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Differential D109560

BPF: change BTF_KIND_TAG format
ClosedPublic

Authored by yonghong-song on Sep 9 2021, 6:41 PM.

Details

Reviewers
ast
anakryiko
Commits
rGe52617c31de1: BPF: change BTF_KIND_TAG format
Summary

Previously we have the following binary representation:

struct bpf_type { name, info, type }
struct btf_tag { __u32 component_idx; }

If the tag points to a struct/union/var/func type, we will have

kflag = 1, component_idx = 0

if the tag points to struct/union member or func argument, we will have

kflag = 0, component_idx = 0, ..., vlen - 1

The above rather makes interface complex to have both kflag and
component needed to determine its legality and index.

This patch simplifies the interface by removing kflag involvement.

component_idx = (u32)-1 : tag pointing to a type
component_idx = 0 ... vlen - 1 : tag pointing to a member or argument

and kflag is always 0 and there is no need to check.

Diff Detail

Event Timeline

yonghong-song created this revision.Sep 9 2021, 6:41 PM
Herald added a subscriber: hiraditya. · View Herald TranscriptSep 9 2021, 6:41 PM
yonghong-song requested review of this revision.Sep 9 2021, 6:41 PM
Herald added a project: Restricted Project. · View Herald TranscriptSep 9 2021, 6:41 PM
Herald added a subscriber: llvm-commits. · View Herald Transcript
anakryiko accepted this revision.Sep 9 2021, 6:42 PM
This revision is now accepted and ready to land.Sep 9 2021, 6:42 PM
This revision was landed with ongoing or failed builds.Sep 9 2021, 7:05 PM
Closed by commit rGe52617c31de1: BPF: change BTF_KIND_TAG format (authored by yonghong-song). · Explain Why
This revision was automatically updated to reflect the committed changes.
yonghong-song added a commit: rGe52617c31de1: BPF: change BTF_KIND_TAG format.
Harbormaster completed remote builds in B123343: Diff 371763.Sep 9 2021, 7:16 PM

Revision Contents

PathSize
llvm/
lib/
Target/
BPF/
10 lines
test/
CodeGen/
BPF/
BTF/
16 lines
11 lines

Diff 371763

llvm/lib/Target/BPF/BTFDebug.cpp

Show First 20 Lines • Show All 380 Lines • ▼ Show 20 Lines
void BTFTypeFloat::completeType(BTFDebug &BDebug) { void BTFTypeFloat::completeType(BTFDebug &BDebug) {
if (IsCompleted) if (IsCompleted)
return; return;
IsCompleted = true; IsCompleted = true;
BTFType.NameOff = BDebug.addString(Name); BTFType.NameOff = BDebug.addString(Name);
} }
BTFTypeTag::BTFTypeTag(uint32_t BaseTypeId, int ComponentId, StringRef Tag) BTFTypeTag::BTFTypeTag(uint32_t BaseTypeId, int ComponentIdx, StringRef Tag)
: Tag(Tag) { : Tag(Tag) {
Kind = BTF::BTF_KIND_TAG; Kind = BTF::BTF_KIND_TAG;
BTFType.Info = ((ComponentId < 0) << 31) | (Kind << 24); BTFType.Info = Kind << 24;
BTFType.Type = BaseTypeId; BTFType.Type = BaseTypeId;
Info = ComponentId < 0 ? 0 : ComponentId; Info = ComponentIdx;
} }
void BTFTypeTag::completeType(BTFDebug &BDebug) { void BTFTypeTag::completeType(BTFDebug &BDebug) {
if (IsCompleted) if (IsCompleted)
return; return;
IsCompleted = true; IsCompleted = true;
BTFType.NameOff = BDebug.addString(Tag); BTFType.NameOff = BDebug.addString(Tag);
▲ Show 20 Lines • Show All 89 Lines • ▼ Show 20 Linesvoid BTFDebug::visitSubroutineType(
// Visit return type and func arg types. // Visit return type and func arg types.
for (const auto Element : Elements) { for (const auto Element : Elements) {
visitTypeEntry(Element); visitTypeEntry(Element);
} }
} }
void BTFDebug::processAnnotations(DINodeArray Annotations, uint32_t BaseTypeId, void BTFDebug::processAnnotations(DINodeArray Annotations, uint32_t BaseTypeId,
int ComponentId) { int ComponentIdx) {
if (!Annotations) if (!Annotations)
return; return;
for (const Metadata *Annotation : Annotations->operands()) { for (const Metadata *Annotation : Annotations->operands()) {
const MDNode *MD = cast<MDNode>(Annotation); const MDNode *MD = cast<MDNode>(Annotation);
const MDString *Name = cast<MDString>(MD->getOperand(0)); const MDString *Name = cast<MDString>(MD->getOperand(0));
if (!Name->getString().equals("btf_tag")) if (!Name->getString().equals("btf_tag"))
continue; continue;
const MDString *Value = cast<MDString>(MD->getOperand(1)); const MDString *Value = cast<MDString>(MD->getOperand(1));
auto TypeEntry = std::make_unique<BTFTypeTag>(BaseTypeId, ComponentId, auto TypeEntry = std::make_unique<BTFTypeTag>(BaseTypeId, ComponentIdx,
Value->getString()); Value->getString());
addType(std::move(TypeEntry)); addType(std::move(TypeEntry));
} }
} }
/// Handle structure/union types. /// Handle structure/union types.
void BTFDebug::visitStructType(const DICompositeType *CTy, bool IsStruct, void BTFDebug::visitStructType(const DICompositeType *CTy, bool IsStruct,
uint32_t &TypeId) { uint32_t &TypeId) {
▲ Show 20 Lines • Show All 913 Lines • Show Last 20 Lines

