[WebAssembly] Remove uses of ThreadModel

[tlively]

Summary

In the clang UI, replaces -mthread-model posix with -matomics as the
source of truth on threading. In the backend, replaces
-thread-model=posix with the atomics target feature, which is now
collected on the WebAssemblyTargetMachine along with all other used
features. These collected features will also be used to emit the
target features section in the future.

The default configuration for the backend is thread-model=posix and no
atomics, which was previously an invalid configuration. This change
makes the default valid because the thread model is ignored.

A side effect of this change is that objects are never emitted with
passive segments. It will instead be up to the linker to decide
whether sections should be active or passive based on whether atomics
are used in the final link.

[sbc100]

I think I like this.

We may find a reason down the line to allow passive to be set per-segment, but now keeping it simple and lettings the linker decide makes sense.

llvm/test/CodeGen/WebAssembly/atomic-mem-consistency.ll

1

What did this start passing? Is it because llc now has the correct default and will lower atomics to non-atomics? I guess there is no longer a way to make this fail in the way that it did before.. which is good?

[sbc100]

I certainly like that llc now does the right thing by default!

[tlively]

llvm/test/CodeGen/WebAssembly/atomic-mem-consistency.ll

1

Precisely :D

[tlively]

I'll wait and see if @aheejin has any concerns before landing.

[aheejin]

This looks a nice improvement! Thank you.

clang/include/clang/Driver/ToolChain.h

456

I think now we can delete this overridden method, because the default value for this is "posix". See Dan's commit.

clang/lib/Driver/ToolChains/WebAssembly.cpp

135

This is nicer! Given that the default values for both options were false, we didn't need to care whether a user explicitly gave it or not after all.

llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp

150

Aha, this is the info.

[sunfish]

This is still a little confusing to me. -matomic is supposed to be a subtarget flag, stating that the wasm implementation we will run on supports atomic instructions. -mthread-model posix is about the C++ interpretation -- what style implementation of memory model do we want? In the future, -matomic may become enabled by default, when enough wasm engines generally support it. However, -mthread-model single/posix may still be useful to control independently, because even with wasm engines supporting atomic, there are reasons users might still want to compile their apps single-threaded: access to linear memory with no declared max, lower overall code size, or other things.

[tlively]

In D58742#1413077, @sunfish wrote:

This is still a little confusing to me. -matomic is supposed to be a subtarget flag, stating that the wasm implementation we will run on supports atomic instructions. -mthread-model posix is about the C++ interpretation -- what style implementation of memory model do we want? In the future, -matomic may become enabled by default, when enough wasm engines generally support it. However, -mthread-model single/posix may still be useful to control independently, because even with wasm engines supporting atomic, there are reasons users might still want to compile their apps single-threaded: access to linear memory with no declared max, lower overall code size, or other things.

The only backend besides us that uses the ThreadModel at all is ARM, so we were questioning its generality. I originally shared your opinion that the available target features should be controlled separately from whether or not the user wants threads, but in reality we get to use the atomics feature if and only if the user opts in to threads. Because of this, ignoring the thread model entirely like most other backends lets us have a much simpler user interface that is not invalid by default.

I expect with this model we would never turn on atomics by default (since we don't want multithreaded by default), and most users would get them by using -pthread. This is very close in UI to native targets. The -matomics option is only there for users who are doing weird threaded things but don't want libpthread for some reason.

clang/include/clang/Driver/ToolChain.h

456

I did delete the overridden method below in clang/lib/Driver/ToolChains/WebAssembly.cpp. This is restoring the base class implementation to the way it was before your CL added the ArgList argument, since we no longer need it.

[aheejin]

clang/include/clang/Driver/ToolChain.h

456

Oh sorry, I thought this file was WebAssembly.cpp...

[sbc100]

In D58742#1413077, @sunfish wrote:

This is still a little confusing to me. -matomic is supposed to be a subtarget flag, stating that the wasm implementation we will run on supports atomic instructions. -mthread-model posix is about the C++ interpretation -- what style implementation of memory model do we want? In the future, -matomic may become enabled by default, when enough wasm engines generally support it. However, -mthread-model single/posix may still be useful to control independently, because even with wasm engines supporting atomic, there are reasons users might still want to compile their apps single-threaded: access to linear memory with no declared max, lower overall code size, or other things.

" -mthread-model posix is about the C++ interpretation" .. are you sure about that? git grep getThreadModel shows basically no use of this.

Digging a little deeper.. The thread-model thing was introduced here: https://reviews.llvm.org/D4984 and was clearly related to the underlying architecture. Apart from wasm nobody else has ever starting using this is given it any other meaning as far as I can tell. Maybe I'm missing something?

[sunfish]

Wasm gives users reasons to want -mthread-model single that other architectures don't, even when -matomics is enabled by default.

When shared memory is used, wasm requires modules to declare a max memory size, which is a burden on applications that want to use dynamic amounts of memory. Wasm is more sensitive to code size than most other architectures. And, interoperating with single-threaded JS is easier from single-threaded wasm (JS has access to SharedArrayBuffer and atomics, but not all JS wants to use that).

[sbc100]

In D58742#1413979, @sunfish wrote:

Wasm gives users reasons to want -mthread-model single that other architectures don't, even when -matomics is enabled by default.

When shared memory is used, wasm requires modules to declare a max memory size, which is a burden on applications that want to use dynamic amounts of memory. Wasm is more sensitive to code size than most other architectures. And, interoperating with single-threaded JS is easier from single-threaded wasm (JS has access to SharedArrayBuffer and atomics, but not all JS wants to use that).

