[WebAssembly] Enable nontrapping-fptoint and bulk-memory by default. (l…

…lvm#112049)

We were prepared to enable these features [back in February], but they
got pulled for what appear to be unrelated reasons. So let's have
another try at enabling them!

Another motivation here is that it'd be convenient for the [Lime1
proposal] if "lime1" is close to a subset of "generic" (missing only
for extended-const).

[back in February]:
WebAssembly/tool-conventions#158 (comment)
[Lime1 proposal]: llvm#112035

clang/docs/ReleaseNotes.rst

@@ -690,6 +690,15 @@ NetBSD Support
 WebAssembly Support
 ^^^^^^^^^^^^^^^^^^^
 
+The default target CPU, "generic", now enables the `-mnontrapping-fptoint`
+and `-mbulk-memory` flags, which correspond to the [Bulk Memory Operations]
+and [Non-trapping float-to-int Conversions] language features, which are
+[widely implemented in engines].
+
+[Bulk Memory Operations]: https://github.com/WebAssembly/bulk-memory-operations/blob/master/proposals/bulk-memory-operations/Overview.md
+[Non-trapping float-to-int Conversions]: https://github.com/WebAssembly/spec/blob/master/proposals/nontrapping-float-to-int-conversion/Overview.md
+[widely implemented in engines]: https://webassembly.org/features/
+
 AVR Support
 ^^^^^^^^^^^
 

clang/lib/Basic/Targets/WebAssembly.cpp

@@ -154,20 +154,20 @@ bool WebAssemblyTargetInfo::initFeatureMap(
     llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags, StringRef CPU,
     const std::vector<std::string> &FeaturesVec) const {
   auto addGenericFeatures = [&]() {
+    Features["bulk-memory"] = true;
     Features["multivalue"] = true;
     Features["mutable-globals"] = true;
+    Features["nontrapping-fptoint"] = true;
     Features["reference-types"] = true;
     Features["sign-ext"] = true;
   };
   auto addBleedingEdgeFeatures = [&]() {
     addGenericFeatures();
     Features["atomics"] = true;
-    Features["bulk-memory"] = true;
     Features["exception-handling"] = true;
     Features["extended-const"] = true;
     Features["fp16"] = true;
     Features["multimemory"] = true;
-    Features["nontrapping-fptoint"] = true;
     Features["tail-call"] = true;
     Features["wide-arithmetic"] = true;
     setSIMDLevel(Features, RelaxedSIMD, true);

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

@@ -163,8 +163,10 @@
 // RUN:     -target wasm64-unknown-unknown -mcpu=generic \
 // RUN:   | FileCheck %s -check-prefix=GENERIC-INCLUDE
 //
+// GENERIC-INCLUDE-DAG: #define __wasm_bulk_memory__ 1{{$}}
 // GENERIC-INCLUDE-DAG: #define __wasm_multivalue__ 1{{$}}
 // GENERIC-INCLUDE-DAG: #define __wasm_mutable_globals__ 1{{$}}
+// GENERIC-INCLUDE-DAG: #define __wasm_nontrapping_fptoint__ 1{{$}}
 // GENERIC-INCLUDE-DAG: #define __wasm_reference_types__ 1{{$}}
 // GENERIC-INCLUDE-DAG: #define __wasm_sign_ext__ 1{{$}}
 //
@@ -176,12 +178,10 @@
 // RUN:   | FileCheck %s -check-prefix=GENERIC
 //
 // GENERIC-NOT: #define __wasm_atomics__ 1{{$}}
-// GENERIC-NOT: #define __wasm_bulk_memory__ 1{{$}}
 // GENERIC-NOT: #define __wasm_exception_handling__ 1{{$}}
 // GENERIC-NOT: #define __wasm_extended_const__ 1{{$}}
 // GENERIC-NOT: #define __wasm__fp16__ 1{{$}}
 // GENERIC-NOT: #define __wasm_multimemory__ 1{{$}}
-// GENERIC-NOT: #define __wasm_nontrapping_fptoint__ 1{{$}}
 // GENERIC-NOT: #define __wasm_relaxed_simd__ 1{{$}}
 // GENERIC-NOT: #define __wasm_simd128__ 1{{$}}
 // GENERIC-NOT: #define __wasm_tail_call__ 1{{$}}