llvm/test/CodeGen/BPF/BTF/tag-1.ll

Show First 20 Lines • Show All 44 Lines • ▼ Show 20 Lines
; CHECK-NEXT: .long 8 ; CHECK-NEXT: .long 8
; CHECK-NEXT: .long 4 ; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 4 ; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 0 # 0x0 ; CHECK-NEXT: .long 0 # 0x0
; CHECK-NEXT: .long 7 ; CHECK-NEXT: .long 7
; CHECK-NEXT: .long 4 ; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 32 # 0x20 ; CHECK-NEXT: .long 32 # 0x20
; CHECK-NEXT: .long 10 # BTF_KIND_TAG(id = 2) ; CHECK-NEXT: .long 10 # BTF_KIND_TAG(id = 2)
; CHECK-NEXT: .long 2432696320 # 0x91000000 ; CHECK-NEXT: .long 285212672 # 0x11000000
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 0 ; CHECK-NEXT: .long 4294967295
; CHECK-NEXT: .long 15 # BTF_KIND_TAG(id = 3) ; CHECK-NEXT: .long 15 # BTF_KIND_TAG(id = 3)
; CHECK-NEXT: .long 2432696320 # 0x91000000 ; CHECK-NEXT: .long 285212672 # 0x11000000
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 0 ; CHECK-NEXT: .long 4294967295
; CHECK-NEXT: .long 20 # BTF_KIND_INT(id = 4) ; CHECK-NEXT: .long 20 # BTF_KIND_INT(id = 4)
; CHECK-NEXT: .long 16777216 # 0x1000000 ; CHECK-NEXT: .long 16777216 # 0x1000000
; CHECK-NEXT: .long 4 ; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 16777248 # 0x1000020 ; CHECK-NEXT: .long 16777248 # 0x1000020
; CHECK-NEXT: .long 10 # BTF_KIND_TAG(id = 5) ; CHECK-NEXT: .long 10 # BTF_KIND_TAG(id = 5)
; CHECK-NEXT: .long 285212672 # 0x11000000 ; CHECK-NEXT: .long 285212672 # 0x11000000
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 15 # BTF_KIND_TAG(id = 6) ; CHECK-NEXT: .long 15 # BTF_KIND_TAG(id = 6)
; CHECK-NEXT: .long 285212672 # 0x11000000 ; CHECK-NEXT: .long 285212672 # 0x11000000
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 24 # BTF_KIND_VAR(id = 7) ; CHECK-NEXT: .long 24 # BTF_KIND_VAR(id = 7)
; CHECK-NEXT: .long 234881024 # 0xe000000 ; CHECK-NEXT: .long 234881024 # 0xe000000
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 10 # BTF_KIND_TAG(id = 8) ; CHECK-NEXT: .long 10 # BTF_KIND_TAG(id = 8)
; CHECK-NEXT: .long 2432696320 # 0x91000000 ; CHECK-NEXT: .long 285212672 # 0x11000000
; CHECK-NEXT: .long 7 ; CHECK-NEXT: .long 7
; CHECK-NEXT: .long 0 ; CHECK-NEXT: .long 4294967295
; CHECK-NEXT: .long 15 # BTF_KIND_TAG(id = 9) ; CHECK-NEXT: .long 15 # BTF_KIND_TAG(id = 9)
; CHECK-NEXT: .long 2432696320 # 0x91000000 ; CHECK-NEXT: .long 285212672 # 0x11000000
; CHECK-NEXT: .long 7 ; CHECK-NEXT: .long 7
; CHECK-NEXT: .long 0 ; CHECK-NEXT: .long 4294967295
; CHECK: .ascii "t1" # string offset=1 ; CHECK: .ascii "t1" # string offset=1
; CHECK: .ascii "a1" # string offset=4 ; CHECK: .ascii "a1" # string offset=4
; CHECK: .ascii "a2" # string offset=7 ; CHECK: .ascii "a2" # string offset=7
; CHECK: .ascii "tag1" # string offset=10 ; CHECK: .ascii "tag1" # string offset=10
; CHECK: .ascii "tag2" # string offset=15 ; CHECK: .ascii "tag2" # string offset=15
; CHECK: .ascii "int" # string offset=20 ; CHECK: .ascii "int" # string offset=20
; CHECK: .ascii "g1" # string offset=24 ; CHECK: .ascii "g1" # string offset=24