Yes, but I don't see how that is related to this change. I don't think there is a plan to make -matomics the default, and even if we did users would be free to disable it.

My understanding is that the default for clang and llvm and lld for the foreseeable will be to target single threaded mode, with non-shared-memory. This CL doesn't change that.

clang/include/clang/Driver/Options.td

 def mno_unimplemented_simd128 : Flag<["-"], "mno-unimplemented-simd128">, Group<m_wasm_Features_Group>;
 def mno_simd128 : Flag<["-"], "mno-simd128">, Group<m_wasm_Features_Group>;
 def mnontrapping_fptoint : Flag<["-"], "mnontrapping-fptoint">, Group<m_wasm_Features_Group>;
 def mno_nontrapping_fptoint : Flag<["-"], "mno-nontrapping-fptoint">, Group<m_wasm_Features_Group>;
 def msign_ext : Flag<["-"], "msign-ext">, Group<m_wasm_Features_Group>;
 def mno_sign_ext : Flag<["-"], "mno-sign-ext">, Group<m_wasm_Features_Group>;
 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 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>">;

clang/include/clang/Driver/ToolChain.h

public:
   /// GetExceptionModel - Return the tool chain exception model.
   virtual llvm::ExceptionHandling
   GetExceptionModel(const llvm::opt::ArgList &Args) const;
 
   /// SupportsEmbeddedBitcode - Does this tool chain support embedded bitcode.
   virtual bool SupportsEmbeddedBitcode() const { return false; }
 
   /// getThreadModel() - Which thread model does this target use?
-  virtual std::string getThreadModel(const llvm::opt::ArgList &) const {
-    return "posix";
-  }
+  virtual std::string getThreadModel() const { return "posix"; }
 
   /// isThreadModelSupported() - Does this target support a thread model?
   virtual bool isThreadModelSupported(const StringRef Model) const;
 
   /// ComputeLLVMTriple - Return the LLVM target triple to use, after taking
   /// command line arguments into account.
   virtual std::string
   ComputeLLVMTriple(const llvm::opt::ArgList &Args,

clang/lib/Driver/Driver.cpp

void Driver::PrintVersion(const Compilation &C, raw_ostream &OS) const {
   OS << "Target: " << TC.getTripleString() << '\n';
 
   // Print the threading model.
   if (Arg *A = C.getArgs().getLastArg(options::OPT_mthread_model)) {
     // Don't print if the ToolChain would have barfed on it already
     if (TC.isThreadModelSupported(A->getValue()))
       OS << "Thread model: " << A->getValue();
   } else
-    OS << "Thread model: " << TC.getThreadModel(C.getArgs());
+    OS << "Thread model: " << TC.getThreadModel();
   OS << '\n';
 
   // Print out the install directory.
   OS << "InstalledDir: " << InstalledDir << '\n';
 
   // If configuration file was used, print its path.
   if (!ConfigFile.empty())
     OS << "Configuration file: " << ConfigFile << '\n';

clang/lib/Driver/ToolChains/Clang.cpp

#endif
   CmdArgs.push_back("-mthread-model");
   if (Arg *A = Args.getLastArg(options::OPT_mthread_model)) {
     if (!TC.isThreadModelSupported(A->getValue()))
       D.Diag(diag::err_drv_invalid_thread_model_for_target)
           << A->getValue() << A->getAsString(Args);
     CmdArgs.push_back(A->getValue());
   }
   else
-    CmdArgs.push_back(Args.MakeArgString(TC.getThreadModel(Args)));
+    CmdArgs.push_back(Args.MakeArgString(TC.getThreadModel()));
 
   Args.AddLastArg(CmdArgs, options::OPT_fveclib);
 
   if (Args.hasFlag(options::OPT_fmerge_all_constants,
                    options::OPT_fno_merge_all_constants, false))
     CmdArgs.push_back("-fmerge-all-constants");
 
   if (Args.hasFlag(options::OPT_fno_delete_null_pointer_checks,

clang/lib/Driver/ToolChains/WebAssembly.h

private:
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;
   void AddClangCXXStdlibIncludeArgs(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
-  std::string getThreadModel(const llvm::opt::ArgList &) const override;
 
   const char *getDefaultLinker() const override { return "wasm-ld"; }
 
   Tool *buildLinker() const override;
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_WEBASSEMBLY_H

clang/lib/Driver/ToolChains/WebAssembly.cpp

 #include "llvm/Option/ArgList.h"
 
 using namespace clang::driver;
 using namespace clang::driver::tools;
 using namespace clang::driver::toolchains;
 using namespace clang;
 using namespace llvm::opt;
 
-void parseThreadArgs(const Driver &Driver, const ArgList &DriverArgs,
-                     bool &Pthread, StringRef &ThreadModel,
-                     bool CheckForErrors = true) {
-  // Default value for -pthread / -mthread-model options, each being false /
-  // "single".
-  Pthread =
-      DriverArgs.hasFlag(options::OPT_pthread, options::OPT_no_pthread, false);
-  ThreadModel =
-      DriverArgs.getLastArgValue(options::OPT_mthread_model, "single");
-  if (!CheckForErrors)
-    return;
-
-  // Did user explicitly specify -mthread-model / -pthread?
-  bool HasThreadModel = DriverArgs.hasArg(options::OPT_mthread_model);
-  bool HasPthread = Pthread && DriverArgs.hasArg(options::OPT_pthread);
-  // '-pthread' cannot be used with '-mthread-model single'
-  if (HasPthread && HasThreadModel && ThreadModel == "single")
-    Driver.Diag(diag::err_drv_argument_not_allowed_with)
-        << "-pthread" << "-mthread-model single";
-}
-
 wasm::Linker::Linker(const ToolChain &TC)
     : GnuTool("wasm::Linker", "lld", TC) {}
 
