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[Draft] - Align key components to the nearest 8-bit size #30

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[Draft] - Align key components to the nearest 8-bit size #30

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236 changes: 191 additions & 45 deletions backends/ebpf/codeGen.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -351,7 +351,10 @@ void CodeGenInspector::emitAssignStatement(const IR::Type *ltype, const IR::Expr
width = scalar->implementationWidthInBits();
memcpy = !EBPFScalarType::generatesScalar(width);
}

if (builder->target->name == "P4TC") {
emitTCAssignmentEndianessConversion(lexpr, rexpr, lpath, memcpy, scalar->bytesRequired());
return;
}
builder->emitIndent();
if (memcpy) {
builder->append("__builtin_memcpy(&");
Expand All @@ -373,11 +376,7 @@ void CodeGenInspector::emitAssignStatement(const IR::Type *ltype, const IR::Expr
builder->append(lpath);
}
builder->append(" = ");
if (builder->target->name == "P4TC") {
emitTCAssignmentEndianessConversion(lexpr, rexpr);
} else {
visit(rexpr);
}
visit(rexpr);
}
builder->endOfStatement();
}
Expand Down Expand Up @@ -492,7 +491,9 @@ void CodeGenInspector::emitAndConvertByteOrder(const IR::Expression *expr, cstri
}
unsigned shift = loadSize - widthToEmit;
builder->appendFormat("%s(", emit);
visit(expr);
bool primitive = isPrimitive(expr);
if (primitive) { visit(expr);
} else { getBitAlignment(expr); }
if (shift != 0 && byte_order == "HOST") builder->appendFormat(" << %d", shift);
builder->append(")");
}
Expand All @@ -512,7 +513,9 @@ void CodeGenInspector::emitTCBinaryOperation(const IR::Operation_Binary *b, bool
rByteOrder = tcTarget->getByteOrder(typeMap, action, rexpr);
}
if (lByteOrder == rByteOrder) {
visit(lexpr);
bool primitive = isPrimitive(lexpr);
if (primitive) { visit(lexpr);
} else { getBitAlignment(lexpr); }
if (isScalar) {
builder->spc();
builder->append(stringop);
Expand All @@ -521,7 +524,9 @@ void CodeGenInspector::emitTCBinaryOperation(const IR::Operation_Binary *b, bool
builder->append(", &");
}
if (!b->is<IR::Operation_Relation>()) expressionPrecedence = b->getPrecedence() + 1;
visit(rexpr);
primitive = isPrimitive(rexpr);
if (primitive) { visit(rexpr);
} else { getBitAlignment(rexpr); }
return;
}
if (lByteOrder == "NETWORK") {
Expand All @@ -542,14 +547,18 @@ void CodeGenInspector::emitTCBinaryOperation(const IR::Operation_Binary *b, bool
builder->append(", &");
}
if (!b->is<IR::Operation_Relation>()) expressionPrecedence = b->getPrecedence() + 1;
visit(rexpr);
bool primitive = isPrimitive(rexpr);
if (primitive) { visit(rexpr);
} else { getBitAlignment(rexpr); }
return;
} else if (rByteOrder == "NETWORK") {
// ConvertRight
auto ftype = typeMap->getType(rexpr);
auto et = EBPFTypeFactory::instance->create(ftype);
unsigned width = dynamic_cast<IHasWidth *>(et)->widthInBits();
visit(lexpr);
bool primitive = isPrimitive(lexpr);
if (primitive) { visit(lexpr);
} else { getBitAlignment(lexpr); }
if (isScalar) {
builder->spc();
builder->append(stringop);
Expand All @@ -568,46 +577,183 @@ void CodeGenInspector::emitTCBinaryOperation(const IR::Operation_Binary *b, bool
}

