fix: Add LLVM detection debugging and fallback paths

- Add debugging step to verify LLVM_DIR before configuration
- Add Windows-specific fallback search paths for LLVMConfig.cmake
- Improve LLVM_DIR variable handling in CMake invocation
- Search common LLVM installation paths on Windows

This should help diagnose and fix the LLVM package detection issue.

Author: ProgrammerKR

.github/workflows/build.yml

@@ -81,6 +81,21 @@ jobs:
         if: matrix.os == 'windows-latest'
         run: choco install ninja -y
 
+      - name: Debug LLVM Configuration (Windows)
+        if: matrix.os == 'windows-latest'
+        shell: pwsh
+        run: |
+          Write-Host "LLVM_DIR: $env:LLVM_DIR"
+          Write-Host "LLVM_ROOT: $env:LLVM_ROOT"
+          Write-Host "Checking if LLVMConfig.cmake exists..."
+          if (Test-Path "$env:LLVM_DIR/LLVMConfig.cmake") {
+            Write-Host "✓ Found LLVMConfig.cmake at $env:LLVM_DIR/LLVMConfig.cmake"
+          } else {
+            Write-Host "✗ LLVMConfig.cmake not found at $env:LLVM_DIR"
+            Write-Host "Searching for LLVMConfig.cmake..."
+            Get-ChildItem -Path "$env:LLVM_ROOT" -Filter "LLVMConfig.cmake" -Recurse -ErrorAction SilentlyContinue | Select-Object -First 5 | ForEach-Object { Write-Host $_.FullName }
+          }
+
       - name: Configure (Unix)
         if: matrix.os != 'windows-latest'
         shell: bash
@@ -94,14 +109,17 @@ jobs:
         if: matrix.os == 'windows-latest'
         shell: pwsh
         run: |
+          $llvmDir = $env:LLVM_DIR
+          Write-Host "Using LLVM_DIR: $llvmDir"
+          
           cmake -S . -B build `
              -G "Ninja" `
              -DCMAKE_BUILD_TYPE=${{ env.BUILD_TYPE }} `
              -DBUILD_TESTS=OFF `
              -DBUILD_BENCH=OFF `
              -DCMAKE_C_COMPILER="$env:LLVM_ROOT/bin/clang.exe" `
              -DCMAKE_CXX_COMPILER="$env:LLVM_ROOT/bin/clang++.exe" `
-             -DLLVM_DIR="$env:LLVM_DIR" `
+             -DLLVM_DIR="$llvmDir" `
              -DCMAKE_PREFIX_PATH="$env:LLVM_ROOT"
 
       - name: Build

CMakeLists.txt

@@ -17,6 +17,26 @@ endif()
 # --- LLVM Configuration ---
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/modules")
 
+# Add explicit hints for LLVM on Windows
+if(WIN32 AND NOT LLVM_DIR)
+    message(STATUS "Searching for LLVM on Windows...")
+    # Common LLVM installation paths on Windows
+    set(LLVM_SEARCH_PATHS
+        "C:/Program Files/LLVM/lib/cmake/llvm"
+        "C:/Program Files/LLVM/share/llvm/cmake"
+        "C:/Program Files (x86)/LLVM/lib/cmake/llvm"
+        "C:/Program Files (x86)/LLVM/share/llvm/cmake"
+    )
+    
+    foreach(search_path ${LLVM_SEARCH_PATHS})
+        if(EXISTS "${search_path}/LLVMConfig.cmake")
+            set(LLVM_DIR "${search_path}" CACHE PATH "LLVM CMake directory")
+            message(STATUS "Found LLVM CMake files at: ${search_path}")
+            break()
+        endif()
+    endforeach()
+endif()
+
 # --- LLVM Configuration ---
 find_package(LLVM CONFIG REQUIRED)