From 2b8ad6b6040833f4f8702721ebaa7749e5c23e60 Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper@intel.com>
Date: Wed, 12 Aug 2020 11:35:08 -0700
Subject: [PATCH] [WebAssembly] Don't depend on the flags set by
 handleTargetFeatures in initFeatureMap.

Properly set "simd128" in the feature map when "unimplemented-simd128"
is requested.

initFeatureMap is used to create the feature vector used by
handleTargetFeatures. There are later calls to initFeatureMap in
CodeGen that were using these flags to recreate the map. But the
original feature vector should be passed to those calls. So that
should be enough to rebuild the map.

The only issue seemed to be that simd128 was not enabled in the
map by the first call to initFeatureMap. Using the SIMDLevel set
by handleTargetFeatures in the later calls allowed simd128 to be
set in the later versions of the map.

To fix this I've added an override of setFeatureEnabled that
will update the map the first time with the correct simd dependency.

Differential Revision: https://reviews.llvm.org/D85806
---
 clang/lib/Basic/Targets/WebAssembly.cpp | 62 +++++++++++++------------
 clang/lib/Basic/Targets/WebAssembly.h   |  6 ++-
 2 files changed, 37 insertions(+), 31 deletions(-)

diff --git a/clang/lib/Basic/Targets/WebAssembly.cpp b/clang/lib/Basic/Targets/WebAssembly.cpp
index 6746768090f5..dcb3d8fd7790 100644
--- a/clang/lib/Basic/Targets/WebAssembly.cpp
+++ b/clang/lib/Basic/Targets/WebAssembly.cpp
@@ -96,19 +96,43 @@ void WebAssemblyTargetInfo::getTargetDefines(const LangOptions &Opts,
 }
 
 void WebAssemblyTargetInfo::setSIMDLevel(llvm::StringMap<bool> &Features,
-                                         SIMDEnum Level) {
+                                         SIMDEnum Level, bool Enabled) {
+  if (Enabled) {
+    switch (Level) {
+    case UnimplementedSIMD128:
+      Features["unimplemented-simd128"] = true;
+      LLVM_FALLTHROUGH;
+    case SIMD128:
+      Features["simd128"] = true;
+      LLVM_FALLTHROUGH;
+    case NoSIMD:
+      break;
+    }
+    return;
+  }
+
   switch (Level) {
-  case UnimplementedSIMD128:
-    Features["unimplemented-simd128"] = true;
-    LLVM_FALLTHROUGH;
-  case SIMD128:
-    Features["simd128"] = true;
-    LLVM_FALLTHROUGH;
   case NoSIMD:
+  case SIMD128:
+    Features["simd128"] = false;
+    LLVM_FALLTHROUGH;
+  case UnimplementedSIMD128:
+    Features["unimplemented-simd128"] = false;
     break;
   }
 }
 
+void WebAssemblyTargetInfo::setFeatureEnabled(llvm::StringMap<bool> &Features,
+                                              StringRef Name,
+                                              bool Enabled) const {
+  if (Name == "simd128")
+    setSIMDLevel(Features, SIMD128, Enabled);
+  else if (Name == "unimplemented-simd128")
+    setSIMDLevel(Features, UnimplementedSIMD128, Enabled);
+  else
+    Features[Name] = Enabled;
+}
+
 bool WebAssemblyTargetInfo::initFeatureMap(
     llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags, StringRef CPU,
     const std::vector<std::string> &FeaturesVec) const {
@@ -119,30 +143,8 @@ bool WebAssemblyTargetInfo::initFeatureMap(
     Features["atomics"] = true;
     Features["mutable-globals"] = true;
     Features["tail-call"] = true;
-    setSIMDLevel(Features, SIMD128);
+    setSIMDLevel(Features, SIMD128, true);
   }
-  // Other targets do not consider user-configured features here, but while we
-  // are actively developing new features it is useful to let user-configured
-  // features control availability of builtins
-  setSIMDLevel(Features, SIMDLevel);
-  if (HasNontrappingFPToInt)
-    Features["nontrapping-fptoint"] = true;
-  if (HasSignExt)
-    Features["sign-ext"] = true;
-  if (HasExceptionHandling)
-    Features["exception-handling"] = true;
-  if (HasBulkMemory)
-    Features["bulk-memory"] = true;
-  if (HasAtomics)
-    Features["atomics"] = true;
-  if (HasMutableGlobals)
-    Features["mutable-globals"] = true;
-  if (HasMultivalue)
-    Features["multivalue"] = true;
-  if (HasTailCall)
-    Features["tail-call"] = true;
-  if (HasReferenceTypes)
-    Features["reference-types"] = true;
 
   return TargetInfo::initFeatureMap(Features, Diags, CPU, FeaturesVec);
 }
diff --git a/clang/lib/Basic/Targets/WebAssembly.h b/clang/lib/Basic/Targets/WebAssembly.h
index 77a2fe9ae117..0068ccb5d71f 100644
--- a/clang/lib/Basic/Targets/WebAssembly.h
+++ b/clang/lib/Basic/Targets/WebAssembly.h
@@ -69,7 +69,8 @@ protected:
                         MacroBuilder &Builder) const override;
 
 private:
-  static void setSIMDLevel(llvm::StringMap<bool> &Features, SIMDEnum Level);
+  static void setSIMDLevel(llvm::StringMap<bool> &Features, SIMDEnum Level,
+                           bool Enabled);
 
   bool
   initFeatureMap(llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags,
@@ -77,6 +78,9 @@ private:
                  const std::vector<std::string> &FeaturesVec) const override;
   bool hasFeature(StringRef Feature) const final;
 
+  void setFeatureEnabled(llvm::StringMap<bool> &Features, StringRef Name,
+                         bool Enabled) const final;
+
   bool handleTargetFeatures(std::vector<std::string> &Features,
                             DiagnosticsEngine &Diags) final;