llvm/test/CodeGen/BPF/BTF/tag-2.ll

Show First 20 Lines • Show All 89 Lines • ▼ Show 20 Lines
; CHECK-NEXT: .long 15 # BTF_KIND_FUNC(id = 4) ; CHECK-NEXT: .long 15 # BTF_KIND_FUNC(id = 4)
; CHECK-NEXT: .long 201326593 # 0xc000001 ; CHECK-NEXT: .long 201326593 # 0xc000001
; CHECK-NEXT: .long 3 ; CHECK-NEXT: .long 3
; CHECK-NEXT: .long 19 # BTF_KIND_TAG(id = 5) ; CHECK-NEXT: .long 19 # BTF_KIND_TAG(id = 5)
; CHECK-NEXT: .long 285212672 # 0x11000000 ; CHECK-NEXT: .long 285212672 # 0x11000000
; CHECK-NEXT: .long 4 ; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 19 # BTF_KIND_TAG(id = 6) ; CHECK-NEXT: .long 19 # BTF_KIND_TAG(id = 6)
; CHECK-NEXT: .long 2432696320 # 0x91000000 ; CHECK-NEXT: .long 285212672 # 0x11000000
; CHECK-NEXT: .long 4 ; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 0 ; CHECK-NEXT: .long 4294967295
; CHECK-NEXT: .long 0 # BTF_KIND_FUNC_PROTO(id = 7) ; CHECK-NEXT: .long 0 # BTF_KIND_FUNC_PROTO(id = 7)
; CHECK-NEXT: .long 218103810 # 0xd000002 ; CHECK-NEXT: .long 218103810 # 0xd000002
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 0 ; CHECK-NEXT: .long 0
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 0 ; CHECK-NEXT: .long 0
; CHECK-NEXT: .long 1 ; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 72 # BTF_KIND_FUNC(id = 8) ; CHECK-NEXT: .long 72 # BTF_KIND_FUNC(id = 8)
; CHECK-NEXT: .long 201326594 # 0xc000002 ; CHECK-NEXT: .long 201326594 # 0xc000002
; CHECK-NEXT: .long 7 ; CHECK-NEXT: .long 7
; CHECK-NEXT: .long 19 # BTF_KIND_TAG(id = 9) ; CHECK-NEXT: .long 19 # BTF_KIND_TAG(id = 9)
; CHECK-NEXT: .long 2432696320 # 0x91000000 ; CHECK-NEXT: .long 285212672 # 0x11000000
; CHECK-NEXT: .long 8 ; CHECK-NEXT: .long 8
; CHECK-NEXT: .long 0 ; CHECK-NEXT: .long 4294967295
; CHECK-NEXT: .long 76 # BTF_KIND_TAG(id = 10) ; CHECK-NEXT: .long 76 # BTF_KIND_TAG(id = 10)
; CHECK-NEXT: .long 2432696320 # 0x91000000 ; CHECK-NEXT: .long 285212672 # 0x11000000
; CHECK-NEXT: .long 8 ; CHECK-NEXT: .long 8
; CHECK-NEXT: .long 4294967295
; CHECK: .ascii "int" # string offset=1 ; CHECK: .ascii "int" # string offset=1
; CHECK: .ascii "arg1" # string offset=5 ; CHECK: .ascii "arg1" # string offset=5
; CHECK: .ascii "arg2" # string offset=10 ; CHECK: .ascii "arg2" # string offset=10
; CHECK: .ascii "foo" # string offset=15 ; CHECK: .ascii "foo" # string offset=15
; CHECK: .ascii "tag1" # string offset=19 ; CHECK: .ascii "tag1" # string offset=19
; CHECK: .ascii "bar" # string offset=72 ; CHECK: .ascii "bar" # string offset=72
; CHECK: .ascii "tag2" # string offset=76 ; CHECK: .ascii "tag2" # string offset=76