lld/test/wasm/custom-section-name.ll

@@ -1,4 +1,4 @@
-; RUN: llc -filetype=obj %s -o %t.o
+; RUN: llc -filetype=obj -mattr=-bulk-memory %s -o %t.o
 ; RUN: wasm-ld -no-gc-sections --no-entry -o %t.wasm %t.o
 ; RUN: obj2yaml %t.wasm | FileCheck %s --check-prefixes=CHECK,NO-BSS
 ; RUN: wasm-ld -no-gc-sections --no-entry --import-memory -o %t.bss.wasm %t.o

lld/test/wasm/data-segments.ll

@@ -1,4 +1,4 @@
-; RUN: llc --mtriple=wasm32-unknown-unknown -filetype=obj %s -o %t.atomics.o -mattr=+atomics
+; RUN: llc --mtriple=wasm32-unknown-unknown -filetype=obj %s -o %t.atomics.o -mattr=+atomics,-bulk-memory
 ; RUN: llc --mtriple=wasm32-unknown-unknown -filetype=obj %s -o %t.bulk-mem.o -mattr=+bulk-memory
 ; RUN: llc --mtriple=wasm64-unknown-unknown -filetype=obj %s -o %t.bulk-mem64.o -mattr=+bulk-memory
 ; RUN: llc --mtriple=wasm32-unknown-unknown -filetype=obj %s -o %t.atomics.bulk-mem.o -mattr=+atomics,+bulk-memory

lld/test/wasm/lto/Inputs/libcall-archive.ll

@@ -1,6 +1,8 @@
 target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20"
 target triple = "wasm32-unknown-unknown"
 
-define void @memcpy() {
+define void @memcpy() #0 {
   ret void
 }
+
+attributes #0 = { "target-features"="-bulk-memory" }

lld/test/wasm/lto/libcall-archive.ll

@@ -8,14 +8,16 @@
 target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20"
 target triple = "wasm32-unknown-unknown"
 
-define void @_start(ptr %a, ptr %b) {
+define void @_start(ptr %a, ptr %b) #0 {
 entry:
   call void @llvm.memcpy.p0.p0.i64(ptr %a, ptr %b, i64 1024, i1 false)
   ret void
 }
 
 declare void @llvm.memcpy.p0.p0.i64(ptr nocapture, ptr nocapture, i64, i1)
 
+attributes #0 = { "target-features"="-bulk-memory" }
+
 ; CHECK:       - Type:            CUSTOM
 ; CHECK-NEXT:    Name:            name
 ; CHECK-NEXT:    FunctionNames:

lld/test/wasm/lto/stub-library-libcall.s

@@ -2,7 +2,7 @@
 # RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown -o %t_main.o %t/main.s
 # RUN: llvm-as %S/Inputs/foo.ll -o %t_foo.o
 # RUN: llvm-as %S/Inputs/libcall.ll -o %t_libcall.o
-# RUN: wasm-ld %t_main.o %t_libcall.o %t_foo.o %p/Inputs/stub.so -o %t.wasm
+# RUN: wasm-ld -mllvm -mattr=-bulk-memory %t_main.o %t_libcall.o %t_foo.o %p/Inputs/stub.so -o %t.wasm
 # RUN: obj2yaml %t.wasm | FileCheck %s
 
 # The function `func_with_libcall` will generate an undefined reference to
@@ -12,7 +12,7 @@
 # If %t_foo.o is not included in the link we get an undefined symbol reported
 # to the dependency of memcpy on the foo export:
 
