declare_args() {
  # The target archs LLVM should support. Defaults to the host arch.
  # Set to a list, e.g. `llvm_targets_to_build = [ "X86", "ARM" ]`,
  # or to the string "all" to get all known targets.
  llvm_targets_to_build = "host"
}

if (llvm_targets_to_build == "host") {
  if (host_cpu == "arm64") {
    llvm_targets_to_build = [ "AArch64" ]
  } else if (host_cpu == "arm") {
    llvm_targets_to_build = [ "ARM" ]
  } else if (host_cpu == "ppc" || host_cpu == "ppc64") {
    llvm_targets_to_build = [ "PowerPC" ]
  } else if (host_cpu == "x86" || host_cpu == "x64") {
    llvm_targets_to_build = [ "X86" ]
  } else {
    assert(false, "add your host_cpu above")
  }
} else if (llvm_targets_to_build == "all") {
  # FIXME: Port the remaining targets.
  llvm_targets_to_build = [
    "AArch64",
    "AMDGPU",
    "ARM",
    "BPF",
    "Hexagon",
    "Lanai",
    "Mips",
    "NVPTX",
    "PowerPC",
    "Sparc",
    "SystemZ",
    "WebAssembly",
    "X86",
  ]
}

# Validate that llvm_targets_to_build is set to a list of valid targets,
# and remember which targets are built.
llvm_build_AArch64 = false
llvm_build_ARM = false
llvm_build_BPF = false
llvm_build_PowerPC = false
llvm_build_WebAssembly = false
llvm_build_X86 = false
foreach(target, llvm_targets_to_build) {
  if (target == "AArch64") {
    llvm_build_AArch64 = true
  } else if (target == "AMDGPU") {
    # Nothing to do.
  } else if (target == "ARM") {
    llvm_build_ARM = true
  } else if (target == "BPF") {
    llvm_build_BPF = true
  } else if (target == "Hexagon") {
    # Nothing to do.
  } else if (target == "Lanai") {
    # Nothing to do.
  } else if (target == "Mips") {
    # Nothing to do.
  } else if (target == "NVPTX") {
    # Nothing to do.
  } else if (target == "PowerPC") {
    llvm_build_PowerPC = true
  } else if (target == "RISCV") {
    # Nothing to do.
  } else if (target == "Sparc") {
    # Nothing to do.
  } else if (target == "SystemZ") {
    # Nothing to do.
  } else if (target == "WebAssembly") {
    llvm_build_WebAssembly = true
  } else if (target == "X86") {
    llvm_build_X86 = true
  } else {
    # FIXME: Port the remaining targets.
    assert(false, "Unknown target '$target'.")
  }
}

# FIXME: This should be based off target_cpu once cross compiles work.
if (host_cpu == "arm64") {
  native_target = "AArch64"
} else if (host_cpu == "arm") {
  native_target = "ARM"
} else if (host_cpu == "ppc" || host_cpu == "ppc64") {
  native_target = "PowerPC"
} else if (host_cpu == "x86" || host_cpu == "x64") {
  native_target = "X86"
} else {
  assert(false, "Unsuppored host_cpu '$host_cpu'.")
}