Make march/target-cpu print a note with the list of valid values for ARM

When rejecting a march= or target-cpu command line parameter,
the message is quite lacking. This patch adds a note that prints
all possible values for the current target, if the target supports it.

This adds support for the ARM/AArch64 targets (more to come!). 

Differential Revision: https://reviews.llvm.org/D42978 

llvm-svn: 324673

clang/include/clang/Basic/DiagnosticCommonKinds.td

@@ -188,6 +188,7 @@ def note_invalid_subexpr_in_const_expr : Note<
 def err_target_unknown_triple : Error<
   "unknown target triple '%0', please use -triple or -arch">;
 def err_target_unknown_cpu : Error<"unknown target CPU '%0'">;
+def note_valid_options : Note<"valid target CPU values are: %0">;
 def err_target_unsupported_cpu_for_micromips : Error<
   "micromips is not supported for target CPU '%0'">;
 def err_target_unknown_abi : Error<"unknown target ABI '%0'">;

clang/include/clang/Basic/TargetInfo.h

@@ -867,6 +867,9 @@ public:
     return false;
   }
 
+  /// Fill a SmallVectorImpl with the valid values to setCPU.
+  virtual void fillValidCPUList(SmallVectorImpl<StringRef> &Values) const {}
+
   /// brief Determine whether this TargetInfo supports the given CPU name.
   virtual bool isValidCPUName(StringRef Name) const {
     return true;

clang/lib/Basic/Targets.cpp

@@ -38,6 +38,7 @@
 #include "Targets/X86.h"
 #include "Targets/XCore.h"
 #include "clang/Basic/Diagnostic.h"
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/Triple.h"
 
 using namespace clang;
@@ -607,6 +608,10 @@ TargetInfo::CreateTargetInfo(DiagnosticsEngine &Diags,
   // Set the target CPU if specified.
   if (!Opts->CPU.empty() && !Target->setCPU(Opts->CPU)) {
     Diags.Report(diag::err_target_unknown_cpu) << Opts->CPU;
+    SmallVector<StringRef, 32> ValidList;
+    Target->fillValidCPUList(ValidList);
+    if (!ValidList.empty())
+      Diags.Report(diag::note_valid_options) << llvm::join(ValidList, ", ");
     return nullptr;
   }
 

clang/lib/Basic/Targets/AArch64.cpp

@@ -101,6 +101,11 @@ bool AArch64TargetInfo::setCPU(const std::string &Name) {
   return isValidCPUName(Name);
 }
 
+void AArch64TargetInfo::fillValidCPUList(
+    SmallVectorImpl<StringRef> &Values) const {
+  llvm::AArch64::fillValidCPUArchList(Values);
+}
+
 void AArch64TargetInfo::getTargetDefinesARMV81A(const LangOptions &Opts,
                                                 MacroBuilder &Builder) const {
   Builder.defineMacro("__ARM_FEATURE_QRDMX", "1");

clang/lib/Basic/Targets/AArch64.h

@@ -46,6 +46,7 @@ public:
   bool setABI(const std::string &Name) override;
 
   bool isValidCPUName(StringRef Name) const override;
+  void fillValidCPUList(SmallVectorImpl<StringRef> &Values) const override;
   bool setCPU(const std::string &Name) override;
 
   bool useFP16ConversionIntrinsics() const override {

clang/lib/Basic/Targets/ARM.cpp

@@ -478,6 +478,10 @@ bool ARMTargetInfo::isValidCPUName(StringRef Name) const {
          llvm::ARM::parseCPUArch(Name) != llvm::ARM::ArchKind::INVALID;
 }
 
+void ARMTargetInfo::fillValidCPUList(SmallVectorImpl<StringRef> &Values) const {
+  llvm::ARM::fillValidCPUArchList(Values);
+}
+
 bool ARMTargetInfo::setCPU(const std::string &Name) {
   if (Name != "generic")
     setArchInfo(llvm::ARM::parseCPUArch(Name));

clang/lib/Basic/Targets/ARM.h

@@ -122,6 +122,8 @@ public:
   bool hasFeature(StringRef Feature) const override;
 
   bool isValidCPUName(StringRef Name) const override;
+  void fillValidCPUList(SmallVectorImpl<StringRef> &Values) const override;
+
   bool setCPU(const std::string &Name) override;
 
   bool setFPMath(StringRef Name) override;