[clang] [RISCV] Merging RISCVToolChain and BareMetal toolchains (PR #118809)

[Petr Hosek via cfe-commits]

================
@@ -291,6 +365,36 @@ BareMetal::OrderedMultilibs BareMetal::getOrderedMultilibs() const {
   return llvm::reverse(Default);
 }
 
+ToolChain::CXXStdlibType BareMetal::GetDefaultCXXStdlibType() const {
+  if (getTriple().isRISCV()) {
+    return GCCInstallation.isValid() ? ToolChain::CST_Libstdcxx
+                                     : ToolChain::CST_Libcxx;
+  }
+  return ToolChain::CST_Libcxx;
+}
+
+ToolChain::RuntimeLibType BareMetal::GetDefaultRuntimeLibType() const {
+  if (getTriple().isRISCV()) {
+    return GCCInstallation.isValid() ? ToolChain::RLT_Libgcc
+                                     : ToolChain::RLT_CompilerRT;
+  }
+  return ToolChain::RLT_CompilerRT;
----------------
petrhosek wrote:

```suggestion
if (getTriple().isRISCV() && GCCInstallation.isValid())
  return ToolChain::RLT_Libgcc;
return ToolChain::RLT_CompilerRT;
```

https://github.com/llvm/llvm-project/pull/118809