[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

llvm-svn: 355112

1 files changed, 13 insertions, 8 deletions

diff --git a/clang/test/Driver/wasm-toolchain.c b/clang/test/Driver/wasm-toolchain.c
index 22867117ffd..bdef316c85c 100644
--- a/clang/test/Driver/wasm-toolchain.c
+++ b/clang/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'