[WebAssembly] Add multivalue and tail-call target features

[tlively]

Summary

These features will both be implemented soon, so I thought I would
save time by adding the boilerplate for both of them at the same time.

[sbc100]

Does it make sense to support the flags before we support the feature?

Otherwise lgtm.

[aheejin]

How about using multi_value/multi-value/MultiValue/MULTI-VALUE (depending on positions)? The repo name is also multi-value. https://github.com/WebAssembly/multi-value
Otherwise LGTM.

[aheejin]

In D62047#1505838, @sbc100 wrote:

Does it make sense to support the flags before we support the feature?

Otherwise lgtm.

I think this is OK; flags anyway should be added before actual feature implementation starts in order to add tests.

[tlively]

In D62047#1505878, @aheejin wrote:

How about using multi_value/multi-value/MultiValue/MULTI-VALUE (depending on positions)? The repo name is also multi-value. https://github.com/WebAssembly/multi-value
Otherwise LGTM.

From https://english.stackexchange.com/questions/118021/existence-of-multi-in-us-english:

the prefix multi is valid in American English, and usually used unhyphenated

[aheejin]

I see. LGTM either way 😂

cfe/trunk/include/clang/Driver/Options.td

 def mexception_handing : Flag<["-"], "mexception-handling">, Group<m_wasm_Features_Group>;
 def mno_exception_handing : Flag<["-"], "mno-exception-handling">, Group<m_wasm_Features_Group>;
 def matomics : Flag<["-"], "matomics">, Group<m_wasm_Features_Group>;
 def mno_atomics : Flag<["-"], "mno-atomics">, Group<m_wasm_Features_Group>;
 def mbulk_memory : Flag<["-"], "mbulk-memory">, Group<m_wasm_Features_Group>;
 def mno_bulk_memory : Flag<["-"], "mno-bulk-memory">, Group<m_wasm_Features_Group>;
 def mmutable_globals : Flag<["-"], "mmutable-globals">, Group<m_wasm_Features_Group>;
 def mno_mutable_globals : Flag<["-"], "mno-mutable-globals">, Group<m_wasm_Features_Group>;
+def mmultivalue : Flag<["-"], "mmultivalue">, Group<m_wasm_Features_Group>;
+def mno_multivalue : Flag<["-"], "mno-multivalue">, Group<m_wasm_Features_Group>;
+def mtail_call : Flag<["-"], "mtail-call">, Group<m_wasm_Features_Group>;
+def mno_tail_call : Flag<["-"], "mno-tail-call">, Group<m_wasm_Features_Group>;
 
 def mamdgpu_debugger_abi : Joined<["-"], "mamdgpu-debugger-abi=">,
   Flags<[HelpHidden]>,
   Group<m_Group>,
   HelpText<"Generate additional code for specified <version> of debugger ABI (AMDGPU only)">,
   MetaVarName<"<version>">;
 
 def mcode_object_v3 : Flag<["-"], "mcode-object-v3">, Group<m_amdgpu_Features_Group>,

cfe/trunk/lib/Basic/Targets/WebAssembly.h

class LLVM_LIBRARY_VISIBILITY WebAssemblyTargetInfo : public TargetInfo {
   } SIMDLevel = NoSIMD;
 
   bool HasNontrappingFPToInt = false;
   bool HasSignExt = false;
   bool HasExceptionHandling = false;
   bool HasBulkMemory = false;
   bool HasAtomics = false;
   bool HasMutableGlobals = false;
+  bool HasMultivalue = false;
+  bool HasTailCall = false;
 
 public:
   explicit WebAssemblyTargetInfo(const llvm::Triple &T, const TargetOptions &)
       : TargetInfo(T) {
     NoAsmVariants = true;
     SuitableAlign = 128;
     LargeArrayMinWidth = 128;
     LargeArrayAlign = 128;

cfe/trunk/lib/Basic/Targets/WebAssembly.cpp

return llvm::StringSwitch<bool>(Feature)
       .Case("simd128", SIMDLevel >= SIMD128)
       .Case("unimplemented-simd128", SIMDLevel >= UnimplementedSIMD128)
       .Case("nontrapping-fptoint", HasNontrappingFPToInt)
       .Case("sign-ext", HasSignExt)
       .Case("exception-handling", HasExceptionHandling)
       .Case("bulk-memory", HasBulkMemory)
       .Case("atomics", HasAtomics)
       .Case("mutable-globals", HasMutableGlobals)
+      .Case("multivalue", HasMultivalue)
+      .Case("tail-call", HasTailCall)
       .Default(false);
 }
 
