}
return;
}
+
+ // Check if current Field is better as a single field run. When current field
+ // has legal integer width, and its bitfield offset is naturally aligned, it
+ // is better to make the bitfield a separate storage component so as it can be
+ // accessed directly with lower cost.
+ auto IsBetterAsSingleFieldRun = [&](RecordDecl::field_iterator Field) {
+ if (!Types.getCodeGenOpts().FineGrainedBitfieldAccesses)
+ return false;
+ unsigned Width = Field->getBitWidthValue(Context);
+ if (!DataLayout.isLegalInteger(Width))
+ return false;
+ // Make sure Field is natually aligned if it is treated as an IType integer.
+ if (getFieldBitOffset(*Field) %
+ Context.toBits(getAlignment(getIntNType(Width))) !=
+ 0)
+ return false;
+ return true;
+ };
+
+ // The start field is better as a single field run.
+ bool StartFieldAsSingleRun = false;
for (;;) {
// Check to see if we need to start a new run.
if (Run == FieldEnd) {
Run = Field;
StartBitOffset = getFieldBitOffset(*Field);
Tail = StartBitOffset + Field->getBitWidthValue(Context);
+ StartFieldAsSingleRun = IsBetterAsSingleFieldRun(Run);
}
++Field;
continue;
}
- // Add bitfields to the run as long as they qualify.
- if (Field != FieldEnd && Field->getBitWidthValue(Context) != 0 &&
+
+ // If the start field of a new run is better as a single run, or
+ // if current field is better as a single run, or
+ // if current field has zero width bitfield, or
+ // if the offset of current field is inconsistent with the offset of
+ // previous field plus its offset,
+ // skip the block below and go ahead to emit the storage.
+ // Otherwise, try to add bitfields to the run.
+ if (!StartFieldAsSingleRun && Field != FieldEnd &&
+ !IsBetterAsSingleFieldRun(Field) &&
+ Field->getBitWidthValue(Context) != 0 &&
Tail == getFieldBitOffset(*Field)) {
Tail += Field->getBitWidthValue(Context);
++Field;
continue;
}
+
// We've hit a break-point in the run and need to emit a storage field.
llvm::Type *Type = getIntNType(Tail - StartBitOffset);
// Add the storage member to the record and set the bitfield info for all of
Members.push_back(MemberInfo(bitsToCharUnits(StartBitOffset),
MemberInfo::Field, nullptr, *Run));
Run = FieldEnd;
+ StartFieldAsSingleRun = false;
}
}
--- /dev/null
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -ffine-grained-bitfield-accesses \
+// RUN: -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -ffine-grained-bitfield-accesses \
+// RUN: -emit-llvm -fsanitize=address -o - %s | FileCheck %s --check-prefix=SANITIZE
+// Check -fsplit-bitfields will be ignored since sanitizer is enabled.
+
+struct S1 {
+ unsigned f1:2;
+ unsigned f2:6;
+ unsigned f3:8;
+ unsigned f4:4;
+ unsigned f5:8;
+};
+
+S1 a1;
+unsigned read8_1() {
+ // CHECK-LABEL: @_Z7read8_1v
+ // CHECK: %bf.load = load i8, i8* getelementptr inbounds (%struct.S1, %struct.S1* @a1, i32 0, i32 1), align 1
+ // CHECK-NEXT: %bf.cast = zext i8 %bf.load to i32
