sbc100 created this revision.
Herald added subscribers: cfe-commits, sunfish, aheejin, hiraditya,
jgravelle-google, dschuff.
Herald added a project: clang.
sbc100 added reviewers: sunfish, kripken.
This matches the existing export-name attribute but exports that symbol
but its llvm symbol name. This corresponds directly to the existing
WASM_SYMBOL_EXPORTED symbol flag.
This allows the existing emscripgten macro `EMSCERIPTEN_KEEPALIVE` to be
implemented in terms of this attribute rather then the current
workaround which uses the `used` attribute.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D76547
Files:
clang/include/clang/Basic/Attr.td
clang/include/clang/Basic/AttrDocs.td
clang/lib/CodeGen/TargetInfo.cpp
clang/lib/Sema/SemaDeclAttr.cpp
clang/test/CodeGen/wasm-export.c
llvm/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp
llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.cpp
llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.h
llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
llvm/test/CodeGen/WebAssembly/export.ll
Index: llvm/test/CodeGen/WebAssembly/export.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/WebAssembly/export.ll
@@ -0,0 +1,17 @@
+; RUN: llc < %s -asm-verbose=false -wasm-keep-registers | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+define void @test() #0 {
+ ret void
+}
+
+declare void @test2() #1
+
+
+attributes #0 = { "wasm-exported" }
+attributes #1 = { "wasm-exported" }
+
+; CHECK: .export test
+; CHECK: .export test2
Index: llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
===================================================================
--- llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
+++ llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
@@ -134,6 +134,12 @@
}
}
+ if (F.hasFnAttribute("wasm-exported")) {
+ auto *Sym = cast<MCSymbolWasm>(getSymbol(&F));
+ Sym->setExported();
+ getTargetStreamer()->emitExport(Sym);
+ }
+
if (F.hasFnAttribute("wasm-export-name")) {
auto *Sym = cast<MCSymbolWasm>(getSymbol(&F));
StringRef Name = F.getFnAttribute("wasm-export-name").getValueAsString();
Index: llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.h
===================================================================
--- llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.h
+++ llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.h
@@ -51,6 +51,8 @@
/// .export_name
virtual void emitExportName(const MCSymbolWasm *Sym,
StringRef ExportName) = 0;
+ /// .export
+ virtual void emitExport(const MCSymbolWasm *Sym) = 0;
protected:
void emitValueType(wasm::ValType Type);
@@ -72,6 +74,7 @@
void emitImportModule(const MCSymbolWasm *Sym, StringRef ImportModule) override;
void emitImportName(const MCSymbolWasm *Sym, StringRef ImportName) override;
void emitExportName(const MCSymbolWasm *Sym, StringRef ExportName) override;
+ void emitExport(const MCSymbolWasm *Sym) override;
};
/// This part is for Wasm object output
@@ -91,6 +94,7 @@
StringRef ImportName) override {}
void emitExportName(const MCSymbolWasm *Sym,
StringRef ExportName) override {}
+ void emitExport(const MCSymbolWasm *Sym) override {}
};
/// This part is for null output
@@ -108,6 +112,7 @@
void emitImportModule(const MCSymbolWasm *, StringRef) override {}
void emitImportName(const MCSymbolWasm *, StringRef) override {}
void emitExportName(const MCSymbolWasm *, StringRef) override {}
+ void emitExport(const MCSymbolWasm *) override {}
};
} // end namespace llvm
Index: llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.cpp
===================================================================
--- llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.cpp
+++ llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.cpp
@@ -100,6 +100,10 @@
<< ExportName << '\n';
}
+void WebAssemblyTargetAsmStreamer::emitExport(const MCSymbolWasm *Sym) {
+ OS << "\t.export\t" << Sym->getName() << '\n';
+}
+
void WebAssemblyTargetAsmStreamer::emitIndIdx(const MCExpr *Value) {
OS << "\t.indidx \t" << *Value << '\n';
}
Index: llvm/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp
===================================================================
--- llvm/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp
+++ llvm/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp
@@ -717,6 +717,15 @@
return expect(AsmToken::EndOfStatement, "EOL");
}
+ if (DirectiveID.getString() == ".export") {
+ auto SymName = expectIdent();
+ if (SymName.empty())
+ return true;
+ auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