 bool WebAssemblyTargetInfo::isValidCPUName(StringRef Name) const {
   return llvm::find(ValidCPUNames, Name) != std::end(ValidCPUNames);
 }
 
 void WebAssemblyTargetInfo::fillValidCPUList(
void WebAssemblyTargetInfo::getTargetDefines(const LangOptions &Opts,
   if (HasExceptionHandling)
     Builder.defineMacro("__wasm_exception_handling__");
   if (HasBulkMemory)
     Builder.defineMacro("__wasm_bulk_memory__");
   if (HasAtomics)
     Builder.defineMacro("__wasm_atomics__");
   if (HasMutableGlobals)
     Builder.defineMacro("__wasm_mutable_globals__");
+  if (HasMultivalue)
+    Builder.defineMacro("__wasm_multivalue__");
+  if (HasTailCall)
+    Builder.defineMacro("__wasm_tail_call__");
 }
 
 void WebAssemblyTargetInfo::setSIMDLevel(llvm::StringMap<bool> &Features,
                                          SIMDEnum Level) {
   switch (Level) {
   case UnimplementedSIMD128:
     Features["unimplemented-simd128"] = true;
     LLVM_FALLTHROUGH;
bool WebAssemblyTargetInfo::initFeatureMap(
   if (HasExceptionHandling)
     Features["exception-handling"] = true;
   if (HasBulkMemory)
     Features["bulk-memory"] = true;
   if (HasAtomics)
     Features["atomics"] = true;
   if (HasMutableGlobals)
     Features["mutable-globals"] = true;
+  if (HasMultivalue)
+    Features["multivalue"] = true;
+  if (HasTailCall)
+    Features["tail-call"] = true;
 
   return TargetInfo::initFeatureMap(Features, Diags, CPU, FeaturesVec);
 }
 
 bool WebAssemblyTargetInfo::handleTargetFeatures(
     std::vector<std::string> &Features, DiagnosticsEngine &Diags) {
   for (const auto &Feature : Features) {
     if (Feature == "+simd128") {
for (const auto &Feature : Features) {
     if (Feature == "+mutable-globals") {
       HasMutableGlobals = true;
       continue;
     }
     if (Feature == "-mutable-globals") {
       HasMutableGlobals = false;
       continue;
     }
+    if (Feature == "+multivalue") {
+      HasMultivalue = true;
+      continue;
+    }
+    if (Feature == "-multivalue") {
+      HasMultivalue = false;
+      continue;
+    }
+    if (Feature == "+tail-call") {
+      HasTailCall = true;
+      continue;
+    }
+    if (Feature == "-tail-call") {
+      HasTailCall = false;
+      continue;
+    }
 
     Diags.Report(diag::err_opt_not_valid_with_opt)
         << Feature << "-target-feature";
     return false;
   }
   return true;
 }
 

cfe/trunk/test/Preprocessor/wasm-target-features.c

 // RUN:   | FileCheck %s -check-prefix=MUTABLE-GLOBALS
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -mmutable-globals \
 // RUN:   | FileCheck %s -check-prefix=MUTABLE-GLOBALS
 //
 // MUTABLE-GLOBALS:#define __wasm_mutable_globals__ 1{{$}}
 
 // RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm32-unknown-unknown -mmultivalue \
+// RUN:   | FileCheck %s -check-prefix=MULTIVALUE
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm64-unknown-unknown -mmultivalue \
+// RUN:   | FileCheck %s -check-prefix=MULTIVALUE
+//
+// MULTIVALUE:#define __wasm_multivalue__ 1{{$}}
+
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm32-unknown-unknown -mtail-call \
+// RUN:   | FileCheck %s -check-prefix=TAIL-CALL
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm64-unknown-unknown -mtail-call \
+// RUN:   | FileCheck %s -check-prefix=TAIL-CALL
+//
+// TAIL-CALL:#define __wasm_tail_call__ 1{{$}}
+
+// RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=mvp \
 // RUN:   | FileCheck %s -check-prefix=MVP
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -mcpu=mvp \
 // RUN:   | FileCheck %s -check-prefix=MVP
 //
 // MVP-NOT:#define __wasm_simd128__
 // MVP-NOT:#define __wasm_unimplemented_simd128__
 // MVP-NOT:#define __wasm_nontrapping_fptoint__
 // MVP-NOT:#define __wasm_sign_ext__
 // MVP-NOT:#define __wasm_exception_handling__
 // MVP-NOT:#define __wasm_bulk_memory__
 // MVP-NOT:#define __wasm_atomics__
 // MVP-NOT:#define __wasm_mutable_globals__
+// MVP-NOT:#define __wasm_multivalue__
+// MVP-NOT:#define __wasm_tail_call__
 