+ // CHECK-NEXT: ret i32 %bf.cast
+ // SANITIZE-LABEL: @_Z7read8_1v
+ // SANITIZE: %bf.load = load i32, i32* getelementptr inbounds {{.*}}, align 4
+ // SANITIZE: %bf.lshr = lshr i32 %bf.load, 8
+ // SANITIZE: %bf.clear = and i32 %bf.lshr, 255
+ // SANITIZE: ret i32 %bf.clear
+ return a1.f3;
+}
+void write8_1() {
+ // CHECK-LABEL: @_Z8write8_1v
+ // CHECK: store i8 3, i8* getelementptr inbounds (%struct.S1, %struct.S1* @a1, i32 0, i32 1), align 1
+ // CHECK-NEXT: ret void
+ // SANITIZE-LABEL: @_Z8write8_1v
+ // SANITIZE: %bf.load = load i32, i32* getelementptr inbounds {{.*}}, align 4
+ // SANITIZE-NEXT: %bf.clear = and i32 %bf.load, -65281
+ // SANITIZE-NEXT: %bf.set = or i32 %bf.clear, 768
+ // SANITIZE-NEXT: store i32 %bf.set, i32* getelementptr inbounds {{.*}}, align 4
+ // SANITIZE-NEXT: ret void
+ a1.f3 = 3;
+}
+
+unsigned read8_2() {
+ // CHECK-LABEL: @_Z7read8_2v
+ // CHECK: %bf.load = load i16, i16* getelementptr inbounds (%struct.S1, %struct.S1* @a1, i32 0, i32 2), align 2
+ // CHECK-NEXT: %bf.lshr = lshr i16 %bf.load, 4
+ // CHECK-NEXT: %bf.clear = and i16 %bf.lshr, 255
+ // CHECK-NEXT: %bf.cast = zext i16 %bf.clear to i32
+ // CHECK-NEXT: ret i32 %bf.cast
+ // SANITIZE-LABEL: @_Z7read8_2v
+ // SANITIZE: %bf.load = load i32, i32* getelementptr inbounds {{.*}}, align 4
+ // SANITIZE-NEXT: %bf.lshr = lshr i32 %bf.load, 20
+ // SANITIZE-NEXT: %bf.clear = and i32 %bf.lshr, 255
+ // SANITIZE-NEXT: ret i32 %bf.clear
+ return a1.f5;
+}
+void write8_2() {
+ // CHECK-LABEL: @_Z8write8_2v
+ // CHECK: %bf.load = load i16, i16* getelementptr inbounds (%struct.S1, %struct.S1* @a1, i32 0, i32 2), align 2
+ // CHECK-NEXT: %bf.clear = and i16 %bf.load, -4081
+ // CHECK-NEXT: %bf.set = or i16 %bf.clear, 48
+ // CHECK-NEXT: store i16 %bf.set, i16* getelementptr inbounds (%struct.S1, %struct.S1* @a1, i32 0, i32 2), align 2
+ // CHECK-NEXT: ret void
+ // SANITIZE-LABEL: @_Z8write8_2v
+ // SANITIZE: %bf.load = load i32, i32* getelementptr inbounds {{.*}}, align 4
+ // SANITIZE-NEXT: %bf.clear = and i32 %bf.load, -267386881
+ // SANITIZE-NEXT: %bf.set = or i32 %bf.clear, 3145728
+ // SANITIZE-NEXT: store i32 %bf.set, i32* getelementptr inbounds {{.*}}, align 4
+ // SANITIZE-NEXT: ret void
+ a1.f5 = 3;
+}
+
+struct S2 {
+ unsigned long f1:16;
+ unsigned long f2:16;
+ unsigned long f3:6;
+};
+
+S2 a2;
+unsigned read16_1() {
+ // CHECK-LABEL: @_Z8read16_1v
+ // CHECK: %bf.load = load i16, i16* getelementptr inbounds (%struct.S2, %struct.S2* @a2, i32 0, i32 0), align 8
+ // CHECK-NEXT: %bf.cast = zext i16 %bf.load to i64
+ // CHECK-NEXT: %conv = trunc i64 %bf.cast to i32
+ // CHECK-NEXT: ret i32 %conv
+ // SANITIZE-LABEL: @_Z8read16_1v
+ // SANITIZE: %bf.load = load i64, i64* bitcast {{.*}}, align 8
+ // SANITIZE-NEXT: %bf.clear = and i64 %bf.load, 65535
+ // SANITIZE-NEXT: %conv = trunc i64 %bf.clear to i32
+ // SANITIZE-NEXT: ret i32 %conv
+ return a2.f1;
