[ifs] Print an error when llvm-ifs is supplied with an unknown arch

[haowei]

Summary

This patch makes llvm-ifs print an error when the arch string from

'--arch' flag or the IFS file 'Arch' field is unknown.

[jhenderson]

llvm/lib/InterfaceStub/IFSHandler.cpp

199–201

I know this is following existing practice a few lines up, but 1) could this use createStringError and 2) don't end error messages in a full stop (see the coding standards).

llvm/tools/llvm-ifs/llvm-ifs.cpp

339

Similar to above: no leading capital error or trailing punctuation at the end of an error message (see the coding standards).

[haowei]

Thanks for pointing them out.

[mcgrathr]

lgtm

llvm/lib/InterfaceStub/IFSHandler.cpp

if (std::error_code Err = YamlIn.error()) {
     return createStringError(Err, "YAML failed reading as IFS");
   }
 
   if (Stub->IfsVersion > IFSVersionCurrent)
     return make_error<StringError>(
         "IFS version " + Stub->IfsVersion.getAsString() + " is unsupported.",
         std::make_error_code(std::errc::invalid_argument));
   if (Stub->Target.ArchString) {
-    Stub->Target.Arch =
+    uint16_t eMachine =
         ELF::convertArchNameToEMachine(*Stub->Target.ArchString);
+    if (eMachine == ELF::EM_NONE)
+      return createStringError(
+          std::make_error_code(std::errc::invalid_argument),
+          "IFS arch '" + *Stub->Target.ArchString + "' is unsupported");
+    Stub->Target.Arch = eMachine;
   }
   return std::move(Stub);
 }
 
 Error ifs::writeIFSToOutputStream(raw_ostream &OS, const IFSStub &Stub) {
   yaml::Output YamlOut(OS, nullptr, /*WrapColumn =*/0);
   std::unique_ptr<IFSStubTriple> CopyStub(new IFSStubTriple(Stub));
   if (Stub.Target.Arch) {

llvm/test/tools/llvm-ifs/ifs-read-invalid-arch.test

+# RUN: not llvm-ifs --output-ifs=- %s 2>&1 | FileCheck %s
+
+--- !ifs-v1
+SoName: somelib.so
+IfsVersion: 3.0
+Target: { ObjectFormat: ELF, Arch: RiscV64, Endianness: little, BitWidth: 64 }
+Symbols:
+  - { Name: foo, Type: Func }
+  - { Name: bar, Type: Object, Size: 42 }
+  - { Name: baz, Type: Object, Size: 8 }
+  - { Name: not, Type: Object, Size: 128, Undefined: true }
+  - { Name: nor, Type: Func, Undefined: true }
+...
+
+# CHECK: error: IFS arch 'RiscV64' is unsupported

llvm/test/tools/llvm-ifs/write-stub.test

 
 # RUN: llvm-ifs --output-ifs=%t.ifs --output-elf=%t.elf --target=x86_64-linux-gnu %s
 # RUN: llvm-ifs --output-elf=%t.elf2 --target=x86_64-linux-gnu %t.ifs
 # RUN: llvm-readobj -h -S --string-dump .dynstr --string-dump .shstrtab --dyn-symbols --dynamic-table %t.elf | FileCheck %s -DCLASS="64-bit (0x2)" -DDE="LittleEndian (0x1)" -DHS=64 -DPHES=56 -DSHES=64 -DDYNSYMAL=8 -DDYNSYMES=24 -DDYNAMICAL=8 -DDYNAMICES=16 -DDYNTABZ=000000000
 # RUN: llvm-readobj -h -S --string-dump .dynstr --string-dump .shstrtab --dyn-symbols --dynamic-table %t.elf2 | FileCheck %s -DCLASS="64-bit (0x2)" -DDE="LittleEndian (0x1)" -DHS=64 -DPHES=56 -DSHES=64 -DDYNSYMAL=8 -DDYNSYMES=24 -DDYNAMICAL=8 -DDYNAMICES=16 -DDYNTABZ=000000000
 
 # RUN: llvm-ifs --output-elf=- --target=riscv64-linux-gnu %s | llvm-readelf -h - | FileCheck %s --check-prefix=MACHINE
 
+# RUN: not llvm-ifs --output-elf=- --arch=riscv64 --endianness=little --bitwidth=64 %s 2>&1 | FileCheck %s -DMSG=riscv64 --check-prefix=ARCHERR
+
 --- !ifs-v1
 IfsVersion: 3.0
 NeededLibs:
   - libc.so.6
 Symbols:
   - { Name: bar, Type: Object, Size: 42 }
   - { Name: baz, Type: TLS, Size: 3 }
   - { Name: plus, Type: Func }

 # CHECK-NEXT: [    11] .dynamic
 # CHECK-NEXT: [    1a] .shstrtab
 
 # TRIPLEERR: error: Target triple cannot be used simultaneously with ELF target format
 # TARGETERR: error: [[MSG]] is not defined in the text stub
 # CONFLICTERR: error: Supplied [[MSG]] conflicts with the text stub
 
 # MACHINE: Machine: RISC-V
+
+# ARCHERR: error: unknown arch '[[MSG]]'

llvm/tools/llvm-ifs/llvm-ifs.cpp

if (const opt::Arg *A = Args.getLastArg(OPT_output_format_EQ)) {
     Config.OutputFormat = StringSwitch<std::optional<FileFormat>>(A->getValue())
                               .Case("IFS", FileFormat::IFS)
                               .Case("ELF", FileFormat::ELF)
                               .Case("TBD", FileFormat::TBD)
                               .Default(std::nullopt);
     if (!Config.OutputFormat)
       OptionNotFound("--output-format", A->getValue());
   }
-  if (const opt::Arg *A = Args.getLastArg(OPT_arch_EQ))
-    Config.OverrideArch = ELF::convertArchNameToEMachine(A->getValue());
-
+  if (const opt::Arg *A = Args.getLastArg(OPT_arch_EQ)) {
+    uint16_t eMachine = ELF::convertArchNameToEMachine(A->getValue());
+    if (eMachine == ELF::EM_NONE) {
+      fatalError(Twine("unknown arch '") + A->getValue() + "'");
+    }
+    Config.OverrideArch = eMachine;
+  }
   if (const opt::Arg *A = Args.getLastArg(OPT_bitwidth_EQ)) {
     size_t Width;
     llvm::StringRef S(A->getValue());
     if (!S.getAsInteger<size_t>(10, Width) || Width == 64 || Width == 32)
       Config.OverrideBitWidth =
           Width == 64 ? IFSBitWidthType::IFS64 : IFSBitWidthType::IFS32;
     else
       OptionNotFound("--bitwidth", A->getValue());