Port most of `LLVMRustPrintTargetCPUs` to Rust

1 files changed, 7 insertions, 39 deletions

diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
index 245edde2768..e571e1900ca 100644
--- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -317,49 +317,17 @@ template <typename KV> static size_t getLongestEntryLength(ArrayRef<KV> Table) {
   return MaxLen;
 }
 
-using PrintBackendInfo = void(void *, const char *Data, size_t Len);
-
 extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef TM,
-                                        const char *TargetCPU,
-                                        PrintBackendInfo Print, void *Out) {
-  const TargetMachine *Target = unwrap(TM);
-  const Triple::ArchType HostArch =
-      Triple(sys::getDefaultTargetTriple()).getArch();
-  const Triple::ArchType TargetArch = Target->getTargetTriple().getArch();
+                                        RustStringRef OutStr) {
+  ArrayRef<SubtargetSubTypeKV> CPUTable =
+      unwrap(TM)->getMCSubtargetInfo()->getAllProcessorDescriptions();
+  auto OS = RawRustStringOstream(OutStr);
 
-  std::ostringstream Buf;
-
-  const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo();
-  const ArrayRef<SubtargetSubTypeKV> CPUTable =
-      MCInfo->getAllProcessorDescriptions();
-  unsigned MaxCPULen = getLongestEntryLength(CPUTable);
-
-  Buf << "Available CPUs for this target:\n";
-  // Don't print the "native" entry when the user specifies --target with a
-  // different arch since that could be wrong or misleading.
-  if (HostArch == TargetArch) {
-    MaxCPULen = std::max(MaxCPULen, (unsigned)std::strlen("native"));
-    const StringRef HostCPU = sys::getHostCPUName();
-    Buf << "    " << std::left << std::setw(MaxCPULen) << "native"
-        << " - Select the CPU of the current host "
-           "(currently "
-        << HostCPU.str() << ").\n";
-  }
+  // Just print a bare list of target CPU names, and let Rust-side code handle
+  // the full formatting of `--print=target-cpus`.
   for (auto &CPU : CPUTable) {
-    // Compare cpu against current target to label the default
-    if (strcmp(CPU.Key, TargetCPU) == 0) {
-      Buf << "    " << std::left << std::setw(MaxCPULen) << CPU.Key
-          << " - This is the default target CPU for the current build target "
-             "(currently "
-          << Target->getTargetTriple().str() << ").";
-    } else {
-      Buf << "    " << CPU.Key;
-    }
-    Buf << "\n";
+    OS << CPU.Key << "\n";
   }
-
-  const auto &BufString = Buf.str();
-  Print(Out, BufString.data(), BufString.size());
 }
 
 extern "C" size_t LLVMRustGetTargetFeaturesCount(LLVMTargetMachineRef TM) {