+}
+unsigned read16_2() {
+ // CHECK-LABEL: @_Z8read16_2v
+ // CHECK: %bf.load = load i16, i16* getelementptr inbounds (%struct.S2, %struct.S2* @a2, i32 0, i32 1), align 2
+ // CHECK-NEXT: %bf.cast = zext i16 %bf.load to i64
+ // CHECK-NEXT: %conv = trunc i64 %bf.cast to i32
+ // CHECK-NEXT: ret i32 %conv
+ // SANITIZE-LABEL: @_Z8read16_2v
+ // SANITIZE: %bf.load = load i64, i64* bitcast {{.*}}, align 8
+ // SANITIZE-NEXT: %bf.lshr = lshr i64 %bf.load, 16
+ // SANITIZE-NEXT: %bf.clear = and i64 %bf.lshr, 65535
+ // SANITIZE-NEXT: %conv = trunc i64 %bf.clear to i32
+ // SANITIZE-NEXT: ret i32 %conv
+ return a2.f2;
+}
+
+void write16_1() {
+ // CHECK-LABEL: @_Z9write16_1v
+ // CHECK: store i16 5, i16* getelementptr inbounds (%struct.S2, %struct.S2* @a2, i32 0, i32 0), align 8
+ // CHECK-NEXT: ret void
+ // SANITIZE-LABEL: @_Z9write16_1v
+ // SANITIZE: %bf.load = load i64, i64* bitcast {{.*}}, align 8
+ // SANITIZE-NEXT: %bf.clear = and i64 %bf.load, -65536
+ // SANITIZE-NEXT: %bf.set = or i64 %bf.clear, 5
+ // SANITIZE-NEXT: store i64 %bf.set, i64* bitcast {{.*}}, align 8
+ // SANITIZE-NEXT: ret void
+ a2.f1 = 5;
+}
+void write16_2() {
+ // CHECK-LABEL: @_Z9write16_2v
+ // CHECK: store i16 5, i16* getelementptr inbounds (%struct.S2, %struct.S2* @a2, i32 0, i32 1), align 2
+ // CHECK-NEXT: ret void
+ // SANITIZE-LABEL: @_Z9write16_2v
+ // SANITIZE: %bf.load = load i64, i64* bitcast {{.*}}, align 8
+ // SANITIZE-NEXT: %bf.clear = and i64 %bf.load, -4294901761
+ // SANITIZE-NEXT: %bf.set = or i64 %bf.clear, 327680
+ // SANITIZE-NEXT: store i64 %bf.set, i64* bitcast {{.*}}, align 8
+ // SANITIZE-NEXT: ret void
+ a2.f2 = 5;
+}
+
+struct S3 {
+ unsigned long f1:14;
+ unsigned long f2:18;
+ unsigned long f3:32;
+};
+
+S3 a3;
+unsigned read32_1() {
+ // CHECK-LABEL: @_Z8read32_1v
+ // CHECK: %bf.load = load i32, i32* getelementptr inbounds (%struct.S3, %struct.S3* @a3, i32 0, i32 1), align 4
+ // CHECK-NEXT: %bf.cast = zext i32 %bf.load to i64
+ // CHECK-NEXT: %conv = trunc i64 %bf.cast to i32
+ // CHECK-NEXT: ret i32 %conv
+ // SANITIZE-LABEL: @_Z8read32_1v
+ // SANITIZE: %bf.load = load i64, i64* getelementptr inbounds {{.*}}, align 8
+ // SANITIZE-NEXT: %bf.lshr = lshr i64 %bf.load, 32
+ // SANITIZE-NEXT: %conv = trunc i64 %bf.lshr to i32
+ // SANITIZE-NEXT: ret i32 %conv
+ return a3.f3;
+}
+void write32_1() {
+ // CHECK-LABEL: @_Z9write32_1v
+ // CHECK: store i32 5, i32* getelementptr inbounds (%struct.S3, %struct.S3* @a3, i32 0, i32 1), align 4
+ // CHECK-NEXT: ret void
+ // SANITIZE-LABEL: @_Z9write32_1v
+ // SANITIZE: %bf.load = load i64, i64* getelementptr inbounds {{.*}}, align 8
+ // SANITIZE-NEXT: %bf.clear = and i64 %bf.load, 4294967295
+ // SANITIZE-NEXT: %bf.set = or i64 %bf.clear, 21474836480
+ // SANITIZE-NEXT: store i64 %bf.set, i64* getelementptr inbounds {{.*}}, align 8
+ // SANITIZE-NEXT: ret void
+ a3.f3 = 5;
+}
projects / clang / commitdiff