[Driver] Warn about -mios-version-min instead of erroring out when targeting MachO embedded architectures

[ahatanak]

Summary

Sometimes users pass this option when targeting embedded architectures like armv7m on non-darwin platforms.

Emit a warning instead of erroring out, which restores the behavior prior to 34d7acd444b88342fc93fca202608c1e16fa5946.

[MaskRay]

LGTM.

clang/test/Driver/macho-embedded.c

9

-target is deprecated since Clang 3.4 (274b6f0c87a6a1798de0a68135afc7f95def6277). Use --target= for new tests?

-fdriver-only may be slightly better than -### as -fdriver-only causes clang to return with non-zero upon an error, while -### doesn't.

[MaskRay]

clang/test/Driver/macho-embedded.c

16

Without the change, this may fail for some vendors and this is the reason that some tests have -no-canonical-prefixes (I have cleaned up a lot). For errors and warnings, we usually don't test the string before error/warning anyway.

[ahatanak]

Thank you for the review. 509d051606e837d1b8291743cd1683cf8c582afc

clang/lib/Driver/Driver.cpp

static llvm::Triple computeTargetTriple(const Driver &D,
   // being the Hurd OS.
   if (TargetTriple.contains("-unknown-gnu") || TargetTriple.contains("-pc-gnu"))
     Target.setOSName("hurd");
 
   // Handle Apple-specific options available here.
   if (Target.isOSBinFormatMachO()) {
     // If an explicit Darwin arch name is given, that trumps all.
     if (!DarwinArchName.empty()) {
-      tools::darwin::setTripleTypeForMachOArchName(Target, DarwinArchName);
+      tools::darwin::setTripleTypeForMachOArchName(Target, DarwinArchName,
+                                                   Args);
       return Target;
     }
 
     // Handle the Darwin '-arch' flag.
     if (Arg *A = Args.getLastArg(options::OPT_arch)) {
       StringRef ArchName = A->getValue();
-      tools::darwin::setTripleTypeForMachOArchName(Target, ArchName);
+      tools::darwin::setTripleTypeForMachOArchName(Target, ArchName, Args);
     }
   }
 
   // Handle pseudo-target flags '-mlittle-endian'/'-EL' and
   // '-mbig-endian'/'-EB'.
   if (Arg *A = Args.getLastArgNoClaim(options::OPT_mlittle_endian,
                                       options::OPT_mbig_endian)) {
     llvm::Triple T = A->getOption().matches(options::OPT_mlittle_endian)

clang/lib/Driver/ToolChains/Darwin.h

 namespace toolchains {
 class MachO;
 } // end namespace toolchains
 
 namespace tools {
 
 namespace darwin {
 llvm::Triple::ArchType getArchTypeForMachOArchName(StringRef Str);
-void setTripleTypeForMachOArchName(llvm::Triple &T, StringRef Str);
+void setTripleTypeForMachOArchName(llvm::Triple &T, StringRef Str,
+                                   const llvm::opt::ArgList &Args);
 
 class LLVM_LIBRARY_VISIBILITY MachOTool : public Tool {
   virtual void anchor();
 
 protected:
   void AddMachOArch(const llvm::opt::ArgList &Args,
                     llvm::opt::ArgStringList &CmdArgs) const;
 

clang/lib/Driver/ToolChains/Darwin.cpp

return llvm::StringSwitch<llvm::Triple::ArchType>(Str)
       .Case("amdgcn", llvm::Triple::amdgcn)
       .Case("nvptx", llvm::Triple::nvptx)
       .Case("nvptx64", llvm::Triple::nvptx64)
       .Case("amdil", llvm::Triple::amdil)
       .Case("spir", llvm::Triple::spir)
       .Default(llvm::Triple::UnknownArch);
 }
 
-void darwin::setTripleTypeForMachOArchName(llvm::Triple &T, StringRef Str) {
+void darwin::setTripleTypeForMachOArchName(llvm::Triple &T, StringRef Str,
+                                           const ArgList &Args) {
   const llvm::Triple::ArchType Arch = getArchTypeForMachOArchName(Str);
   llvm::ARM::ArchKind ArchKind = llvm::ARM::parseArch(Str);
   T.setArch(Arch);
   if (Arch != llvm::Triple::UnknownArch)
     T.setArchName(Str);
 
   if (ArchKind == llvm::ARM::ArchKind::ARMV6M ||
       ArchKind == llvm::ARM::ArchKind::ARMV7M ||
       ArchKind == llvm::ARM::ArchKind::ARMV7EM) {
+    // Don't reject -mios-version-min= if we have an iOS triple.
+    if (T.isiOS())
+      if (Arg *A = Args.getLastArgNoClaim(options::OPT_mios_version_min_EQ))
+        A->ignoreTargetSpecific();
+
     T.setOS(llvm::Triple::UnknownOS);
     T.setObjectFormat(llvm::Triple::MachO);
   }
 }
 
 void darwin::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
                                      const InputInfo &Output,
                                      const InputInfoList &Inputs,

clang/test/Driver/macho-embedded.c

 // RUN: %clang -arch armv7 -target thumbv7-apple-darwin-eabi -### -c %s 2>&1 | FileCheck %s --check-prefix=CHECK-AAPCS
 // RUN: %clang -target x86_64-apple-macosx10.9 -arch armv7m -### -c %s 2>&1 | FileCheck %s --check-prefix=CHECK-AAPCS
 // RUN: %clang -arch armv7s -target thumbv7-apple-ios -### -c %s 2>&1 | FileCheck %s --check-prefix=CHECK-APCS
 // RUN: %clang -arch armv7s -target thumbv7-apple-darwin -### -c %s 2>&1 | FileCheck %s --check-prefix=CHECK-APCS
 // RUN: %clang -arch armv6m -target thumbv7-apple-darwin -### -c %s 2>&1 | FileCheck %s --check-prefix=CHECK-MACHO-EMBEDDED
 // RUN: %clang -arch armv7m -target thumbv7-apple-darwin -### -c %s 2>&1 | FileCheck %s --check-prefix=CHECK-MACHO-EMBEDDED
 // RUN: %clang -arch armv7em -target thumbv7-apple-darwin -### -c %s 2>&1 | FileCheck %s --check-prefix=CHECK-MACHO-EMBEDDED
 
+// RUN: %clang -arch armv7m -target thumbv7-apple-ios -mios-version-min=5 -### -c %s 2>&1 | FileCheck %s --check-prefix=CHECK-MACHO-EMBEDDED-DIAG --check-prefix=CHECK-MACHO-EMBEDDED
+
 // CHECK-IOS: "-triple" "thumbv7" "thumbv7-apple-ios
 
 // CHECK-AAPCS: "-target-abi" "aapcs"
 // CHECK-APCS: "-target-abi" "apcs-gnu"
 
+// CHECK-MACHO-EMBEDDED-DIAG: clang: warning: argument unused during compilation: '-mios-version-min=5'
 // CHECK-MACHO-EMBEDDED: "-triple" "{{thumbv[67]e?m}}-apple-unknown-macho"
 // CHECK-MACHO-EMBEDDED: "-mrelocation-model" "pic"