fix: exhaustive LLVM detection failure on Windows

Author: ProgrammerKR

.github/workflows/build.yml

@@ -54,16 +54,43 @@ jobs:
         shell: pwsh
         run: |
           function Find-LLVM {
-            $searchPaths = @("C:\Program Files\LLVM", "C:\Program Files (x86)\LLVM", "C:\ProgramData\chocolatey", "C:\tools\llvm")
+            $possiblePaths = @(
+              "C:\Program Files\LLVM",
+              "C:\Program Files (x86)\LLVM",
+              "C:\ProgramData\chocolatey\lib\llvm\tools\llvm",
+              "C:\tools\llvm",
+              "$env:ProgramFiles\LLVM",
+              "$env:ProgramFiles(x86)\LLVM"
+            )
+            
+            Write-Host "Searching for LLVM in standard locations..."
             
             # 1. Try to find llvm-config.exe
             $config = Get-Command llvm-config -ErrorAction SilentlyContinue | Select-Object -ExpandProperty Source
             if (-not $config) {
-              $config = Get-ChildItem -Path $searchPaths -Filter "llvm-config.exe" -Recurse -Depth 4 -ErrorAction SilentlyContinue | Select-Object -First 1 -ExpandProperty FullName
+              foreach ($path in $possiblePaths) {
+                if (Test-Path "$path\bin\llvm-config.exe") {
+                  $config = "$path\bin\llvm-config.exe"
+                  break
+                }
+                # Fallback recursive search if not in bin
+                $found = Get-ChildItem -Path $path -Filter "llvm-config.exe" -Recurse -Depth 4 -ErrorAction SilentlyContinue | Select-Object -First 1
+                if ($found) {
+                  $config = $found.FullName
+                  break
+                }
+              }
             }
             
             # 2. Try to find LLVMConfig.cmake
-            $cmake = Get-ChildItem -Path $searchPaths -Filter "LLVMConfig.cmake" -Recurse -Depth 6 -ErrorAction SilentlyContinue | Select-Object -First 1 -ExpandProperty FullName
+            $cmake = $null
+            foreach ($path in $possiblePaths) {
+              $found = Get-ChildItem -Path $path -Filter "LLVMConfig.cmake" -Recurse -Depth 6 -ErrorAction SilentlyContinue | Select-Object -First 1
+              if ($found) {
+                $cmake = $found.FullName
+                break
+              }
+            }
             
             return @{ Config = $config; CMake = $cmake }
           }
@@ -72,6 +99,10 @@ jobs:
           if (-not $res.Config -and -not $res.CMake) {
             Write-Host "LLVM not found. Attempting to install LLVM 17.0.6 via Chocolatey..."
             choco install llvm -y --version 17.0.6 --allow-downgrade --limit-output
+            
+            # Refresh environment to pick up PATH changes
+            $env:PATH = [System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path","User")
+            
             $res = Find-LLVM
           }
 
@@ -80,23 +111,47 @@ jobs:
               Write-Host "Found llvm-config at: $($res.Config)"
               $llvmBin = Split-Path -Parent $res.Config
               $llvmRoot = Split-Path -Parent $llvmBin
-              $cmakeDir = & $res.Config --cmakedir
+              
+              # Try to get cmake dir from llvm-config
+              try {
+                $cmakeDir = & $res.Config --cmakedir
+                Write-Host "Detected LLVM_DIR from llvm-config: $cmakeDir"
+              } catch {
+                # Fallback if --cmakedir fails
+                $cmakeDir = Join-Path $llvmRoot "lib\cmake\llvm"
+              }
+              
+              if (-not (Test-Path $cmakeDir)) {
+                  # Second fallback
+                  $foundCmake = Get-ChildItem -Path $llvmRoot -Filter "LLVMConfig.cmake" -Recurse -Depth 5 -ErrorAction SilentlyContinue | Select-Object -First 1
+                  if ($foundCmake) { $cmakeDir = $foundCmake.DirectoryName }
+              }
+
               echo "LLVM_DIR=$cmakeDir" >> $env:GITHUB_ENV
               echo "CMAKE_PREFIX_PATH=$llvmRoot" >> $env:GITHUB_ENV
               echo "$llvmBin" >> $env:GITHUB_PATH
             } elseif ($res.CMake) {
               Write-Host "Found LLVMConfig.cmake at: $($res.CMake)"
               $cmakeDir = Split-Path -Parent $res.CMake
-              $llvmRoot = Split-Path -Parent (Split-Path -Parent (Split-Path -Parent $cmakeDir))
+              # Heuristic to find root from cmake dir (typically lib/cmake/llvm)
+              $llvmRoot = $cmakeDir
+              for ($i=0; $i -lt 3; $i++) { $llvmRoot = Split-Path -Parent $llvmRoot }
+              
               echo "LLVM_DIR=$cmakeDir" >> $env:GITHUB_ENV
               echo "CMAKE_PREFIX_PATH=$llvmRoot" >> $env:GITHUB_ENV
+              
+              $binDir = Join-Path $llvmRoot "bin"
+              if (Test-Path $binDir) {
+                echo "$binDir" >> $env:GITHUB_PATH
+              }
             }
           } else {
-            Write-Error "Exhaustive LLVM detection failed!"
+            Write-Error "Exhaustive LLVM detection failed after installation!"
             exit 1
           }
 
 
+
       - name: Configure (Unix)
         if: matrix.os != 'windows-latest'
         shell: bash