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merged 3 commits into from
Mar 22, 2025
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Parsing and binary writing for custom descriptors #7387

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62856a4
Parsing and binary writing for custom descriptors
tlively Mar 21, 2025
ae5d656
Merge branch 'main' into parse-descriptors
tlively Mar 21, 2025
c79dfec
fix
tlively Mar 21, 2025
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2 changes: 2 additions & 0 deletions scripts/test/fuzzing.py
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Expand Up @@ -109,6 +109,8 @@
'coalesce-locals-exact.wast',
'remove-unused-brs-exact.wast',
'exact.wast',
# TODO: fuzzer support for custom descriptors
'custom-descriptors.wast',
]


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13 changes: 8 additions & 5 deletions src/parser/contexts.h
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Expand Up @@ -982,7 +982,9 @@ struct ParseDeclsCtx : NullTypeParserCtx, NullInstrParserCtx {
void addArrayType(ArrayT) {}
void setOpen() {}
void setShared() {}
Result<> addSubtype(HeapTypeT) { return Ok{}; }
void setDescribes(HeapTypeT) {}
void setDescriptor(HeapTypeT) {}
void setSupertype(HeapTypeT) {}
void finishTypeDef(Name name, Index pos) {
// TODO: type annotations
typeDefs.push_back({name, pos, Index(typeDefs.size()), {}});
Expand Down Expand Up @@ -1157,10 +1159,11 @@ struct ParseTypeDefsCtx : TypeParserCtx<ParseTypeDefsCtx> {

void setShared() { builder[index].setShared(); }

Result<> addSubtype(HeapTypeT super) {
builder[index].subTypeOf(super);
return Ok{};
}
void setDescribes(HeapTypeT desc) { builder[index].describes(desc); }

void setDescriptor(HeapTypeT desc) { builder[index].descriptor(desc); }

void setSupertype(HeapTypeT super) { builder[index].subTypeOf(super); }

void finishTypeDef(Name name, Index pos) { names[index++].name = name; }

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47 changes: 40 additions & 7 deletions src/parser/parsers.h
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Expand Up @@ -357,6 +357,8 @@ Result<typename Ctx::TypeUseT> typeuse(Ctx&, bool allowNames = true);
MaybeResult<ImportNames> inlineImport(Lexer&);
Result<std::vector<Name>> inlineExports(Lexer&);
template<typename Ctx> Result<> comptype(Ctx&);
template<typename Ctx> Result<> describedcomptype(Ctx&);
template<typename Ctx> Result<> describingcomptype(Ctx&);
template<typename Ctx> Result<> sharecomptype(Ctx&);
template<typename Ctx> Result<> subtype(Ctx&);
template<typename Ctx> MaybeResult<> typedef_(Ctx&);
Expand Down Expand Up @@ -2940,19 +2942,50 @@ template<typename Ctx> Result<> comptype(Ctx& ctx) {
return ctx.in.err("expected type description");
}

// sharecomptype ::= '(' 'shared' t:comptype ')' => shared t
// | t:comptype => unshared t
// describedcomptype ::= '(' 'descriptor' typeidx ct:comptype ')'
// | ct:comptype
template<typename Ctx> Result<> describedcomptype(Ctx& ctx) {
if (ctx.in.takeSExprStart("descriptor"sv)) {
auto x = typeidx(ctx);
CHECK_ERR(x);
ctx.setDescriptor(*x);
CHECK_ERR(comptype(ctx));
if (!ctx.in.takeRParen()) {
return ctx.in.err("expected end of described type");
}
return Ok{};
}
return comptype(ctx);
}

// describingcomptype ::= '(' 'describes' typeidx ct:describedcomptype ')'
// | ct: describedcomptype
template<typename Ctx> Result<> describingcomptype(Ctx& ctx) {
if (ctx.in.takeSExprStart("describes"sv)) {
auto x = typeidx(ctx);
CHECK_ERR(x);
ctx.setDescribes(*x);
CHECK_ERR(describedcomptype(ctx));
if (!ctx.in.takeRParen()) {
return ctx.in.err("expected end of describing type");
}
return Ok{};
}
return describedcomptype(ctx);
}

// sharecomptype ::= '(' 'shared' t:describingcomptype ')' => shared t
// | t:describingcomptype => unshared t
template<typename Ctx> Result<> sharecomptype(Ctx& ctx) {
if (ctx.in.takeSExprStart("shared"sv)) {
ctx.setShared();
CHECK_ERR(comptype(ctx));
CHECK_ERR(describingcomptype(ctx));
if (!ctx.in.takeRParen()) {
return ctx.in.err("expected end of shared comptype");
}
} else {
CHECK_ERR(comptype(ctx));
return Ok{};
}
return Ok{};
return describingcomptype(ctx);
}

