Revert "[lldb][NFC] remove the ResolveSDKPathFromDebugInfo method (llvm#145744)"

This reverts commit 7381d81.

Author: charles-zablit

lldb/include/lldb/Target/Platform.h

@@ -458,6 +458,22 @@ class Platform : public PluginInterface {
                       LLVM_PRETTY_FUNCTION, GetName()));
   }
 
+  /// Returns the full path of the most appropriate SDK for the
+  /// specified 'module'. This function gets this path by parsing
+  /// debug-info (see \ref `GetSDKPathFromDebugInfo`).
+  ///
+  /// \param[in] module Module whose debug-info to parse for
+  ///                   which SDK it was compiled against.
+  ///
+  /// \returns If successful, returns the full path to an
+  ///          Xcode SDK.
+  virtual llvm::Expected<std::string>
+  ResolveSDKPathFromDebugInfo(Module &module) {
+    return llvm::createStringError(
+        llvm::formatv("{0} not implemented for '{1}' platform.",
+                      LLVM_PRETTY_FUNCTION, GetName()));
+  }
+
   /// Search CU for the SDK path the CUs was compiled against.
   ///
   /// \param[in] unit The CU

lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp

@@ -1130,33 +1130,13 @@ void PlatformDarwin::AddClangModuleCompilationOptionsForSDKType(
 
   if (target) {
     if (ModuleSP exe_module_sp = target->GetExecutableModule()) {
-      SymbolFile *sym_file = exe_module_sp->GetSymbolFile();
-      if (!sym_file)
-        return;
-
-      XcodeSDK merged_sdk;
-      for (unsigned i = 0; i < sym_file->GetNumCompileUnits(); ++i) {
-        if (auto cu_sp = sym_file->GetCompileUnitAtIndex(i)) {
-          auto cu_sdk = sym_file->ParseXcodeSDK(*cu_sp);
-          merged_sdk.Merge(cu_sdk);
-        }
-      }
-
-      // TODO: The result of this loop is almost equivalent to deriving the SDK
-      // from the target triple, which would be a lot cheaper.
-
-      if (FileSystem::Instance().Exists(merged_sdk.GetSysroot())) {
-        sysroot_spec = merged_sdk.GetSysroot();
+      auto path_or_err = ResolveSDKPathFromDebugInfo(*exe_module_sp);
+      if (path_or_err) {
+        sysroot_spec = FileSpec(*path_or_err);
       } else {
-        auto path_or_err =
-            HostInfo::GetSDKRoot(HostInfo::SDKOptions{merged_sdk});
-        if (path_or_err) {
-          sysroot_spec = FileSpec(*path_or_err);
-        } else {
-          LLDB_LOG_ERROR(GetLog(LLDBLog::Types | LLDBLog::Host),
-                         path_or_err.takeError(),
-                         "Failed to resolve SDK path: {0}");
-        }
+        LLDB_LOG_ERROR(GetLog(LLDBLog::Types | LLDBLog::Host),
+                       path_or_err.takeError(),
+                       "Failed to resolve SDK path: {0}");
       }
     }
   }
@@ -1404,6 +1384,31 @@ PlatformDarwin::GetSDKPathFromDebugInfo(Module &module) {
   return std::pair{std::move(merged_sdk), found_mismatch};
 }
 
+llvm::Expected<std::string>
+PlatformDarwin::ResolveSDKPathFromDebugInfo(Module &module) {
+  auto sdk_or_err = GetSDKPathFromDebugInfo(module);
+  if (!sdk_or_err)
+    return llvm::createStringError(
+        llvm::inconvertibleErrorCode(),
+        llvm::formatv("Failed to parse SDK path from debug-info: {0}",
+                      llvm::toString(sdk_or_err.takeError())));
+
+  auto [sdk, _] = std::move(*sdk_or_err);
+
+  if (FileSystem::Instance().Exists(sdk.GetSysroot()))
+    return sdk.GetSysroot().GetPath();
+
+  auto path_or_err = HostInfo::GetSDKRoot(HostInfo::SDKOptions{sdk});
+  if (!path_or_err)
+    return llvm::createStringError(
+        llvm::inconvertibleErrorCode(),
+        llvm::formatv("Error while searching for SDK (XcodeSDK '{0}'): {1}",
+                      sdk.GetString(),
+                      llvm::toString(path_or_err.takeError())));
+
+  return path_or_err->str();
+}
+
 llvm::Expected<XcodeSDK>
 PlatformDarwin::GetSDKPathFromDebugInfo(CompileUnit &unit) {
   ModuleSP module_sp = unit.CalculateSymbolContextModule();

lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.h

@@ -120,6 +120,9 @@ class PlatformDarwin : public PlatformPOSIX {
   llvm::Expected<std::pair<XcodeSDK, bool>>
   GetSDKPathFromDebugInfo(Module &module) override;
 
+  llvm::Expected<std::string>
+  ResolveSDKPathFromDebugInfo(Module &module) override;
+
   llvm::Expected<XcodeSDK> GetSDKPathFromDebugInfo(CompileUnit &unit) override;
 
   llvm::Expected<std::string>

lldb/unittests/SymbolFile/DWARF/XcodeSDKModuleTests.cpp

@@ -161,6 +161,9 @@ TEST_F(XcodeSDKModuleTests, TestSDKPathFromDebugInfo_InvalidSDKPath) {
 
   auto platform_sp = Platform::GetHostPlatform();
   ASSERT_TRUE(platform_sp);
+  auto path_or_err = platform_sp->ResolveSDKPathFromDebugInfo(*module);
+  EXPECT_FALSE(static_cast<bool>(path_or_err));
+  llvm::consumeError(path_or_err.takeError());
 }
 
 TEST_F(XcodeSDKModuleTests, TestSDKPathFromDebugInfo_No_DW_AT_APPLE_sdk) {
@@ -204,6 +207,9 @@ TEST_F(XcodeSDKModuleTests, TestSDKPathFromDebugInfo_No_DW_AT_APPLE_sdk) {
 
   auto platform_sp = Platform::GetHostPlatform();
   ASSERT_TRUE(platform_sp);
+  auto path_or_err = platform_sp->ResolveSDKPathFromDebugInfo(*module);
+  EXPECT_FALSE(static_cast<bool>(path_or_err));
+  llvm::consumeError(path_or_err.takeError());
 }
 
 TEST_P(SDKPathParsingMultiparamTests, TestSDKPathFromDebugInfo) {