void CodeGenInspector::emitTCAssignmentEndianessConversion(const IR::Expression *lexpr,
const IR::Expression *rexpr) {
auto action = findContext<IR::P4Action>();
auto b = dynamic_cast<const P4TCTarget *>(builder->target);
cstring lByteOrder = "HOST"_cs, rByteOrder = "HOST"_cs;
if (lexpr) {
lByteOrder = b->getByteOrder(typeMap, action, lexpr);
const IR::Expression *rexpr,
cstring lpath, bool memcpy,
unsigned width) {
builder->emitIndent();
if (memcpy) {
builder->append("__builtin_memcpy(&");
if (lexpr != nullptr) {
visit(lexpr);
} else {
builder->append(lpath);
}
builder->append(", &");
if (rexpr->is<IR::Constant>()) {
builder->appendFormat("(u8[%u])", width);
}
visit(rexpr);
builder->appendFormat(", %d)", width);
} else {
if (lexpr != nullptr) {
bool primitive = isPrimitive(lexpr);
if (primitive) {
visit(lexpr);
} else {
storeBitAlignment(lexpr, rexpr);
return;
}
} else {
builder->append(lpath);
}
builder->append(" = ");
auto action = findContext<IR::P4Action>();
auto b = dynamic_cast<const P4TCTarget *>(builder->target);
cstring lByteOrder = "HOST"_cs, rByteOrder = "HOST"_cs;
if (lexpr) {
lByteOrder = b->getByteOrder(typeMap, action, lexpr);
}
if (rexpr) {
rByteOrder = b->getByteOrder(typeMap, action, rexpr);
}
auto ftype = typeMap->getType(rexpr);
auto et = EBPFTypeFactory::instance->create(ftype);
unsigned width = dynamic_cast<IHasWidth *>(et)->widthInBits();
// TODO:
if (lByteOrder == rByteOrder) {
bool primitive = isPrimitive(rexpr);
if (primitive) { visit(rexpr);
} else { getBitAlignment(rexpr); }
return;
}
if (width <= 8) {
visit(rexpr);
return;
}
if (rByteOrder == "NETWORK") {
// If left side of assignment is not annotated field i.e host endian and right expression
// is annotated field i.e network endian, we need to convert rexp to host order.
// Example -
// select_0 = hdr.ipv4.diffserv
// select_0 = bntoh(hdr.ipv4.diffserv)
//
emitAndConvertByteOrder(rexpr, "HOST"_cs);
}
if (lByteOrder == "NETWORK") {
// If left side of assignment is annotated field i.e network endian, we need to convert
// right expression to network order.
// Example -
// hdr.opv4.diffserv = 0x1;
// hdr.opv4.diffserv = bhton(0x1)
//
emitAndConvertByteOrder(rexpr, "NETWORK"_cs);
}
}
if (rexpr) {
rByteOrder = b->getByteOrder(typeMap, action, rexpr);
builder->endOfStatement();
return;
}

bool CodeGenInspector::isPrimitive(const IR::Expression* expression) {
if (!expression->is<IR::Member>()) { return true; }
auto ftype = typeMap->getType(expression);
if (!ftype) { return true; }
auto tcTarget = dynamic_cast<const P4TCTarget *>(builder->target);
auto ebpfType = EBPFTypeFactory::instance->create(ftype);
EBPFScalarType *scalar = nullptr;
if (ebpfType->is<EBPFScalarType>()) {
scalar = ebpfType->to<EBPFScalarType>();
bool isPrimitive = tcTarget->isPrimitiveByteAligned(scalar->implementationWidthInBits());
if (!isPrimitive) {
return false;
}
}
if (lByteOrder == rByteOrder) {
visit(rexpr);
return true;
}