-# RUN: not wasm-ld %t_main.o %t_libcall.o %p/Inputs/stub.so -o %t.wasm 2>&1 | FileCheck --check-prefix=MISSING %s
+# RUN: not wasm-ld -mllvm -mattr=-bulk-memory %t_main.o %t_libcall.o %p/Inputs/stub.so -o %t.wasm 2>&1 | FileCheck --check-prefix=MISSING %s
 # MISSING: stub.so: undefined symbol: foo. Required by memcpy
 
 #--- main.s

llvm/docs/ReleaseNotes.md

@@ -180,6 +180,15 @@ Changes to the RISC-V Backend
 Changes to the WebAssembly Backend
 ----------------------------------
 
+The default target CPU, "generic", now enables the `-mnontrapping-fptoint`
+and `-mbulk-memory` flags, which correspond to the [Bulk Memory Operations]
+and [Non-trapping float-to-int Conversions] language features, which are
+[widely implemented in engines].
+
+[Bulk Memory Operations]: https://github.com/WebAssembly/bulk-memory-operations/blob/master/proposals/bulk-memory-operations/Overview.md
+[Non-trapping float-to-int Conversions]: https://github.com/WebAssembly/spec/blob/master/proposals/nontrapping-float-to-int-conversion/Overview.md
+[widely implemented in engines]: https://webassembly.org/features/
+
 Changes to the Windows Target
 -----------------------------
 

llvm/lib/Target/WebAssembly/WebAssembly.td

@@ -114,7 +114,8 @@ def : ProcessorModel<"mvp", NoSchedModel, []>;
 // consideration given to available support in relevant engines and tools, and
 // the importance of the features.
 def : ProcessorModel<"generic", NoSchedModel,
-                      [FeatureMultivalue, FeatureMutableGlobals,
+                      [FeatureBulkMemory, FeatureMultivalue,
+                       FeatureMutableGlobals, FeatureNontrappingFPToInt,
                        FeatureReferenceTypes, FeatureSignExt]>;
 
 // Latest and greatest experimental version of WebAssembly. Bugs included!

llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp

@@ -111,6 +111,7 @@ static Function *createWrapper(Function *F, FunctionType *Ty) {
 
   Function *Wrapper = Function::Create(Ty, Function::PrivateLinkage,
                                        F->getName() + "_bitcast", M);
+  Wrapper->setAttributes(F->getAttributes());
   BasicBlock *BB = BasicBlock::Create(M->getContext(), "body", Wrapper);
   const DataLayout &DL = BB->getDataLayout();
 
@@ -201,6 +202,7 @@ static Function *createWrapper(Function *F, FunctionType *Ty) {
     Wrapper->eraseFromParent();
     Wrapper = Function::Create(Ty, Function::PrivateLinkage,
                                F->getName() + "_bitcast_invalid", M);
+    Wrapper->setAttributes(F->getAttributes());
     BasicBlock *BB = BasicBlock::Create(M->getContext(), "body", Wrapper);
     new UnreachableInst(M->getContext(), BB);
     Wrapper->setName(F->getName() + "_bitcast_invalid");

llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp

@@ -233,13 +233,30 @@ class CoalesceFeaturesAndStripAtomics final : public ModulePass {
 
 private:
   FeatureBitset coalesceFeatures(const Module &M) {
-    FeatureBitset Features =
-        WasmTM
-            ->getSubtargetImpl(std::string(WasmTM->getTargetCPU()),
-                               std::string(WasmTM->getTargetFeatureString()))
-            ->getFeatureBits();
-    for (auto &F : M)
+    // Union the features of all defined functions. Start with an empty set, so
+    // that if a feature is disabled in every function, we'll compute it as
+    // disabled. If any function lacks a target-features attribute, it'll
+    // default to the target CPU from the `TargetMachine`.
+    FeatureBitset Features;
+    bool AnyDefinedFuncs = false;
+    for (auto &F : M) {
+      if (F.isDeclaration())
+        continue;
+
       Features |= WasmTM->getSubtargetImpl(F)->getFeatureBits();
+      AnyDefinedFuncs = true;
+    }
+
+    // If we have no defined functions, use the target CPU from the
+    // `TargetMachine`.
+    if (!AnyDefinedFuncs) {
+      Features =
+          WasmTM
+              ->getSubtargetImpl(std::string(WasmTM->getTargetCPU()),
+                                 std::string(WasmTM->getTargetFeatureString()))
+              ->getFeatureBits();
+    }
+
     return Features;
   }
 