 /// Following the conventions in https://wiki.debian.org/Multiarch/Tuples,
 /// we remove the vendor field to form the multiarch triple.
 static std::string getMultiarchTriple(const Driver &D,
                                       const llvm::Triple &TargetTriple,
                                       StringRef SysRoot) {

 
 void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
                                         ArgStringList &CC1Args,
                                         Action::OffloadKind) const {
   if (DriverArgs.hasFlag(clang::driver::options::OPT_fuse_init_array,
                          options::OPT_fno_use_init_array, true))
     CC1Args.push_back("-fuse-init-array");
 
-  // Either '-mthread-model posix' or '-pthread' sets '-target-feature
-  // +atomics'. We intentionally didn't create '-matomics' and set the atomics
-  // target feature here depending on the other two options.
-  bool Pthread = false;
-  StringRef ThreadModel = "";
-  parseThreadArgs(getDriver(), DriverArgs, Pthread, ThreadModel);
-  if (Pthread || ThreadModel != "single") {
+  // '-pthread' implies '-target-feature +atomics' and
+  // '-target-feature +bulk-memory'
+  if (DriverArgs.hasFlag(options::OPT_pthread, options::OPT_no_pthread,
+                         false)) {
+    if (DriverArgs.hasFlag(options::OPT_mno_atomics, options::OPT_matomics,
+                           false))
+      getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+          << "-pthread"
+          << "-mno-atomics";
+    if (DriverArgs.hasFlag(options::OPT_mno_bulk_memory,
+                           options::OPT_mbulk_memory, false))
+      getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+          << "-pthread"
+          << "-mno-bulk-memory";
     CC1Args.push_back("-target-feature");
     CC1Args.push_back("+atomics");
+    CC1Args.push_back("-target-feature");
+    CC1Args.push_back("+bulk-memory");
+  }
+
+  // '-matomics' implies '-mbulk-memory'
+  if (DriverArgs.hasFlag(options::OPT_matomics, options::OPT_mno_atomics,
+                         false)) {
+    if (DriverArgs.hasFlag(options::OPT_mno_bulk_memory,
+                           options::OPT_mbulk_memory, false))
+      getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+          << "-matomics"
+          << "-mno-bulk-memory";
+    CC1Args.push_back("-target-feature");
+    CC1Args.push_back("+bulk-memory");
   }
 }
 
 ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {
   return ToolChain::RLT_CompilerRT;
 }
 
 ToolChain::CXXStdlibType
case ToolChain::CST_Libcxx:
     CmdArgs.push_back("-lc++");
     CmdArgs.push_back("-lc++abi");
     break;
   case ToolChain::CST_Libstdcxx:
     llvm_unreachable("invalid stdlib name");
   }
 }
 
-std::string WebAssembly::getThreadModel(const ArgList &DriverArgs) const {
-  // The WebAssembly MVP does not yet support threads. We set this to "posix"
-  // when '-pthread' is set.
-  bool Pthread = false;
-  StringRef ThreadModel = "";
-  parseThreadArgs(getDriver(), DriverArgs, Pthread, ThreadModel, false);
-  if (Pthread)
-    return "posix";
-  return ThreadModel;
-}
-
 Tool *WebAssembly::buildLinker() const {
   return new tools::wasm::Linker(*this);
 }

clang/test/Driver/wasm-toolchain.c

 // LINK_OPT_KNOWN: wasm-ld{{.*}}" "-L/foo/lib/wasm32-wasi-musl" "crt1.o" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"
 
 // A basic C compile command-line with known OS.
 
 // RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-wasi-musl --sysroot=/foo %s 2>&1 | FileCheck -check-prefix=COMPILE %s
 // COMPILE: clang{{.*}}" "-cc1" {{.*}} "-internal-isystem" "/foo/include/wasm32-wasi-musl" "-internal-isystem" "/foo/include"
 
 // Thread-related command line tests.
-// - '-mthread-model' sets '-target-feature +matomics'
-// - '-phread' sets both '-target-featuer +atomics' and '-mthread-model posix'
-
-// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s -mthread-model posix 2>&1 | FileCheck -check-prefix=POSIX %s
-// POSIX: clang{{.*}}" "-cc1" {{.*}} "-target-feature" "+atomics"
 
+// '-pthread' sets '-target-feature +atomics' and '-target-feature +bulk-memory'
 // RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s -pthread 2>&1 | FileCheck -check-prefix=PTHREAD %s
-// PTHREAD: clang{{.*}}" "-cc1" {{.*}} "-mthread-model" "posix" {{.*}} "-target-feature" "+atomics"
+// PTHREAD: clang{{.*}}" "-cc1" {{.*}} "-target-feature" "+atomics" "-target-feature" "+bulk-memory"
 
-// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s -pthread -mthread-model single 2>&1 | FileCheck -check-prefix=THREAD_OPT_ERROR %s
-// THREAD_OPT_ERROR: invalid argument '-pthread' not allowed with '-mthread-model single'
+// '-pthread' not allowed with '-mno-atomics'
+// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s -pthread -mno-atomics 2>&1 | FileCheck -check-prefix=PTHREAD_NO_ATOMICS %s
+// PTHREAD_NO_ATOMICS: invalid argument '-pthread' not allowed with '-mno-atomics'
+
+// '-pthread' not allowed with '-mno-bulk-memory'
+// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s -pthread -mno-bulk-memory 2>&1 | FileCheck -check-prefix=PTHREAD_NO_BULKMEM %s
+// PTHREAD_NO_BULKMEM: invalid argument '-pthread' not allowed with '-mno-bulk-memory'
+
+// '-matomics' not allowed with '-mno-bulk-memory'
+// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s -matomics -mno-bulk-memory 2>&1 | FileCheck -check-prefix=ATOMICS_NO_BULKMEM %s
+// ATOMICS_NO_BULKMEM: invalid argument '-matomics' not allowed with '-mno-bulk-memory'

clang/test/Preprocessor/wasm-target-features.c

 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -msimd128 \
 // RUN:   | FileCheck %s -check-prefix=SIMD128
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -msimd128 \
 // RUN:   | FileCheck %s -check-prefix=SIMD128
 //
 // SIMD128:#define __wasm_simd128__ 1{{$}}
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -munimplemented-simd128 \
 // RUN:   | FileCheck %s -check-prefix=SIMD128-UNIMPLEMENTED
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -munimplemented-simd128 \
 // RUN:   | FileCheck %s -check-prefix=SIMD128-UNIMPLEMENTED
 //
 // SIMD128-UNIMPLEMENTED:#define __wasm_unimplemented_simd128__ 1{{$}}
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mnontrapping-fptoint \
 // RUN:   | FileCheck %s -check-prefix=NONTRAPPING-FPTOINT
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -mnontrapping-fptoint \
 // RUN:   | FileCheck %s -check-prefix=NONTRAPPING-FPTOINT
 //
 // NONTRAPPING-FPTOINT:#define __wasm_nontrapping_fptoint__ 1{{$}}
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -msign-ext \
 // RUN:   | FileCheck %s -check-prefix=SIGN-EXT
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -msign-ext \
 // RUN:   | FileCheck %s -check-prefix=SIGN-EXT
 //
 // SIGN-EXT:#define __wasm_sign_ext__ 1{{$}}
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mexception-handling \
 // RUN:   | FileCheck %s -check-prefix=EXCEPTION-HANDLING
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -mexception-handling \
 // RUN:   | FileCheck %s -check-prefix=EXCEPTION-HANDLING
 //
 // EXCEPTION-HANDLING:#define __wasm_exception_handling__ 1{{$}}
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mbulk-memory \
 // RUN:   | FileCheck %s -check-prefix=BULK-MEMORY
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -mbulk-memory \
 // RUN:   | FileCheck %s -check-prefix=BULK-MEMORY
 //
 // BULK-MEMORY:#define __wasm_bulk_memory__ 1{{$}}
-//
-// We don't use -matomics directly and '-mthread-model posix' sets the atomics
-// target feature.
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
-// RUN:     -target wasm32-unknown-unknown -mthread-model posix \
+// RUN:     -target wasm32-unknown-unknown -matomics \
 // RUN:   | FileCheck %s -check-prefix=ATOMICS
 // RUN: %clang -E -dM %s -o - 2>&1 \
-// RUN:     -target wasm64-unknown-unknown -mthread-model posix \
+// RUN:     -target wasm64-unknown-unknown -matomics \
 // RUN:   | FileCheck %s -check-prefix=ATOMICS
 //
-// ATOMICS:#define __wasm_atomics__ 1{{$}}
-//
+// ATOMICS-DAG:#define __wasm_atomics__ 1{{$}}
+// ATOMICS-DAG:#define __wasm_bulk_memory__ 1{{$}}
+
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm32-unknown-unknown -pthread \
+// RUN:   | FileCheck %s -check-prefix=PTHREAD
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm64-unknown-unknown -pthread \
+// RUN:   | FileCheck %s -check-prefix=PTHREAD
+//
+// PTHREAD-DAG:#define __wasm_atomics__ 1{{$}}
+// PTHREAD-DAG:#define __wasm_bulk_memory__ 1{{$}}
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=mvp \
 // RUN:   | FileCheck %s -check-prefix=MVP
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -mcpu=mvp \
 // RUN:   | FileCheck %s -check-prefix=MVP
 //
 // MVP-NOT:#define __wasm_simd128__
 // MVP-NOT:#define __wasm_unimplemented_simd128__
 // MVP-NOT:#define __wasm_nontrapping_fptoint__
 // MVP-NOT:#define __wasm_sign_ext__
 // MVP-NOT:#define __wasm_exception_handling__
 // MVP-NOT:#define __wasm_bulk_memory__
 // MVP-NOT:#define __wasm_atomics__
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=bleeding-edge \
 // RUN:   | FileCheck %s -check-prefix=BLEEDING-EDGE
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm64-unknown-unknown -mcpu=bleeding-edge \
 // RUN:   | FileCheck %s -check-prefix=BLEEDING-EDGE
 //
 // BLEEDING-EDGE-DAG:#define __wasm_nontrapping_fptoint__ 1{{$}}
 // BLEEDING-EDGE-DAG:#define __wasm_sign_ext__ 1{{$}}
 // BLEEDING-EDGE-DAG:#define __wasm_simd128__ 1{{$}}
 // BLEEDING-EDGE-DAG:#define __wasm_atomics__ 1{{$}}
 // BLEEDING-EDGE-NOT:#define __wasm_unimplemented_simd128__ 1{{$}}
-//
+
 // 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__

lld/test/wasm/init-fini.ll

-; RUN: llc -filetype=obj -thread-model=single -o %t.o %s
-; RUN: llc -filetype=obj -thread-model=single %S/Inputs/global-ctor-dtor.ll -o %t.global-ctor-dtor.o
+; RUN: llc -filetype=obj -o %t.o %s
+; RUN: llc -filetype=obj %S/Inputs/global-ctor-dtor.ll -o %t.global-ctor-dtor.o
 
 target triple = "wasm32-unknown-unknown"
 
 define hidden void @func1() {
 entry:
   ret void
 }
 

lld/test/wasm/lto/atomics.ll

 ; RUN: llvm-as %s -o %t.o
 ; RUN: wasm-ld %t.o -o %t.wasm -lto-O0
-; Atomic operations with fail to compile if the ThreadModel is not
-; correctly set to Single (i.e. if atomics are not lowered to regular ops).
+
+; Atomic operations will not fail to compile if atomics are not
+; enabled because LLVM atomics will be lowered to regular ops.
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown-wasm"
 