void CodeGenInspector::getBitAlignment(const IR::Expression* expression) {
auto ftype = typeMap->getType(expression);
if (!ftype) { return; }
auto ebpfType = EBPFTypeFactory::instance->create(ftype);
EBPFScalarType *scalar = nullptr;
if (ebpfType->is<EBPFScalarType>()) {
scalar = ebpfType->to<EBPFScalarType>();
if (scalar->implementationWidthInBits() < 32) {
builder->append("getPrimitive32(");
visit(expression);
builder->append(", ");
} else {
builder->append("getPrimitive64(");
visit(expression);
builder->appendFormat(", %d", scalar->implementationWidthInBits());
}
builder->append(")");
return;
}
auto ftype = typeMap->getType(rexpr);
auto et = EBPFTypeFactory::instance->create(ftype);
unsigned width = dynamic_cast<IHasWidth *>(et)->widthInBits();
if (width <= 8) {
visit(rexpr);
return;
}

void CodeGenInspector::storeBitAlignment(const IR::Expression* lexpr, const IR::Expression* rexpr) {
auto tcTarget = dynamic_cast<const P4TCTarget *>(builder->target);
auto ftype = typeMap->getType(lexpr);
if (!ftype) { return;}
auto ebpfType = EBPFTypeFactory::instance->create(ftype);
EBPFScalarType *scalar = nullptr;
if (ebpfType->is<EBPFScalarType>()) {
scalar = ebpfType->to<EBPFScalarType>();
if (scalar->implementationWidthInBits() < 32) {
builder->append("storePrimitive32(&");
visit(lexpr);
builder->append(", ");
} else {
builder->append("storePrimitive64(&");
visit(lexpr);
builder->appendFormat(", %d, (" , scalar->implementationWidthInBits());
}
auto action = findContext<IR::P4Action>();
cstring lByteOrder = "HOST"_cs, rByteOrder = "HOST"_cs;
if (lexpr) {
lByteOrder = tcTarget->getByteOrder(typeMap, action, lexpr);
}
if (rexpr) {
rByteOrder = tcTarget->getByteOrder(typeMap, action, rexpr);
}
auto ftype = typeMap->getType(rexpr);
auto et = EBPFTypeFactory::instance->create(ftype);
unsigned width = dynamic_cast<IHasWidth *>(et)->widthInBits();
// TODO:
if (lByteOrder == rByteOrder) {
bool primitive = isPrimitive(rexpr);
if (primitive) { visit(rexpr);
} else { getBitAlignment(rexpr); }
builder->append("));");
return;
}
if (width <= 8) {
visit(rexpr);
builder->append("));");
return;
}
if (rByteOrder == "NETWORK") {
// If left side of assignment is not annotated field i.e host endian and right expression
// is annotated field i.e network endian, we need to convert rexp to host order.
// Example -
// select_0 = hdr.ipv4.diffserv
// select_0 = bntoh(hdr.ipv4.diffserv)
//
emitAndConvertByteOrder(rexpr, "HOST"_cs);
}
if (lByteOrder == "NETWORK") {
// If left side of assignment is annotated field i.e network endian, we need to convert
// right expression to network order.
// Example -
// hdr.opv4.diffserv = 0x1;
// hdr.opv4.diffserv = bhton(0x1)
//
emitAndConvertByteOrder(rexpr, "NETWORK"_cs);
}
builder->append("));");
return;
}
if (rByteOrder == "NETWORK") {
// If left side of assignment is not annotated field i.e host endian and right expression
// is annotated field i.e network endian, we need to convert rexp to host order.
// Example -
// select_0 = hdr.ipv4.diffserv
// select_0 = bntoh(hdr.ipv4.diffserv)
//
emitAndConvertByteOrder(rexpr, "HOST"_cs);
}
if (lByteOrder == "NETWORK") {
// If left side of assignment is annotated field i.e network endian, we need to convert
// right expression to network order.
// Example -
// hdr.opv4.diffserv = 0x1;
// hdr.opv4.diffserv = bhton(0x1)
//
emitAndConvertByteOrder(rexpr, "NETWORK"_cs);
}

