoyieldExprClass:
return ClassifyInternal(Ctx, cast<CoroutineSuspendExpr>(E)->getResumeExpr());
+ case Expr::BuiltinBitCastExprClass:
+ return Cl::CL_PRValue;
}
llvm_unreachable("unhandled expression kind in classification");
Index: clang/lib/AST/Expr.cpp
===================================================================
--- clang/lib/AST/Expr.cpp
+++ clang/lib/AST/Expr.cpp
@@ -1739,6 +1739,7 @@
case CK_UserDefinedConversion: // operator bool()
case CK_BuiltinFnToFnPtr:
case CK_FixedPointToBoolean:
+ case CK_CXXBitCast:
CheckNoBasePath:
assert(path_empty() && "Cast kind should not have a base path!");
break;
@@ -3450,6 +3451,9 @@
if (IncludePossibleEffects)
return true;
break;
+ case BuiltinBitCastExprClass:
+ return cast<BuiltinBitCastExpr>(this)->getSubExpr()->HasSideEffects(
+ Ctx, IncludePossibleEffects);
}
// Recurse to children.
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -5194,6 +5194,13 @@
SourceRange AngleBrackets,
SourceRange Parens);
+ ExprResult ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &Dcl,
+ ExprResult Operand,
+ SourceLocation RParenLoc);
+
+ ExprResult BuildBuiltinBitCastExpr(SourceLocation KWLoc, TypeSourceInfo *TSI,
+ Expr *Operand, SourceLocation RParenLoc);
+
ExprResult BuildCXXTypeId(QualType TypeInfoType,
SourceLocation TypeidLoc,
TypeSourceInfo *Operand,
Index: clang/include/clang/Parse/Parser.h
===================================================================
--- clang/include/clang/Parse/Parser.h
+++ clang/include/clang/Parse/Parser.h
@@ -3059,6 +3059,9 @@
unsigned ArgumentIndex) override;
void CodeCompleteIncludedFile(llvm::StringRef Dir, bool IsAngled) override;
void CodeCompleteNaturalLanguage() override;
+
+ /// Parse a __builtin_bit_cast(T, E).
+ ExprResult ParseBuiltinBitCast();
};
} // end namespace clang
Index: clang/include/clang/Basic/TokenKinds.def
===================================================================
--- clang/include/clang/Basic/TokenKinds.def
+++ clang/include/clang/Basic/TokenKinds.def
@@ -669,7 +669,7 @@
KEYWORD(__builtin_convertvector , KEYALL)
ALIAS("__char16_t" , char16_t , KEYCXX)
ALIAS("__char32_t" , char32_t , KEYCXX)
-
+KEYWORD(__builtin_bit_cast , KEYALL)
KEYWORD(__builtin_available , KEYALL)
// Clang-specific keywords enabled only in testing.
Index: clang/include/clang/Basic/StmtNodes.td
===================================================================
--- clang/include/clang/Basic/StmtNodes.td
+++ clang/include/clang/Basic/StmtNodes.td
@@ -192,6 +192,7 @@
def BlockExpr : DStmt<Expr>;
def OpaqueValueExpr : DStmt<Expr>;
def TypoExpr : DStmt<Expr>;
+def BuiltinBitCastExpr : DStmt<ExplicitCastExpr>;
// Microsoft Extensions.
def MSPropertyRefExpr : DStmt<Expr>;
Index: clang/include/clang/Basic/Features.def
===================================================================
--- clang/include/clang/Basic/Features.def
+++ clang/include/clang/Basic/Features.def
@@ -249,6 +249,7 @@
EXTENSION(pragma_clang_attribute_namespaces, true)
EXTENSION(pragma_clang_attribute_external_declaration, true)
EXTENSION(gnu_asm, LangOpts.GNUAsm)
+EXTENSION(builtin_bit_cast, true)
#undef EXTENSION
#undef FEATURE
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -9712,4 +9712,8 @@
"%select{non-pointer|function pointer|void pointer}0 argument to "
"'__builtin_launder' is not allowed">;
+def err_bit_cast_non_trivially_copyable : Error<
+ "__builtin_bit_cast %select{source|destination}0 type must be a trivially copyable">;
+def err_bit_cast_type_size_mismatch : Error<
+ "__builtin_bit_cast source size does not match destination size (%0 and %1)">;
} // end of sema component.