 @foo = hidden global i32 1
 
 define void @_start() {
   %1 = load atomic i32, i32* @foo unordered, align 4
   ret void
 }

lld/wasm/LTO.cpp

 static std::unique_ptr<lto::LTO> createLTO() {
   lto::Config C;
   C.Options = initTargetOptionsFromCodeGenFlags();
 
   // Always emit a section per function/data with LTO.
   C.Options.FunctionSections = true;
   C.Options.DataSections = true;
 
-  // Wasm currently only supports ThreadModel::Single
-  C.Options.ThreadModel = ThreadModel::Single;
-
   C.DisableVerify = Config->DisableVerify;
   C.DiagHandler = diagnosticHandler;
   C.OptLevel = Config->LTOO;
   C.MAttrs = getMAttrs();
   C.CGOptLevel = args::getCGOptLevel(Config->LTOO);
 
   if (Config->Relocatable)
     C.RelocModel = None;

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

MCSection *TargetLoweringObjectFileWasm::getExplicitSectionGlobal(
   if (const Comdat *C = getWasmComdat(GO)) {
     Group = C->getName();
   }
 
   MCSectionWasm* Section =
       getContext().getWasmSection(Name, Kind, Group,
                                   MCContext::GenericSectionID);
 
-  if (TM.Options.ThreadModel != ThreadModel::Single)
-    Section->setPassive();
-
   return Section;
 }
 
 static MCSectionWasm *selectWasmSectionForGlobal(
     MCContext &Ctx, const GlobalObject *GO, SectionKind Kind, Mangler &Mang,
     const TargetMachine &TM, bool EmitUniqueSection, unsigned *NextUniqueID) {
   StringRef Group = "";
   if (const Comdat *C = getWasmComdat(GO)) {
if (EmitUniqueSection && UniqueSectionNames) {
     TM.getNameWithPrefix(Name, GO, Mang, true);
   }
   unsigned UniqueID = MCContext::GenericSectionID;
   if (EmitUniqueSection && !UniqueSectionNames) {
     UniqueID = *NextUniqueID;
     (*NextUniqueID)++;
   }
 
-  MCSectionWasm* Section = Ctx.getWasmSection(Name, Kind, Group, UniqueID);
-  if (Section->isWasmData() && TM.Options.ThreadModel != ThreadModel::Single)
-    Section->setPassive();
-
-  return Section;
+  return Ctx.getWasmSection(Name, Kind, Group, UniqueID);
 }
 
 MCSection *TargetLoweringObjectFileWasm::SelectSectionForGlobal(
     const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
 
   if (Kind.isCommon())
     report_fatal_error("mergable sections not supported yet on wasm");
 

llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.h

 #include "WebAssemblySubtarget.h"
 #include "llvm/Target/TargetMachine.h"
 
 namespace llvm {
 
 class WebAssemblyTargetMachine final : public LLVMTargetMachine {
   std::unique_ptr<TargetLoweringObjectFile> TLOF;
   mutable StringMap<std::unique_ptr<WebAssemblySubtarget>> SubtargetMap;
+  mutable FeatureBitset UsedFeatures;
 
 public:
   WebAssemblyTargetMachine(const Target &T, const Triple &TT, StringRef CPU,
                            StringRef FS, const TargetOptions &Options,
                            Optional<Reloc::Model> RM,
                            Optional<CodeModel::Model> CM, CodeGenOpt::Level OL,
                            bool JIT);
 
   ~WebAssemblyTargetMachine() override;
+
+  const WebAssemblySubtarget *getSubtargetImpl(std::string CPU,
+                                               std::string FS) const;
   const WebAssemblySubtarget *
   getSubtargetImpl(const Function &F) const override;
 
   // Pass Pipeline Configuration
   TargetPassConfig *createPassConfig(PassManagerBase &PM) override;
 
   TargetLoweringObjectFile *getObjFileLowering() const override {
     return TLOF.get();
   }
 
+  FeatureBitset getUsedFeatures() const { return UsedFeatures; }
+
   TargetTransformInfo getTargetTransformInfo(const Function &F) override;
 
   bool usesPhysRegsForPEI() const override { return false; }
 };
 
 } // end namespace llvm
 
 #endif

llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp

WebAssemblyTargetMachine::WebAssemblyTargetMachine(
   // WebAssembly treats each function as an independent unit. Force
   // -ffunction-sections, effectively, so that we can emit them independently.
   this->Options.FunctionSections = true;
   this->Options.DataSections = true;
   this->Options.UniqueSectionNames = true;
 
   initAsmInfo();
 
+  // Create a subtarget using the unmodified target machine features to
+  // initialize the used feature set with explicitly enabled features.
+  getSubtargetImpl(getTargetCPU(), getTargetFeatureString());
+
   // Note that we don't use setRequiresStructuredCFG(true). It disables
   // optimizations than we're ok with, and want, such as critical edge
   // splitting and tail merging.
 }
 
