[WebAssembly] Check bulk-memory when adjusting lang opts

We previously had logic to disable pthreads, set the ThreadModel to Single, and
disable thread-safe statics when the atomics target features is disabled, since
that means that the resulting program will not be used in a threaded context.
Similarly check for the presence of the bulk-memory feature, since that is also
necessary to produce multithreaded programs.

Differential Revision: https://reviews.llvm.org/D121014

Author: tlively

clang/lib/Basic/Targets/WebAssembly.cpp

@@ -256,9 +256,10 @@ ArrayRef<Builtin::Info> WebAssemblyTargetInfo::getTargetBuiltins() const {
 void WebAssemblyTargetInfo::adjust(DiagnosticsEngine &Diags,
                                    LangOptions &Opts) {
   TargetInfo::adjust(Diags, Opts);
-  // If the Atomics feature isn't available, turn off POSIXThreads and
-  // ThreadModel, so that we don't predefine _REENTRANT or __STDCPP_THREADS__.
-  if (!HasAtomics) {
+  // Turn off POSIXThreads and ThreadModel so that we don't predefine _REENTRANT
+  // or __STDCPP_THREADS__ if we will eventually end up stripping atomics
+  // because they are unsupported.
+  if (!HasAtomics || !HasBulkMemory) {
     Opts.POSIXThreads = false;
     Opts.setThreadModel(LangOptions::ThreadModelKind::Single);
     Opts.ThreadsafeStatics = false;

clang/test/CodeGenCXX/static-init-wasm.cpp

@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -emit-llvm -triple=wasm32-unknown-unknown -target-feature +atomics -o - %s \
+// RUN: %clang_cc1 -emit-llvm -triple=wasm32-unknown-unknown -target-feature +atomics -target-feature +bulk-memory -o - %s \
 // RUN:   | FileCheck %s -check-prefix=WEBASSEMBLY32
-// RUN: %clang_cc1 -emit-llvm -triple=wasm64-unknown-unknown -target-feature +atomics -o - %s \
+// RUN: %clang_cc1 -emit-llvm -triple=wasm64-unknown-unknown -target-feature +atomics -target-feature +bulk-memory -o - %s \
 // RUN:   | FileCheck %s -check-prefix=WEBASSEMBLY64
 
 // Test that we don't create common blocks.
@@ -53,9 +53,9 @@ A theA;
 // WEBASSEMBLY64: define internal void @_GLOBAL__sub_I_static_init_wasm.cpp() #3 {
 // WEBASSEMBLY64: call void @__cxx_global_var_init()
 
-// RUN: %clang_cc1 -emit-llvm -triple=wasm32-unknown-unknown -o - %s \
+// RUN: %clang_cc1 -emit-llvm -triple=wasm32-unknown-unknown -target-feature +bulk-memory -o - %s \
 // RUN:   | FileCheck %s -check-prefix=NOATOMICS
-// RUN: %clang_cc1 -emit-llvm -triple=wasm64-unknown-unknown -o - %s \
+// RUN: %clang_cc1 -emit-llvm -triple=wasm64-unknown-unknown -target-feature +bulk-memory -o - %s \
 // RUN:   | FileCheck %s -check-prefix=NOATOMICS
 
 // NOATOMICS-LABEL: @_Z1gv()
@@ -66,3 +66,17 @@ A theA;
 // NOATOMICS-NOT:   __cxa_guard_acquire
 // NOATOMICS:       [[END]]:
 // NOATOMICS-NEXT:  ret void
+
+// RUN: %clang_cc1 -emit-llvm -triple=wasm32-unknown-unknown -target-feature +atomics -o - %s \
+// RUN:   | FileCheck %s -check-prefix=NOBULKMEM
+// RUN: %clang_cc1 -emit-llvm -triple=wasm64-unknown-unknown -target-feature +atomics -o - %s \
+// RUN:   | FileCheck %s -check-prefix=NOBULKMEM
+
+// NOBULKMEM-LABEL: @_Z1gv()
+// NOBULKMEM:       %[[R0:.+]] = load i8, i8* @_ZGVZ1gvE1a, align 1
+// NOBULKMEM-NEXT:  %guard.uninitialized = icmp eq i8 %[[R0]], 0
+// NOBULKMEM-NEXT:  br i1 %guard.uninitialized, label %[[CHECK:.+]], label %[[END:.+]],
+// NOBULKMEM:       [[CHECK]]:
+// NOBULKMEM-NOT:   __cxa_guard_acquire
+// NOBULKMEM:       [[END]]:
+// NOBULKMEM-NEXT:  ret void