Index: clang/include/clang/Basic/DiagnosticASTKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticASTKinds.td
+++ clang/include/clang/Basic/DiagnosticASTKinds.td
@@ -213,6 +213,15 @@
"size to copy (%4) is not a multiple of size of element type %3 (%5)|"
"source is not a contiguous array of at least %4 elements of type %3|"
"destination is not a contiguous array of at least %4 elements of type %3}2">;
+def note_constexpr_bit_cast_unsupported_type : Note<
+ "constexpr bit_cast involving type %0 is not yet supported">;
+def note_constexpr_bit_cast_unsupported_bitfield : Note<
+ "constexpr bit_cast involving bit-field in not yet supported">;
+def note_constexpr_bit_cast_invalid_type : Note<
+ "cannot constexpr evaluate a bit_cast with a "
+ "%select{union|pointer|member pointer|volatile}0 type %1">;
+def note_constexpr_bit_cast_invalid_subtype : Note<
+ "invalid type %0 is a %select{member|base}1 of %2">;
def warn_integer_constant_overflow : Warning<
"overflow in expression; result is %0 with type %1">,
Index: clang/include/clang/AST/RecursiveASTVisitor.h
===================================================================
--- clang/include/clang/AST/RecursiveASTVisitor.h
+++ clang/include/clang/AST/RecursiveASTVisitor.h
@@ -2282,6 +2282,10 @@
TRY_TO(TraverseTypeLoc(S->getTypeInfoAsWritten()->getTypeLoc()));
})
+DEF_TRAVERSE_STMT(BuiltinBitCastExpr, {
+ TRY_TO(TraverseTypeLoc(S->getTypeInfoAsWritten()->getTypeLoc()));
+})
+
template <typename Derived>
bool RecursiveASTVisitor<Derived>::TraverseSynOrSemInitListExpr(
InitListExpr *S, DataRecursionQueue *Queue) {
Index: clang/include/clang/AST/OperationKinds.def
===================================================================
--- clang/include/clang/AST/OperationKinds.def
+++ clang/include/clang/AST/OperationKinds.def
@@ -66,6 +66,12 @@
/// bool b; reinterpret_cast<char&>(b) = 'a';
CAST_OPERATION(LValueBitCast)
+/// CK_CXXBitCast - Represents std::bit_cast. Like CK_BitCast, but with very few
+/// semantic requirements, namely, the source and destination types just need to
+/// be of the same size and trivially copyable. There is no CK_LValueBitCast
+/// analog for this, since std::bit_cast isn't able to create a need for it.
+CAST_OPERATION(CXXBitCast)
+
/// CK_LValueToRValue - A conversion which causes the extraction of
/// an r-value from the operand gl-value. The result of an r-value
/// conversion is always unqualified.
Index: clang/include/clang/AST/ExprCXX.h
===================================================================
--- clang/include/clang/AST/ExprCXX.h
+++ clang/include/clang/AST/ExprCXX.h
@@ -4716,6 +4716,35 @@
}
};
+/// Represents a C++2a __builtin_bit_cast(T, v) expression. Used to implement
+/// std::bit_cast. These can sometimes be evaluated as part of a constant
+/// expression, but otherwise CodeGen to a simple memcpy in general.
+class BuiltinBitCastExpr final
+ : public ExplicitCastExpr,
+ private llvm::TrailingObjects<BuiltinBitCastExpr, CXXBaseSpecifier *> {
+ friend class ASTStmtReader;
+ friend class CastExpr;
+ friend class TrailingObjects;
+
+ SourceLocation KWLoc;
+ SourceLocation RParenLoc;
+
+public:
+ BuiltinBitCastExpr(QualType T, ExprValueKind VK, CastKind CK, Expr *SrcExpr,
+ TypeSourceInfo *DstType, SourceLocation KWLoc,
+ SourceLocation RParenLoc)
+ : ExplicitCastExpr(BuiltinBitCastExprClass, T, VK, CK, SrcExpr, 0,
+ DstType),
+ KWLoc(KWLoc), RParenLoc(RParenLoc) {}
+
+ SourceLocation getBeginLoc() const LLVM_READONLY { return KWLoc; }
+ SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }
+
+ static bool classof(const Stmt *T) {
+ return T->getStmtClass() == BuiltinBitCastExprClass;
+ }
+};
+
} // namespace clang
#endif // LLVM_CLANG_AST_EXPRCXX_H
Index: clang/include/clang-c/Index.h
===================================================================
--- clang/include/clang-c/Index.h
+++ clang/include/clang-c/Index.h
@@ -2536,7 +2536,11 @@
*/
CXCursor_OMPTargetTeamsDistributeSimdDirective = 279,
- CXCursor_LastStmt = CXCursor_OMPTargetTeamsDistributeSimdDirective,
+ /** C++2a std::bit_cast expression.
+ */
+ CXCursor_BuiltinBitCastExpr = 280,
+
+ CXCursor_LastStmt = CXCursor_BuiltinBitCastExpr,
/**
* Cursor that represents the translation unit itself.
_______________________________________________
cfe-commits mailing list
[email protected]
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