llvm/test/CodeGen/WebAssembly/cfg-stackify-eh-legacy.ll

@@ -1,9 +1,9 @@
 ; REQUIRES: asserts
-; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling | FileCheck %s
-; RUN: llc < %s -disable-wasm-fallthrough-return-opt -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling
-; RUN: llc < %s -O0 -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -verify-machineinstrs -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling | FileCheck %s --check-prefix=NOOPT
-; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling -wasm-disable-ehpad-sort -stats 2>&1 | FileCheck %s --check-prefix=NOSORT
-; RUN: llc < %s -disable-wasm-fallthrough-return-opt -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling -wasm-disable-ehpad-sort | FileCheck %s --check-prefix=NOSORT-LOCALS
+; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling,bulk-memory | FileCheck %s
+; RUN: llc < %s -disable-wasm-fallthrough-return-opt -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling,bulk-memory
+; RUN: llc < %s -O0 -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -verify-machineinstrs -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling,-bulk-memory | FileCheck %s --check-prefix=NOOPT
+; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling,-bulk-memory -wasm-disable-ehpad-sort -stats 2>&1 | FileCheck %s --check-prefix=NOSORT
+; RUN: llc < %s -disable-wasm-fallthrough-return-opt -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling,-bulk-memory -wasm-disable-ehpad-sort | FileCheck %s --check-prefix=NOSORT-LOCALS
 
 target triple = "wasm32-unknown-unknown"
 

llvm/test/CodeGen/WebAssembly/target-features-cpus.ll

@@ -13,14 +13,20 @@ target triple = "wasm32-unknown-unknown"
 
 ; generic: +multivalue, +mutable-globals, +reference-types, +sign-ext
 ; GENERIC-LABEL: .custom_section.target_features,"",@
-; GENERIC-NEXT: .int8  4
+; GENERIC-NEXT: .int8  6
+; GENERIC-NEXT: .int8  43
+; GENERIC-NEXT: .int8  11
+; GENERIC-NEXT: .ascii  "bulk-memory"
 ; GENERIC-NEXT: .int8  43
 ; GENERIC-NEXT: .int8  10
 ; GENERIC-NEXT: .ascii  "multivalue"
 ; GENERIC-NEXT: .int8  43
 ; GENERIC-NEXT: .int8  15
 ; GENERIC-NEXT: .ascii  "mutable-globals"
 ; GENERIC-NEXT: .int8  43
+; GENERIC-NEXT: .int8  19
+; GENERIC-NEXT: .ascii  "nontrapping-fptoint"
+; GENERIC-NEXT: .int8  43
 ; GENERIC-NEXT: .int8  15
 ; GENERIC-NEXT: .ascii  "reference-types"
 ; GENERIC-NEXT: .int8  43

llvm/test/MC/WebAssembly/extern-functype-intrinsic.ll

@@ -1,5 +1,5 @@
-; RUN: llc %s -o - | FileCheck %s
-; RUN: llc %s -o - | llvm-mc -triple=wasm32-unknown-unknown | FileCheck %s
+; RUN: llc %s -mattr=-bulk-memory -o - | FileCheck %s
+; RUN: llc %s -mattr=-bulk-memory -o - | llvm-mc -triple=wasm32-unknown-unknown | FileCheck %s
 
 ; ModuleID = 'test.c'
 source_filename = "test.c"

llvm/test/MC/WebAssembly/libcall.ll

@@ -1,4 +1,4 @@
-; RUN: llc -filetype=obj %s -o - | obj2yaml | FileCheck %s
+; RUN: llc -filetype=obj -mattr=-bulk-memory %s -o - | obj2yaml | FileCheck %s
 
 target triple = "wasm32-unknown-unknown"