return;
}

Expand Down
6 changes: 5 additions & 1 deletion backends/ebpf/codeGen.h
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Original file line number Diff line number Diff line change
Expand Up @@ -129,7 +129,11 @@ class CodeGenInspector : public Inspector {
void emitAndConvertByteOrder(const IR::Expression *expr, cstring byte_order);
void emitTCBinaryOperation(const IR::Operation_Binary *b, bool isScalar);
void emitTCAssignmentEndianessConversion(const IR::Expression *lexpr,
const IR::Expression *rexpr);
const IR::Expression *rexpr,
cstring lpath, bool memcpy, unsigned width);
void getBitAlignment(const IR::Expression* expression);
bool isPrimitive(const IR::Expression* expression);
void storeBitAlignment(const IR::Expression* lexpr, const IR::Expression* rexpr);
};

class EBPFInitializerUtils {
Expand Down
2 changes: 1 addition & 1 deletion backends/ebpf/ebpfBackend.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@ void emitFilterModel(const EbpfOptions &options, Target *target, const IR::Tople
CodeBuilder c(target);
CodeBuilder h(target);

EBPFTypeFactory::createFactory(typeMap);
EBPFTypeFactory::createFactory(typeMap, false);
auto ebpfprog = new EBPFProgram(options, toplevel->getProgram(), refMap, typeMap, toplevel);
if (!ebpfprog->build()) return;

Expand Down
62 changes: 61 additions & 1 deletion backends/ebpf/ebpfType.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ limitations under the License.
namespace P4::EBPF {

EBPFTypeFactory *EBPFTypeFactory::instance;
bool EBPFTypeFactory::isTC;

EBPFType *EBPFTypeFactory::create(const IR::Type *type) {
CHECK_NULL(type);
Expand All @@ -27,7 +28,11 @@ EBPFType *EBPFTypeFactory::create(const IR::Type *type) {
if (type->is<IR::Type_Boolean>()) {
result = new EBPFBoolType();
} else if (auto bt = type->to<IR::Type_Bits>()) {
result = new EBPFScalarType(bt);
if (EBPFTypeFactory::isTC) {
result = new EBPFScalarTypePNA(bt);
} else {
result = new EBPFScalarType(bt);
}
} else if (auto st = type->to<IR::Type_StructLike>()) {
result = new EBPFStructType(st);
} else if (auto tt = type->to<IR::Type_Typedef>()) {
Expand Down Expand Up @@ -384,4 +389,59 @@ void EBPFMethodDeclaration::emit(CodeBuilder *builder) {
builder->newline();
}

unsigned EBPFScalarTypePNA::alignment() const {
if (width <= 8)
return 1;
else if (width <= 16)
return 2;
else if (width <= 24)
return 1; // compiled as u8*
else if (width <= 32)
return 4;
else if (width <= 56)
return 1; // compiled as u8*
else if (width <= 64)
return 8;
else
// compiled as u8*
return 1;
}

void EBPFScalarTypePNA::declare(CodeBuilder *builder, cstring id, bool asPointer) {
if (generatesScalar(width) && isPrimitiveByteAligned == true) {
emit(builder);
if (asPointer) builder->append("*");
builder->spc();
builder->append(id);
} else {
if (asPointer)
builder->appendFormat("u8* %s", id.c_str());
else
builder->appendFormat("u8 %s[%d]", id.c_str(), bytesRequired());
}
}

void EBPFScalarTypePNA::declareInit(CodeBuilder *builder, cstring id, bool asPointer) {
if (generatesScalar(width) && isPrimitiveByteAligned == true ) {
emit(builder);
if (asPointer) builder->append("*");
builder->spc();
id = id + cstring(" = 0");
builder->append(id);
} else {
if (asPointer)
builder->appendFormat("u8* %s = NULL", id.c_str());
else
builder->appendFormat("u8 %s[%d] = {0}", id.c_str(), bytesRequired());
}
}

void EBPFScalarTypePNA::emitInitializer(CodeBuilder *builder) {
if (generatesScalar(width) && isPrimitiveByteAligned == true) {
builder->append("0");
} else {
builder->append("{ 0 }");
}
}

} // namespace P4::EBPF
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