r363346 - [Targets] Move soft-float-abi filtering to `initFeatureMap`

[George Burgess IV via cfe-commits]

Author: gbiv
Date: Thu Jun 13 17:35:17 2019
New Revision: 363346

URL: http://llvm.org/viewvc/llvm-project?rev=363346&view=rev
Log:
[Targets] Move soft-float-abi filtering to `initFeatureMap`

ARM has a special target feature called soft-float-abi. This feature is
special, since we get it passed to us explicitly in the frontend, but
filter it out before it can land in any target feature strings in LLVM
IR.

__attribute__((target(""))) doesn't quite filter these features out
properly, so today, we get warnings about soft-float-abi being an
unknown feature from the backend.

This CL has us filter soft-float-abi out at a slightly different point,
so we don't end up passing these invalid features to the backend.

Differential Revision: https://reviews.llvm.org/D61750

Added:
    cfe/trunk/test/CodeGen/arm-soft-float-abi-filtering.c
Modified:
    cfe/trunk/lib/Basic/Targets/ARM.cpp
    cfe/trunk/lib/Basic/Targets/ARM.h

Modified: cfe/trunk/lib/Basic/Targets/ARM.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Targets/ARM.cpp?rev=363346&r1=363345&r2=363346&view=diff
==============================================================================
--- cfe/trunk/lib/Basic/Targets/ARM.cpp (original)
+++ cfe/trunk/lib/Basic/Targets/ARM.cpp Thu Jun 13 17:35:17 2019
@@ -323,6 +323,8 @@ ARMTargetInfo::ARMTargetInfo(const llvm:
     this->MCountName = Opts.EABIVersion == llvm::EABI::GNU
                            ? "\01__gnu_mcount_nc"
                            : "\01mcount";
+
+  SoftFloatABI = llvm::is_contained(Opts.FeaturesAsWritten, "+soft-float-abi");
 }
 
 StringRef ARMTargetInfo::getABI() const { return ABI; }
@@ -385,12 +387,21 @@ bool ARMTargetInfo::initFeatureMap(
 
   // Convert user-provided arm and thumb GNU target attributes to
   // [-|+]thumb-mode target features respectively.
-  std::vector<std::string> UpdatedFeaturesVec(FeaturesVec);
-  for (auto &Feature : UpdatedFeaturesVec) {
-    if (Feature.compare("+arm") == 0)
-      Feature = "-thumb-mode";
-    else if (Feature.compare("+thumb") == 0)
-      Feature = "+thumb-mode";
+  std::vector<std::string> UpdatedFeaturesVec;
+  for (const auto &Feature : FeaturesVec) {
+    // Skip soft-float-abi; it's something we only use to initialize a bit of
+    // class state, and is otherwise unrecognized.
+    if (Feature == "+soft-float-abi")
+      continue;
+
+    StringRef FixedFeature;
+    if (Feature == "+arm")
+      FixedFeature = "-thumb-mode";
+    else if (Feature == "+thumb")
+      FixedFeature = "+thumb-mode";
+    else
+      FixedFeature = Feature;
+    UpdatedFeaturesVec.push_back(FixedFeature.str());
   }
 
   return TargetInfo::initFeatureMap(Features, Diags, CPU, UpdatedFeaturesVec);
@@ -405,7 +416,8 @@ bool ARMTargetInfo::handleTargetFeatures
   Crypto = 0;
   DSP = 0;
   Unaligned = 1;
-  SoftFloat = SoftFloatABI = false;
+  SoftFloat = false;
+  // Note that SoftFloatABI is initialized in our constructor.
   HWDiv = 0;
   DotProd = 0;
   HasFloat16 = true;
@@ -415,8 +427,6 @@ bool ARMTargetInfo::handleTargetFeatures
   for (const auto &Feature : Features) {
     if (Feature == "+soft-float") {
       SoftFloat = true;
-    } else if (Feature == "+soft-float-abi") {
-      SoftFloatABI = true;
     } else if (Feature == "+vfp2sp" || Feature == "+vfp2d16sp" ||
                Feature == "+vfp2" || Feature == "+vfp2d16") {
       FPU |= VFP2FPU;
@@ -510,11 +520,6 @@ bool ARMTargetInfo::handleTargetFeatures
   else if (FPMath == FP_VFP)
     Features.push_back("-neonfp");
 
-  // Remove front-end specific options which the backend handles differently.
-  auto Feature = llvm::find(Features, "+soft-float-abi");
-  if (Feature != Features.end())
-    Features.erase(Feature);
-
   return true;
 }
 

Modified: cfe/trunk/lib/Basic/Targets/ARM.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Targets/ARM.h?rev=363346&r1=363345&r2=363346&view=diff
==============================================================================
--- cfe/trunk/lib/Basic/Targets/ARM.h (original)
+++ cfe/trunk/lib/Basic/Targets/ARM.h Thu Jun 13 17:35:17 2019
@@ -124,6 +124,12 @@ public:
                  StringRef CPU,
                  const std::vector<std::string> &FeaturesVec) const override;
 
+  bool isValidFeatureName(StringRef Feature) const override {
+    // We pass soft-float-abi in as a -target-feature, but the backend figures
+    // this out through other means.
+    return Feature != "soft-float-abi";
+  }
+
   bool handleTargetFeatures(std::vector<std::string> &Features,
                             DiagnosticsEngine &Diags) override;
 

Added: cfe/trunk/test/CodeGen/arm-soft-float-abi-filtering.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/arm-soft-float-abi-filtering.c?rev=363346&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/arm-soft-float-abi-filtering.c (added)
+++ cfe/trunk/test/CodeGen/arm-soft-float-abi-filtering.c Thu Jun 13 17:35:17 2019
@@ -0,0 +1,9 @@
+// REQUIRES: arm-registered-target
+// RUN: %clang_cc1 -emit-llvm -o - -triple arm-none-linux-gnueabi -target-feature "+soft-float-abi" %s | FileCheck %s
+// RUN: %clang_cc1 -verify -triple arm-none-linux-gnueabi -target-feature "+soft-float-abi" %s
+
+// CHECK-NOT: +soft-float-abi
+
+void foo() {}
+__attribute__((target("crc"))) void bar() {}
+__attribute__((target("soft-float-abi"))) void baz() {} // expected-warning{{unsupported 'soft-float-abi' in the 'target' attribute string}}