1. Make resource dir unique and global.

2. Use our custom CDB loader.

src/Compiler/Command.cpp

@@ -0,0 +1,69 @@
+#include "Compiler/Command.h"
+#include "llvm/Support/Program.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace clice {
+
+llvm::Error mangleCommand(llvm::StringRef command,
+                          llvm::SmallVectorImpl<const char*>& out,
+                          llvm::SmallVectorImpl<char>& buffer) {
+    llvm::SmallString<128> current;
+    llvm::SmallVector<uint32_t> indices;
+    bool inSingleQuote = false;
+    bool inDoubleQuote = false;
+
+    for(size_t i = 0; i < command.size(); ++i) {
+        char c = command[i];
+        if(c == ' ' && !inSingleQuote && !inDoubleQuote) {
+            if(!current.empty()) {
+                indices.push_back(buffer.size());
+                buffer.append(current);
+                buffer.push_back('\0');
+                current.clear();
+            }
+        } else if(c == '\'' && !inDoubleQuote) {
+            inSingleQuote = !inSingleQuote;
+        } else if(c == '"' && !inSingleQuote) {
+            inDoubleQuote = !inDoubleQuote;
+        } else {
+            current.push_back(c);
+        }
+    }
+
+    if(!current.empty()) {
+        indices.push_back(buffer.size());
+        buffer.append(current);
+        buffer.push_back('\0');
+    }
+
+    /// Add resource directory.
+    indices.push_back(buffer.size());
+    current = std::format("-resource-dir={}", fs::resource_dir);
+    buffer.append(current);
+    buffer.push_back('\0');
+
+    /// FIXME: use better way to remove args.
+    for(size_t i = 0; i < indices.size(); ++i) {
+        llvm::StringRef arg(buffer.data() + indices[i]);
+
+        /// Skip `-c` and `-o` arguments.
+        if(arg == "-c") {
+            continue;
+        }
+
+        if(arg.starts_with("-o")) {
+            if(arg == "-o") {
+                ++i;
+            }
+            continue;
+        }
+
+        /// TODO: remove PCH.
+
+        out.push_back(arg.data());
+    }
+
+    return llvm::Error::success();
+}
+
+}  // namespace clice