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=bleeding-edge \
 // RUN:   | FileCheck %s -check-prefix=BLEEDING-EDGE
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -mcpu=bleeding-edge \
 // RUN:   | FileCheck %s -check-prefix=BLEEDING-EDGE
 //
 // BLEEDING-EDGE-DAG:#define __wasm_nontrapping_fptoint__ 1{{$}}
 // BLEEDING-EDGE-DAG:#define __wasm_sign_ext__ 1{{$}}
 // BLEEDING-EDGE-DAG:#define __wasm_simd128__ 1{{$}}
 // BLEEDING-EDGE-DAG:#define __wasm_atomics__ 1{{$}}
 // BLEEDING-EDGE-DAG:#define __wasm_mutable_globals__ 1{{$}}
 // BLEEDING-EDGE-NOT:#define __wasm_unimplemented_simd128__ 1{{$}}
+// BLEEDING-EDGE-NOT:#define __wasm_multivalue__ 1{{$}}
+// BLEEDING-EDGE-NOT:#define __wasm_tail_call__ 1{{$}}
 
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=bleeding-edge -mno-simd128 \
 // RUN:   | FileCheck %s -check-prefix=BLEEDING-EDGE-NO-SIMD128
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -mcpu=bleeding-edge -mno-simd128 \
 // RUN:   | FileCheck %s -check-prefix=BLEEDING-EDGE-NO-SIMD128
 //
 // BLEEDING-EDGE-NO-SIMD128-NOT:#define __wasm_simd128__

llvm/trunk/lib/Target/WebAssembly/WebAssembly.td

 def FeatureUnimplementedSIMD128 :
       SubtargetFeature<"unimplemented-simd128",
                        "SIMDLevel", "UnimplementedSIMD128",
                        "Enable 128-bit SIMD not yet implemented in engines",
                        [FeatureSIMD128]>;
 
 def FeatureAtomics : SubtargetFeature<"atomics", "HasAtomics", "true",
                                       "Enable Atomics">;
+
 def FeatureNontrappingFPToInt :
       SubtargetFeature<"nontrapping-fptoint",
                        "HasNontrappingFPToInt", "true",
                        "Enable non-trapping float-to-int conversion operators">;
 
 def FeatureSignExt :
       SubtargetFeature<"sign-ext",
                        "HasSignExt", "true",
                        "Enable sign extension operators">;
 
+def FeatureTailCall :
+      SubtargetFeature<"tail-call",
+                       "HasTailCall", "true",
+                       "Enable tail call instructions">;
+
 def FeatureExceptionHandling :
       SubtargetFeature<"exception-handling", "HasExceptionHandling", "true",
                        "Enable Wasm exception handling">;
 
 def FeatureBulkMemory :
       SubtargetFeature<"bulk-memory", "HasBulkMemory", "true",
                        "Enable bulk memory operations">;
 
+def FeatureMultivalue :
+      SubtargetFeature<"multivalue",
+                       "HasMultivalue", "true",
+                       "Enable multivalue blocks, instructions, and functions">;
+
 def FeatureMutableGlobals :
       SubtargetFeature<"mutable-globals", "HasMutableGlobals", "true",
                        "Enable mutable globals">;
 
 //===----------------------------------------------------------------------===//
 // Architectures.
 //===----------------------------------------------------------------------===//
 

llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.td

 def HasUnimplementedSIMD128 :
     Predicate<"Subtarget->hasUnimplementedSIMD128()">,
     AssemblerPredicate<"FeatureUnimplementedSIMD128", "unimplemented-simd128">;
 
 def HasAtomics :
     Predicate<"Subtarget->hasAtomics()">,
     AssemblerPredicate<"FeatureAtomics", "atomics">;
 
+def HasMultivalue :
+    Predicate<"Subtarget->hasMultivalue()">,
+    AssemblerPredicate<"FeatureMultivalue", "multivalue">;
+
 def HasNontrappingFPToInt :
     Predicate<"Subtarget->hasNontrappingFPToInt()">,
     AssemblerPredicate<"FeatureNontrappingFPToInt", "nontrapping-fptoint">;
 
 def NotHasNontrappingFPToInt :
     Predicate<"!Subtarget->hasNontrappingFPToInt()">,
     AssemblerPredicate<"!FeatureNontrappingFPToInt", "nontrapping-fptoint">;
 
 def HasSignExt :
     Predicate<"Subtarget->hasSignExt()">,
     AssemblerPredicate<"FeatureSignExt", "sign-ext">;
 