 WebAssemblyTargetMachine::~WebAssemblyTargetMachine() = default; // anchor.
 
 const WebAssemblySubtarget *
+WebAssemblyTargetMachine::getSubtargetImpl(std::string CPU,
+                                           std::string FS) const {
+  auto &I = SubtargetMap[CPU + FS];
+  if (!I) {
+    I = llvm::make_unique<WebAssemblySubtarget>(TargetTriple, CPU, FS, *this);
+    UsedFeatures |= I->getFeatureBits();
+  }
+  return I.get();
+}
+
+const WebAssemblySubtarget *
 WebAssemblyTargetMachine::getSubtargetImpl(const Function &F) const {
   Attribute CPUAttr = F.getFnAttribute("target-cpu");
   Attribute FSAttr = F.getFnAttribute("target-features");
 
   std::string CPU = !CPUAttr.hasAttribute(Attribute::None)
                         ? CPUAttr.getValueAsString().str()
                         : TargetCPU;
   std::string FS = !FSAttr.hasAttribute(Attribute::None)
                        ? FSAttr.getValueAsString().str()
                        : TargetFS;
 
-  auto &I = SubtargetMap[CPU + FS];
-  if (!I) {
-    // This needs to be done before we create a new subtarget since any
-    // creation will depend on the TM and the code generation flags on the
-    // function that reside in TargetOptions.
-    resetTargetOptions(F);
-    I = llvm::make_unique<WebAssemblySubtarget>(TargetTriple, CPU, FS, *this);
-  }
-  return I.get();
+
+  return getSubtargetImpl(CPU, FS);
 }
 
 namespace {
 class StripThreadLocal final : public ModulePass {
   // The default thread model for wasm is single, where thread-local variables
   // are identical to regular globals and should be treated the same. So this
   // pass just converts all GlobalVariables to NotThreadLocal
   static char ID;

 }
 
 //===----------------------------------------------------------------------===//
 // The following functions are called from lib/CodeGen/Passes.cpp to modify
 // the CodeGen pass sequence.
 //===----------------------------------------------------------------------===//
 
 void WebAssemblyPassConfig::addIRPasses() {
-  if (TM->Options.ThreadModel == ThreadModel::Single) {
-    // In "single" mode, atomics get lowered to non-atomics.
-    addPass(createLowerAtomicPass());
-    addPass(new StripThreadLocal());
-  } else {
+  if (static_cast<WebAssemblyTargetMachine *>(TM)
+          ->getUsedFeatures()[WebAssembly::FeatureAtomics]) {
     // Expand some atomic operations. WebAssemblyTargetLowering has hooks which
     // control specifically what gets lowered.
     addPass(createAtomicExpandPass());
+  } else {
+    // If atomics are not enabled, they get lowered to non-atomics.
+    addPass(createLowerAtomicPass());
+    addPass(new StripThreadLocal());
   }
 
   // Add signatures to prototype-less function declarations
   addPass(createWebAssemblyAddMissingPrototypes());
 
   // Lower .llvm.global_dtors into .llvm_global_ctors with __cxa_atexit calls.
   addPass(createWebAssemblyLowerGlobalDtors());
 

llvm/test/CodeGen/WebAssembly/atomic-mem-consistency.ll

-; RUN: not llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt
 ; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+atomics,+sign-ext | FileCheck %s
 
 ; Currently all wasm atomic memory access instructions are sequentially
 ; consistent, so even if LLVM IR specifies weaker orderings than that, we
 ; should upgrade them to sequential ordering and treat them in the same way.
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"

llvm/test/CodeGen/WebAssembly/atomic-rmw.ll

-; RUN: not llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-keep-registers
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-keep-registers
 ; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+atomics,+sign-ext | FileCheck %s
 
 ; Test atomic RMW (read-modify-write) instructions are assembled properly.
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
 
 ;===----------------------------------------------------------------------------

llvm/test/CodeGen/WebAssembly/global.ll

-; RUN: llc < %s -thread-model=single -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s --check-prefixes=CHECK,SINGLE
-; RUN: llc < %s -thread-model=posix -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s --check-prefixes=CHECK,THREADS
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=-atomics | FileCheck %s
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+atomics | FileCheck %s
 
 ; Test that globals assemble as expected.
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
 
 ; CHECK-NOT: llvm.used
 ; CHECK-NOT: llvm.metadata

 ; CHECK:      ptr:
 ; CHECK-NEXT: .int32 arr+80
 ; CHECK-NEXT: .size ptr, 4
 @arr = global [128 x i32] zeroinitializer, align 16
 @ptr = global i32* getelementptr inbounds ([128 x i32], [128 x i32]* @arr, i32 0, i32 20), align 4
 
 ; Constant global.
 ; CHECK: .type    rom,@object{{$}}
-; SINGLE: .section .rodata.rom,""
-; THREADS: .section .rodata.rom,"passive"
+; CHECK: .section .rodata.rom,""
 ; CHECK: .globl   rom{{$}}
 ; CHECK: .p2align   4{{$}}
 ; CHECK: rom:
 ; CHECK: .skip    512{{$}}
 ; CHECK: .size    rom, 512{{$}}
 @rom = constant [128 x i32] zeroinitializer, align 16
 