+ WasmSym->setExported();
+ TOut.emitExport(WasmSym);
+ }
+
if (DirectiveID.getString() == ".export_name") {
auto SymName = expectIdent();
if (SymName.empty())
Index: clang/test/CodeGen/wasm-export.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/wasm-export.c
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -triple wasm32-unknown-unknown-wasm -emit-llvm -o - %s | FileCheck %s
+
+int __attribute__((exported)) foo(void);
+
+int foo(void) {
+ return 43;
+}
+
+// CHECK: @llvm.used = appending global [1 x i8*] [i8* bitcast (i32 ()* @foo to i8*)]
+
+// CHECK: define i32 @foo() [[A:#[0-9]+]]
+
+// CHECK: attributes [[A]] = {{{.*}} "wasm-export" {{.*}}}
Index: clang/lib/Sema/SemaDeclAttr.cpp
===================================================================
--- clang/lib/Sema/SemaDeclAttr.cpp
+++ clang/lib/Sema/SemaDeclAttr.cpp
@@ -5845,6 +5845,23 @@
D->addAttr(UsedAttr::CreateImplicit(S.Context));
}
+static void handleWebAssemblyExportedAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+ if (!isFunctionOrMethod(D)) {
+ S.Diag(D->getLocation(), diag::warn_attribute_wrong_decl_type)
+ << "'exported'" << ExpectedFunction;
+ return;
+ }
+
+ auto *FD = cast<FunctionDecl>(D);
+ if (FD->isThisDeclarationADefinition()) {
+ S.Diag(D->getLocation(), diag::err_alias_is_definition) << FD << 0;
+ return;
+ }
+
+ D->addAttr(::new (S.Context) WebAssemblyExportedAttr(S.Context, AL));
+ D->addAttr(UsedAttr::CreateImplicit(S.Context));
+}
+
static void handleWebAssemblyImportModuleAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
if (!isFunctionOrMethod(D)) {
S.Diag(D->getLocation(), diag::warn_attribute_wrong_decl_type)
@@ -6807,6 +6824,9 @@
case ParsedAttr::AT_WebAssemblyExportName:
handleWebAssemblyExportNameAttr(S, D, AL);
break;
+ case ParsedAttr::AT_WebAssemblyExported:
+ handleWebAssemblyExportedAttr(S, D, AL);
+ break;
case ParsedAttr::AT_WebAssemblyImportModule:
handleWebAssemblyImportModuleAttr(S, D, AL);
break;
Index: clang/lib/CodeGen/TargetInfo.cpp
===================================================================
--- clang/lib/CodeGen/TargetInfo.cpp
+++ clang/lib/CodeGen/TargetInfo.cpp
@@ -777,24 +777,25 @@
CodeGen::CodeGenModule &CGM) const override {
TargetCodeGenInfo::setTargetAttributes(D, GV, CGM);
if (const auto *FD = dyn_cast_or_null<FunctionDecl>(D)) {
+ llvm::Function *Fn = cast<llvm::Function>(GV);
if (const auto *Attr = FD->getAttr<WebAssemblyImportModuleAttr>()) {
- llvm::Function *Fn = cast<llvm::Function>(GV);
llvm::AttrBuilder B;
B.addAttribute("wasm-import-module", Attr->getImportModule());
Fn->addAttributes(llvm::AttributeList::FunctionIndex, B);
}
if (const auto *Attr = FD->getAttr<WebAssemblyImportNameAttr>()) {
- llvm::Function *Fn = cast<llvm::Function>(GV);
llvm::AttrBuilder B;
B.addAttribute("wasm-import-name", Attr->getImportName());
Fn->addAttributes(llvm::AttributeList::FunctionIndex, B);
}
if (const auto *Attr = FD->getAttr<WebAssemblyExportNameAttr>()) {
- llvm::Function *Fn = cast<llvm::Function>(GV);
llvm::AttrBuilder B;
B.addAttribute("wasm-export-name", Attr->getExportName());
Fn->addAttributes(llvm::AttributeList::FunctionIndex, B);
}
+ if (const auto *Attr = FD->getAttr<WebAssemblyExportedAttr>()) {
+ Fn->addFnAttr("wasm-exported");
+ }
}
if (auto *FD = dyn_cast_or_null<FunctionDecl>(D)) {
Index: clang/include/clang/Basic/AttrDocs.td
===================================================================
--- clang/include/clang/Basic/AttrDocs.td
+++ clang/include/clang/Basic/AttrDocs.td
@@ -4165,6 +4165,16 @@
}];
}
+def WebAssemblyExportedDocs : Documentation {
+ let Category = DocCatFunction;
+ let Content = [{
+Clang supports the ``__attribute__((exported))``
+attribute for the WebAssembly target. This attribute may be attached to a
+function declaration, where it causes the be exported from the linked
+WebAssembly module.
+ }];
+}
+
def WebAssemblyImportModuleDocs : Documentation {
let Category = DocCatFunction;
let Content = [{
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -1646,6 +1646,13 @@
let Subjects = SubjectList<[Function], ErrorDiag>;
}
+def WebAssemblyExported : InheritableAttr,
+ TargetSpecificAttr<TargetWebAssembly> {
+ let Spellings = [Clang<"exported">];
+ let Documentation = [WebAssemblyExportedDocs];
+ let Subjects = SubjectList<[Function], ErrorDiag>;
+}
+
def WebAssemblyImportModule : InheritableAttr,
TargetSpecificAttr<TargetWebAssembly> {
let Spellings = [Clang<"import_module">];
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