-def NotHasSignExt :
-    Predicate<"!Subtarget->hasSignExt()">,
-    AssemblerPredicate<"!FeatureSignExt", "sign-ext">;
+def HasTailCall :
+    Predicate<"Subtarget->hasTailCall()">,
+    AssemblerPredicate<"FeatureTailCall", "tail-call">;
 
 def HasExceptionHandling :
     Predicate<"Subtarget->hasExceptionHandling()">,
     AssemblerPredicate<"FeatureExceptionHandling", "exception-handling">;
 
-def NotHasExceptionHandling :
-    Predicate<"!Subtarget->hasExceptionHandling()">,
-    AssemblerPredicate<"!FeatureExceptionHandling", "exception-handling">;
-
 def HasBulkMemory :
     Predicate<"Subtarget->hasBulkMemory()">,
     AssemblerPredicate<"FeatureBulkMemory", "bulk-memory">;
 
 //===----------------------------------------------------------------------===//
 // WebAssembly-specific DAG Node Types.
 //===----------------------------------------------------------------------===//
 

llvm/trunk/lib/Target/WebAssembly/WebAssemblySubtarget.h

enum SIMDEnum {
     UnimplementedSIMD128,
   } SIMDLevel = NoSIMD;
 
   bool HasAtomics = false;
   bool HasNontrappingFPToInt = false;
   bool HasSignExt = false;
   bool HasExceptionHandling = false;
   bool HasBulkMemory = false;
+  bool HasMultivalue = false;
   bool HasMutableGlobals = false;
+  bool HasTailCall = false;
 
   /// String name of used CPU.
   std::string CPUString;
 
   /// What processor and OS we're targeting.
   Triple TargetTriple;
 
   WebAssemblyFrameLowering FrameLowering;
public:
   bool hasUnimplementedSIMD128() const {
     return SIMDLevel >= UnimplementedSIMD128;
   }
   bool hasAtomics() const { return HasAtomics; }
   bool hasNontrappingFPToInt() const { return HasNontrappingFPToInt; }
   bool hasSignExt() const { return HasSignExt; }
   bool hasExceptionHandling() const { return HasExceptionHandling; }
   bool hasBulkMemory() const { return HasBulkMemory; }
+  bool hasMultivalue() const { return HasMultivalue; }
   bool hasMutableGlobals() const { return HasMutableGlobals; }
+  bool hasTailCall() const { return HasTailCall; }
 
   /// Parses features string setting specified subtarget options. Definition of
   /// function is auto generated by tblgen.
   void ParseSubtargetFeatures(StringRef CPU, StringRef FS);
 };
 
 } // end namespace llvm
 
 #endif

llvm/trunk/test/CodeGen/WebAssembly/multivalue.ll

+; RUN: llc < %s -asm-verbose=false -verify-machineinstrs -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+multivalue | FileCheck %s
+
+; Test that the multivalue attribute is accepted
+; TODO(tlively): implement multivalue
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+%pair = type { i32, i32 }
+%packed_pair = type <{ i32, i32 }>
+
+; CHECK-LABEL: sret:
+; CHECK-NEXT: sret (i32, i32, i32) -> ()
+define %pair @sret(%pair %p) {
+  ret %pair %p
+}
+
+; CHECK-LABEL: packed_sret:
+; CHECK-NEXT: packed_sret (i32, i32, i32) -> ()
+define %packed_pair @packed_sret(%packed_pair %p) {
+  ret %packed_pair %p
+}
+
+; CHECK-LABEL: .section .custom_section.target_features
+; CHECK-NEXT: .int8 1
+; CHECK-NEXT: .int8 43
+; CHECK-NEXT: .int8 10
+; CHECK-NEXT: .ascii "multivalue"

llvm/trunk/test/CodeGen/WebAssembly/tailcall.ll

+; RUN: llc < %s -asm-verbose=false -verify-machineinstrs -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+tail-call | FileCheck %s
+
+; Test that the tail-call attribute is accepted
+; TODO(tlively): implement tail call
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+; CHECK-LABEL: recursive_tail:
+; CHECK:      i32.call $push[[L0:[0-9]+]]=, recursive_tail{{$}}
+; CHECK-NEXT: return $pop[[L0]]{{$}}
+define i32 @recursive_tail() {
+  %v = tail call i32 @recursive_tail()
+  ret i32 %v
+}
+
+; CHECK-LABEL: .section .custom_section.target_features
+; CHECK-NEXT: .int8 1
+; CHECK-NEXT: .int8 43
+; CHECK-NEXT: .int8 9
+; CHECK-NEXT: .ascii "tail-call"