 ; CHECK: .type       array,@object
 ; CHECK: array:
 ; CHECK-NEXT: .skip       8
 ; CHECK-NEXT: .size       array, 8
 ; CHECK: .type       pointer_to_array,@object
-; SINGLE-NEXT: .section    .rodata.pointer_to_array,""
-; THREADS-NEXT: .section    .rodata.pointer_to_array,"passive"
+; CHECK-NEXT: .section    .rodata.pointer_to_array,""
 ; CHECK-NEXT: .globl      pointer_to_array
 ; CHECK-NEXT: .p2align      2
 ; CHECK-NEXT: pointer_to_array:
 ; CHECK-NEXT: .int32      array+4
 ; CHECK-NEXT: .size       pointer_to_array, 4
 @array = internal constant [8 x i8] zeroinitializer, align 1
 @pointer_to_array = constant i8* getelementptr inbounds ([8 x i8], [8 x i8]* @array, i32 0, i32 4), align 4
 
 ; Handle external objects with opaque type.
 %struct.ASTRUCT = type opaque
 @g_struct = external global %struct.ASTRUCT, align 1
 define i32 @address_of_opaque()  {
   ret i32 ptrtoint (%struct.ASTRUCT* @g_struct to i32)
 }

llvm/test/CodeGen/WebAssembly/tls.ll

-; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -thread-model=single | FileCheck --check-prefix=SINGLE %s
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck --check-prefix=SINGLE %s
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
 
 ; SINGLE-LABEL: address_of_tls:
 define i32 @address_of_tls() {
   ; SINGLE: i32.const $push0=, tls
   ; SINGLE-NEXT: return $pop0
   ret i32 ptrtoint(i32* @tls to i32)
 }
 
 ; SINGLE: .type tls,@object
 ; SINGLE-NEXT: .section .bss.tls,"",@
 ; SINGLE-NEXT: .p2align 2
 ; SINGLE-NEXT: tls:
 ; SINGLE-NEXT: .int32 0
 @tls = internal thread_local global i32 0

llvm/test/CodeGen/WebAssembly/vtable.ll

-; RUN: llc < %s -asm-verbose=false -thread-model=single -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s --check-prefix=TYPEINFONAME
-; RUN: llc < %s -asm-verbose=false -thread-model=single -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s --check-prefix=VTABLE
-; RUN: llc < %s -asm-verbose=false -thread-model=single -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s --check-prefix=TYPEINFO
+; RUN: llc < %s -asm-verbose=false -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s --check-prefix=TYPEINFONAME
+; RUN: llc < %s -asm-verbose=false -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s --check-prefix=VTABLE
+; RUN: llc < %s -asm-verbose=false -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s --check-prefix=TYPEINFO
 
 ; Test that simple vtables assemble as expected.
 ;
 ; The class hierarchy is:
 ;   struct A;
 ;   struct B : public A;
 ;   struct C : public A;
 ;   struct D : public B;

llvm/test/MC/WebAssembly/bss.ll

-; RUN: llc -filetype=obj -thread-model=single %s -o - | obj2yaml | FileCheck %s
+; RUN: llc -filetype=obj %s -o - | obj2yaml | FileCheck %s
 
 target triple = "wasm32-unknown-unknown"
 
 @g0 = global i8* null, align 4
 @g1 = global i32 0, align 4
 
 %union.u1 = type {}
 @foo = global %union.u1 zeroinitializer, align 1

llvm/test/MC/WebAssembly/comdat.ll

-; RUN: llc -filetype=obj -thread-model=single %s -o - | obj2yaml | FileCheck %s
+; RUN: llc -filetype=obj %s -o - | obj2yaml | FileCheck %s
 
 target triple = "wasm32-unknown-unknown"
 
 ; Import a function just so we can check the index arithmetic for
 ; WASM_COMDAT_FUNCTION entries is performed correctly
 declare i32 @funcImport()
 define i32 @callImport() {
 entry:

llvm/test/MC/WebAssembly/debug-info.ll

-; RUN: llc -filetype=obj -thread-model=single %s -o - | llvm-readobj -r -s -symbols | FileCheck %s
+; RUN: llc -filetype=obj %s -o - | llvm-readobj -r -s -symbols | FileCheck %s
 
 ; CHECK: Format: WASM
 ; CHECK-NEXT:Arch: wasm32
 ; CHECK-NEXT:AddressSize: 32bit
 ; CHECK-NEXT:Sections [
 ; CHECK-NEXT:  Section {
 ; CHECK-NEXT:    Type: TYPE (0x1)
 ; CHECK-NEXT:    Size: 4

llvm/test/MC/WebAssembly/explicit-sections.ll

-; RUN: llc -filetype=obj -thread-model=single %s -o - | obj2yaml | FileCheck %s
+; RUN: llc -filetype=obj %s -o - | obj2yaml | FileCheck %s
 
 target triple = "wasm32-unknown-unknown"
 
 %struct.bd = type { i32, i8 }
 
 @global0 = global i32 8, align 8
 @global1 = global %struct.bd  { i32 1, i8 3 }, align 8, section ".sec1"
 @global2 = global i64 7, align 8, section ".sec1"

llvm/test/MC/WebAssembly/external-data.ll

-; RUN: llc -filetype=obj -thread-model=single %s -o - | obj2yaml | FileCheck %s
+; RUN: llc -filetype=obj %s -o - | obj2yaml | FileCheck %s
 
 target triple = "wasm32-unknown-unknown"
 
 ; Verify relocations are correctly generated for addresses of externals
 ; in the data section.
 