// subtype ::= '(' 'sub' typeidx? sharecomptype ')' | sharecomptype
Expand All @@ -2963,7 +2996,7 @@ template<typename Ctx> Result<> subtype(Ctx& ctx) {
}
if (auto super = maybeTypeidx(ctx)) {
CHECK_ERR(super);
CHECK_ERR(ctx.addSubtype(*super));
ctx.setSupertype(*super);
}

CHECK_ERR(sharecomptype(ctx));
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6 changes: 4 additions & 2 deletions src/wasm-binary.h
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Expand Up @@ -349,9 +349,11 @@ enum EncodedType {
Array = 0x5e,
Sub = 0x50,
SubFinal = 0x4f,
SharedDef = 0x65,
Shared = -0x1b, // Also 0x65 as an SLEB128
Shared = 0x65,
SharedLEB = -0x1b, // Also 0x65 as an SLEB128
Rec = 0x4e,
Descriptor = 0x4d,
Describes = 0x4c,
// block_type
Empty = -0x40, // 0x40
};
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48 changes: 34 additions & 14 deletions src/wasm/wasm-binary.cpp
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Expand Up @@ -285,7 +285,15 @@ void WasmBinaryWriter::writeTypes() {
}
}
if (type.isShared()) {
o << uint8_t(BinaryConsts::EncodedType::SharedDef);
o << uint8_t(BinaryConsts::EncodedType::Shared);
}
if (auto desc = type.getDescribedType()) {
o << uint8_t(BinaryConsts::EncodedType::Describes);
writeHeapType(*desc);
}
if (auto desc = type.getDescriptorType()) {
o << uint8_t(BinaryConsts::EncodedType::Descriptor);
writeHeapType(*desc);
}
switch (type.getKind()) {
case HeapTypeKind::Func: {
Expand Down Expand Up @@ -1680,7 +1688,7 @@ void WasmBinaryWriter::writeHeapType(HeapType type) {

int ret = 0;
if (type.isShared()) {
o << S32LEB(BinaryConsts::EncodedType::Shared);
o << uint8_t(BinaryConsts::EncodedType::Shared);
}
switch (type.getBasic(Unshared)) {
case HeapType::ext:
Expand Down Expand Up @@ -2206,7 +2214,7 @@ HeapType WasmBinaryReader::getHeapType() {
return types[type];
}
auto share = Unshared;
if (type == BinaryConsts::EncodedType::Shared) {
if (type == BinaryConsts::EncodedType::SharedLEB) {
share = Shared;
type = getS64LEB(); // TODO: Actually s33
}
Expand Down Expand Up @@ -2341,7 +2349,7 @@ void WasmBinaryReader::readTypes() {
auto readHeapType = [&]() -> HeapType {
int64_t htCode = getS64LEB(); // TODO: Actually s33
auto share = Unshared;
if (htCode == BinaryConsts::EncodedType::Shared) {
if (htCode == BinaryConsts::EncodedType::SharedLEB) {
share = Shared;
htCode = getS64LEB(); // TODO: Actually s33
}
Expand Down Expand Up @@ -2467,7 +2475,6 @@ void WasmBinaryReader::readTypes() {
builder.createRecGroup(i, groupSize);
form = getInt8();
}
std::optional<uint32_t> superIndex;
if (form == BinaryConsts::EncodedType::Sub ||
form == BinaryConsts::EncodedType::SubFinal) {
if (form == BinaryConsts::EncodedType::Sub) {
Expand All @@ -2479,14 +2486,34 @@ void WasmBinaryReader::readTypes() {
throwError("Invalid type definition with " + std::to_string(supers) +
" supertypes");
}
superIndex = getU32LEB();
auto superIdx = getU32LEB();
if (superIdx >= builder.size()) {
throwError("invalid supertype index: " + std::to_string(superIdx));
}
builder[i].subTypeOf(builder[superIdx]);
}
form = getInt8();
}
if (form == BinaryConsts::SharedDef) {
if (form == BinaryConsts::EncodedType::Shared) {
builder[i].setShared();
form = getInt8();
}
if (form == BinaryConsts::EncodedType::Describes) {
auto descIdx = getU32LEB();
if (descIdx >= builder.size()) {
throwError("invalid described type index: " + std::to_string(descIdx));
}
builder[i].describes(builder[descIdx]);
form = getInt8();
}
if (form == BinaryConsts::EncodedType::Descriptor) {
auto descIdx = getU32LEB();
if (descIdx >= builder.size()) {
throwError("invalid descriptor type index: " + std::to_string(descIdx));
}
builder[i].descriptor(builder[descIdx]);
form = getInt8();
}
if (form == BinaryConsts::EncodedType::Func) {
builder[i] = readSignatureDef();
} else if (form == BinaryConsts::EncodedType::Cont) {
Expand All @@ -2498,13 +2525,6 @@ void WasmBinaryReader::readTypes() {
} else {
throwError("Bad type form " + std::to_string(form));
}
if (superIndex) {
if (*superIndex > builder.size()) {
throwError("Out of bounds supertype index " +
std::to_string(*superIndex));
}
builder[i].subTypeOf(builder[*superIndex]);
}
}

