fix: Verify and correct LLVM_DIR path dynamically

- Enhance debug step to verify LLVMConfig.cmake exists at LLVM_DIR
- Automatically search for and update LLVM_DIR if file not found
- Add LLVM_DIR validation in CMakeLists.txt before find_package
- Unset invalid LLVM_DIR to trigger fallback search
- Add C:/Program Files/LLVM/cmake to search paths

This fixes the issue where LLVM_DIR was set but pointed to a location
without LLVMConfig.cmake.

Author: ProgrammerKR

.github/workflows/build.yml

@@ -85,15 +85,30 @@ jobs:
         if: matrix.os == 'windows-latest'
         shell: pwsh
         run: |
-          Write-Host "LLVM_DIR: $env:LLVM_DIR"
+          Write-Host "Initial 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") {
+          
+          # Check if LLVMConfig.cmake exists at the set LLVM_DIR
+          if ($env:LLVM_DIR -and (Test-Path "$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 }
+            
+            # Search for LLVMConfig.cmake in LLVM installation
+            $found = Get-ChildItem -Path "$env:LLVM_ROOT" -Filter "LLVMConfig.cmake" -Recurse -ErrorAction SilentlyContinue | Select-Object -First 1
+            
+            if ($found) {
+              $correctLLVMDir = Split-Path -Parent $found.FullName
+              $correctLLVMDir = $correctLLVMDir -replace "\\\\", "/"
+              Write-Host "✓ Found LLVMConfig.cmake at: $($found.FullName)"
+              Write-Host "Updating LLVM_DIR to: $correctLLVMDir"
+              Add-Content $env:GITHUB_ENV "LLVM_DIR=$correctLLVMDir"
+              $env:LLVM_DIR = $correctLLVMDir
+            } else {
+              Write-Host "✗ Could not find LLVMConfig.cmake in $env:LLVM_ROOT"
+              exit 1
+            }
           }
 
       - name: Configure (Unix)

CMakeLists.txt

@@ -18,23 +18,32 @@ endif()
 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"
-    )
+if(WIN32)
+    # First, verify if LLVM_DIR is set and valid
+    if(LLVM_DIR AND NOT EXISTS "${LLVM_DIR}/LLVMConfig.cmake")
+        message(WARNING "LLVM_DIR is set to '${LLVM_DIR}' but LLVMConfig.cmake not found there. Searching for LLVM...")
+        unset(LLVM_DIR CACHE)
+    endif()
 
-    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()
+    # If LLVM_DIR is not set or invalid, search common paths
+    if(NOT LLVM_DIR)
+        message(STATUS "Searching for LLVM on Windows...")
+        set(LLVM_SEARCH_PATHS
+            "C:/Program Files/LLVM/lib/cmake/llvm"
+            "C:/Program Files/LLVM/share/llvm/cmake"
+            "C:/Program Files/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()
 endif()
 
 # --- LLVM Configuration ---