[WebAssembly] Remove uses of ThreadModel

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.

Reviewers: aheejin, sbc100, dschuff

Subscribers: mehdi_amini, jgravelle-google, hiraditya, sunfish, steven_wu, dexonsmith, rupprecht, jfb, jdoerfert, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D58742

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@355112 91177308-0d34-0410-b5e6-96231b3b80d8

8 files changed, 68 insertions, 66 deletions

diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index dd597550d2..8a68e68a2d 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -2160,6 +2160,8 @@ 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>;
 
diff --git a/include/clang/Driver/ToolChain.h b/include/clang/Driver/ToolChain.h
index e82675d334..eec49ec3dd 100644
--- a/include/clang/Driver/ToolChain.h
+++ b/include/clang/Driver/ToolChain.h
@@ -453,9 +453,7 @@ public:
   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;
diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index b405390d44..eb03e6e87c 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -1528,7 +1528,7 @@ void Driver::PrintVersion(const Compilation &C, raw_ostream &OS) const {
     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.
diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp
index e7fb3fe403..ff48360b66 100644
--- a/lib/Driver/ToolChains/Clang.cpp
+++ b/lib/Driver/ToolChains/Clang.cpp
@@ -3830,7 +3830,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     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);
 
diff --git a/lib/Driver/ToolChains/WebAssembly.cpp b/lib/Driver/ToolChains/WebAssembly.cpp
index f076b528ce..ce28d447ff 100644
--- a/lib/Driver/ToolChains/WebAssembly.cpp
+++ b/lib/Driver/ToolChains/WebAssembly.cpp
@@ -20,27 +20,6 @@ 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) {}
 
@@ -145,15 +124,36 @@ void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
                          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");
   }
 }
 
@@ -212,17 +212,6 @@ void WebAssembly::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
   }
 }
 
-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);
 }
diff --git a/lib/Driver/ToolChains/WebAssembly.h b/lib/Driver/ToolChains/WebAssembly.h
index 6ededd84ec..2d9210ac04 100644
--- a/lib/Driver/ToolChains/WebAssembly.h
+++ b/lib/Driver/ToolChains/WebAssembly.h
@@ -64,7 +64,6 @@ private:
       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"; }
 
diff --git a/test/Driver/wasm-toolchain.c b/test/Driver/wasm-toolchain.c
index 22867117ff..bdef316c85 100644
--- a/test/Driver/wasm-toolchain.c
+++ b/test/Driver/wasm-toolchain.c
@@ -40,14 +40,19 @@
 // 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"
+
+// '-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'
 
-// 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'
+// '-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'
diff --git a/test/Preprocessor/wasm-target-features.c b/test/Preprocessor/wasm-target-features.c
index 3ab22500c1..80e299247c 100644
--- a/test/Preprocessor/wasm-target-features.c
+++ b/test/Preprocessor/wasm-target-features.c
@@ -6,7 +6,7 @@
 // RUN:   | FileCheck %s -check-prefix=SIMD128
 //
 // SIMD128:#define __wasm_simd128__ 1{{$}}
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -munimplemented-simd128 \
 // RUN:   | FileCheck %s -check-prefix=SIMD128-UNIMPLEMENTED
@@ -15,7 +15,7 @@
 // RUN:   | FileCheck %s -check-prefix=SIMD128-UNIMPLEMENTED
 //
 // SIMD128-UNIMPLEMENTED:#define __wasm_unimplemented_simd128__ 1{{$}}
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mnontrapping-fptoint \
 // RUN:   | FileCheck %s -check-prefix=NONTRAPPING-FPTOINT
@@ -24,7 +24,7 @@
 // RUN:   | FileCheck %s -check-prefix=NONTRAPPING-FPTOINT
 //
 // NONTRAPPING-FPTOINT:#define __wasm_nontrapping_fptoint__ 1{{$}}
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -msign-ext \
 // RUN:   | FileCheck %s -check-prefix=SIGN-EXT
@@ -33,7 +33,7 @@
 // RUN:   | FileCheck %s -check-prefix=SIGN-EXT
 //
 // SIGN-EXT:#define __wasm_sign_ext__ 1{{$}}
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mexception-handling \
 // RUN:   | FileCheck %s -check-prefix=EXCEPTION-HANDLING
@@ -42,7 +42,7 @@
 // RUN:   | FileCheck %s -check-prefix=EXCEPTION-HANDLING
 //
 // EXCEPTION-HANDLING:#define __wasm_exception_handling__ 1{{$}}
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mbulk-memory \
 // RUN:   | FileCheck %s -check-prefix=BULK-MEMORY
@@ -51,18 +51,27 @@
 // RUN:   | FileCheck %s -check-prefix=BULK-MEMORY
 //
 // BULK-MEMORY:#define __wasm_bulk_memory__ 1{{$}}
-//
-// 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{{$}}
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=mvp \
 // RUN:   | FileCheck %s -check-prefix=MVP
@@ -77,7 +86,7 @@
 // MVP-NOT:#define __wasm_exception_handling__
 // MVP-NOT:#define __wasm_bulk_memory__
 // MVP-NOT:#define __wasm_atomics__
-//
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=bleeding-edge \
 // RUN:   | FileCheck %s -check-prefix=BLEEDING-EDGE
@@ -90,7 +99,7 @@
 // BLEEDING-EDGE-DAG:#define __wasm_simd128__ 1{{$}}
 // 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