auto result = builder.build();
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60 changes: 60 additions & 0 deletions test/lit/basic/custom-descriptors.wast
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@@ -0,0 +1,60 @@
;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.

;; RUN: wasm-opt %s -all -o %t.text.wast -g -S
;; RUN: wasm-as %s -all -g -o %t.wasm
;; RUN: wasm-dis %t.wasm -all -o %t.bin.wast
;; RUN: wasm-as %s -all -o %t.nodebug.wasm
;; RUN: wasm-dis %t.nodebug.wasm -all -o %t.bin.nodebug.wast
;; RUN: cat %t.text.wast | filecheck %s --check-prefix=CHECK-TEXT
;; RUN: cat %t.bin.wast | filecheck %s --check-prefix=CHECK-BIN
;; RUN: cat %t.bin.nodebug.wast | filecheck %s --check-prefix=CHECK-BIN-NODEBUG

(module
(rec
;; CHECK-TEXT: (rec
;; CHECK-TEXT-NEXT: (type $described (descriptor $middle (struct)))
;; CHECK-BIN: (rec
;; CHECK-BIN-NEXT: (type $described (descriptor $middle (struct)))
(type $described (descriptor $middle (struct)))
;; CHECK-TEXT: (type $middle (describes $described (descriptor $describing (struct))))
;; CHECK-BIN: (type $middle (describes $described (descriptor $describing (struct))))
(type $middle (describes $described (descriptor $describing (struct))))
;; CHECK-TEXT: (type $describing (describes $middle (struct)))
;; CHECK-BIN: (type $describing (describes $middle (struct)))
(type $describing (describes $middle (struct)))
)

(rec
;; CHECK-TEXT: (rec
;; CHECK-TEXT-NEXT: (type $shared-described (shared (descriptor $shared-describing (struct))))
;; CHECK-BIN: (rec
;; CHECK-BIN-NEXT: (type $shared-described (shared (descriptor $shared-describing (struct))))
(type $shared-described (shared (descriptor $shared-describing (struct))))
;; CHECK-TEXT: (type $shared-describing (shared (describes $shared-described (struct))))
;; CHECK-BIN: (type $shared-describing (shared (describes $shared-described (struct))))
(type $shared-describing (shared (describes $shared-described (struct))))
)


;; CHECK-TEXT: (global $g (ref null $described) (ref.null none))
;; CHECK-BIN: (global $g (ref null $described) (ref.null none))
(global $g (ref null $described) (ref.null none))
;; CHECK-TEXT: (global $shared (ref null $shared-describing) (ref.null (shared none)))
;; CHECK-BIN: (global $shared (ref null $shared-describing) (ref.null (shared none)))
(global $shared (ref null $shared-describing) (ref.null (shared none)))
)
;; CHECK-BIN-NODEBUG: (rec
;; CHECK-BIN-NODEBUG-NEXT: (type $0 (descriptor $1 (struct)))

;; CHECK-BIN-NODEBUG: (type $1 (describes $0 (descriptor $2 (struct))))

;; CHECK-BIN-NODEBUG: (type $2 (describes $1 (struct)))

;; CHECK-BIN-NODEBUG: (rec
;; CHECK-BIN-NODEBUG-NEXT: (type $3 (shared (descriptor $4 (struct))))

;; CHECK-BIN-NODEBUG: (type $4 (shared (describes $3 (struct))))

;; CHECK-BIN-NODEBUG: (global $global$0 (ref null $0) (ref.null none))

;; CHECK-BIN-NODEBUG: (global $global$1 (ref null $4) (ref.null (shared none)))
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