 @myimport = external global i32, align 4
 

llvm/test/MC/WebAssembly/external-func-address.ll

-; RUN: llc -filetype=obj -thread-model=single %s -o - | obj2yaml | FileCheck %s
+; RUN: llc -filetype=obj %s -o - | obj2yaml | FileCheck %s
 
 target triple = "wasm32-unknown-unknown"
 
 ; Verify that addresses of external functions generate correctly typed
 ; imports and relocations of type R_TABLE_INDEX_I32.
 
 declare void @f0(i32) #0
 @ptr_to_f0 = hidden global void (i32)* @f0, align 4

llvm/test/MC/WebAssembly/global-ctor-dtor.ll

-; RUN: llc -filetype=obj -thread-model=single %s -o - | obj2yaml | FileCheck %s
+; RUN: llc -filetype=obj %s -o - | obj2yaml | FileCheck %s
 
 target triple = "wasm32-unknown-unknown"
 
 @global1 = global i32 1025, align 8
 
 declare void @func0()
 declare void @func1()
 declare void @func2()

llvm/test/MC/WebAssembly/init-flags.ll

-; RUN: llc -filetype=obj %s -thread-model=single -o - | obj2yaml | FileCheck %s --check-prefix=SINGLE
-; RUN: llc -filetype=obj %s -thread-model=posix -o - | obj2yaml | FileCheck %s --check-prefix=THREADS
-
-; Test that setting thread-model=posix causes data segments to be
-; emitted as passive segments (i.e. have InitFlags set to 1).
-
-target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
-target triple = "wasm32-unknown-unknown"
-
-@str = private unnamed_addr constant [7 x i8] c"Hello!\00", align 1
-
-; SINGLE:       - Type:            DATA
-; SINGLE-NEXT:    Segments:
-; SINGLE-NEXT:      - SectionOffset:   6
-; SINGLE-NEXT:        InitFlags:       0
-; SINGLE-NEXT:        Offset:
-; SINGLE-NEXT:          Opcode:          I32_CONST
-; SINGLE-NEXT:          Value:           0
-; SINGLE-NEXT:        Content:         48656C6C6F2100
-
-; THREADS:       - Type:            DATA
-; THREADS-NEXT:    Segments:
-; THREADS-NEXT:      - SectionOffset:   3
-; THREADS-NEXT:        InitFlags:       1
-; THREADS-NEXT:        Content:         48656C6C6F2100

llvm/test/MC/WebAssembly/reloc-data.ll

-; RUN: llc -O0 -filetype=obj -thread-model=single %s -o - | llvm-readobj -r -expand-relocs | FileCheck %s
+; RUN: llc -O0 -filetype=obj %s -o - | llvm-readobj -r -expand-relocs | FileCheck %s
 
 target triple = "wasm32-unknown-unknown"
 
 ; foo and bar are external and internal symbols.  a and b are pointers
 ; initialized to these locations offset by 2 and -2 elements respecitively.
 
 @foo = external global i32, align 4
 @bar = global i64 7, align 4

llvm/test/MC/WebAssembly/unnamed-data.ll

-; RUN: llc -filetype=obj -thread-model=single %s -o - | obj2yaml | FileCheck %s
+; RUN: llc -filetype=obj %s -o - | obj2yaml | FileCheck %s
 
 target triple = "wasm32-unknown-unknown"
 
 @.str1 = private unnamed_addr constant [6 x i8] c"hello\00", align 1
 @.str2 = private unnamed_addr constant [6 x i8] c"world\00", align 1
 
 @a = global i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str1, i32 0, i32 0), align 8
 @b = global i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str2, i32 0, i32 0), align 8

llvm/test/MC/WebAssembly/weak-alias.ll

-; RUN: llc -filetype=obj -thread-model=single -wasm-keep-registers %s -o %t.o
+; RUN: llc -filetype=obj -wasm-keep-registers %s -o %t.o
 ; RUN: obj2yaml %t.o | FileCheck %s
 ; RUN: llvm-objdump -t %t.o | FileCheck --check-prefix=CHECK-SYMS %s
 
 target triple = "wasm32-unknown-unknown"
 
 ; 'foo_alias()' is weak alias of function 'foo()'
 ; 'bar_alias' is weak alias of global variable 'bar'
 ; Generates two exports of the same function, one of them weak

llvm/test/tools/llvm-nm/wasm/local-symbols.ll

-; RUN: llc -filetype=obj -thread-model=single -mtriple=wasm32-unknown-unknown -o %t.o %s
+; RUN: llc -filetype=obj -mtriple=wasm32-unknown-unknown -o %t.o %s
 ; RUN: llvm-nm %t.o | FileCheck %s
 
 @foo = internal global i32 1, align 4
 @bar = global i32 1, align 4
 
 ; CHECK: 00000004 D bar
 ; CHECK: 00000000 d foo

llvm/test/tools/llvm-objdump/WebAssembly/relocations.test

-; RUN: llc -thread-model=single -mtriple=wasm32-unknown-unknown -filetype=obj %s -o - | llvm-objdump -r - | FileCheck %s
+; RUN: llc -mtriple=wasm32-unknown-unknown -filetype=obj %s -o - | llvm-objdump -r - | FileCheck %s
 
 @foo = external global i32, align 4
 @bar = global i32* @foo, align 4
 
 define void @make_call(void ()* nocapture %func) {
 entry:
   call void %func()
   ret void
 }
 
 ; CHECK:      RELOCATION RECORDS FOR [CODE]:
 ; CHECK-NEXT: 00000006 R_WASM_TYPE_INDEX_LEB 1+0
 
 ; CHECK:      RELOCATION RECORDS FOR [DATA]:
 ; CHECK-NEXT: 00000006 R_WASM_MEMORY_ADDR_I32 foo+0