[clang] [Driver] Teach Barmetal toolchain about GCC installation (PR #121829)

[Garvit Gupta via cfe-commits]

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@@ -110,20 +110,76 @@ static std::string computeBaseSysRoot(const Driver &D, bool IncludeTriple) {
   return std::string(SysRootDir);
 }
 
+std::string BareMetal::computeSysRoot() const {
+  if (!SysRoot.empty())
+    return SysRoot;
+
+  std::string SysRoot = getDriver().SysRoot;
+  if (!SysRoot.empty())
+    return SysRoot;
+
+  // Verify the GCC installation from -gcc-install-dir, --gcc-toolchain, or
+  // alongside clang. If valid, form the sysroot. Otherwise, check
+  // lib/clang-runtimes above the driver.
+  SmallString<128> SysRootDir;
+  if (GCCInstallation.isValid()) {
+    StringRef LibDir = GCCInstallation.getParentLibPath();
+    StringRef TripleStr = GCCInstallation.getTriple().str();
+    llvm::sys::path::append(SysRootDir, LibDir, "..", TripleStr);
+  } else {
+    // Use the triple as provided to the driver. Unlike the parsed triple
+    // this has not been normalized to always contain every field.
+    llvm::sys::path::append(SysRootDir, getDriver().Dir, "..",
+                            getDriver().getTargetTriple());
+  }
+
+  if (llvm::sys::fs::exists(SysRootDir))
+    return std::string(SysRootDir);
+  SysRoot = computeBaseSysRoot(getDriver(), /*IncludeTriple*/ true);
+
+  return SysRoot;
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quic-garvgupt wrote:

Thanks for pointing this out!. I have fixed it in the next patchset

https://github.com/llvm/llvm-project/pull/121829