Fix Windows LLVM CI linking

Author: ciaranra

.github/workflows/rust-test.yml

@@ -294,4 +294,26 @@ jobs:
 
       - name: Run tests (Windows)
         if: runner.os == 'Windows'
-        run: cargo run --locked -p pecos-cli --release -- rust test
+        shell: bash
+        run: |
+          set -euo pipefail
+          # Windows CI uses the official LLVM development archive, which is
+          # static-only for MSVC. Keep this lane targeted so it still exercises
+          # LLVM without fanning out many static HUGR linker jobs at once.
+          cargo test --locked --workspace --release \
+            --exclude pecos-rslib \
+            --exclude pecos-rslib-cuda \
+            --exclude pecos-julia-ffi \
+            --exclude pecos-go-ffi \
+            --exclude pecos-rslib-exp \
+            --exclude pecos-rslib-llvm \
+            --exclude pecos-cuquantum \
+            --exclude pecos-cli \
+            --exclude pecos-decoders \
+            --exclude pecos-gpu-sims \
+            --exclude pecos-hugr-qis \
+            --exclude pecos-llvm
+          cargo test --locked -p pecos-cli --features=runtime --release
+          cargo test --locked -p pecos-llvm --release
+          cargo test --locked -p pecos-qis --no-default-features --features=llvm --release
+          cargo test --locked -p pecos-hugr-qis --release

Justfile

@@ -71,11 +71,9 @@ ci-env: _msvc-bootstrap
             {{pecos}} llvm configure "$(brew --prefix llvm@21)"
             ;;
         Windows*|MINGW*|MSYS*|CYGWIN*)
-            if ! {{pecos}} llvm find >/dev/null 2>&1; then
-                LLVM_PREFIX="${USERPROFILE:-$HOME}\\.pecos\\deps\\llvm-21.1"
-                powershell.exe -NoProfile -ExecutionPolicy Bypass -File scripts/ci/install-llvm-21-windows.ps1 -InstallDir "$LLVM_PREFIX" -Version "$LLVM_RELEASE_VERSION"
-            fi
-            {{pecos}} llvm configure
+            LLVM_PREFIX="${USERPROFILE:-$HOME}\\.pecos\\deps\\llvm-21.1"
+            powershell.exe -NoProfile -ExecutionPolicy Bypass -File scripts/ci/install-llvm-21-windows.ps1 -InstallDir "$LLVM_PREFIX" -Version "$LLVM_RELEASE_VERSION"
+            {{pecos}} llvm configure "$LLVM_PREFIX"
             ;;
         *)
             {{pecos}} llvm ensure --managed --no-configure

scripts/ci/install-llvm-21-windows.ps1

@@ -19,6 +19,7 @@ $RequiredVersion = "21.1"
 $Asset = "clang+llvm-$Version-x86_64-pc-windows-msvc.tar.xz"
 $Url = "https://github.com/llvm/llvm-project/releases/download/llvmorg-$Version/$Asset"
 $LlvmConfig = Join-Path $InstallDir "bin\llvm-config.exe"
+$LlvmConfigReal = Join-Path $InstallDir "bin\llvm-config.real.exe"
 
 function Find-SevenZip {
     foreach ($Name in @("7z.exe", "7zz.exe", "7za.exe")) {
@@ -66,9 +67,44 @@ function Get-Sha256Hex {
     }
 }
 
+function Install-LlvmConfigWrapper {
+    $WrapperSource = Join-Path $PSScriptRoot "llvm-config-wrapper.rs"
+    if (-not (Test-Path $WrapperSource)) {
+        throw "LLVM config wrapper source not found: $WrapperSource"
+    }
+
+    if (-not (Test-Path $LlvmConfigReal)) {
+        if (-not (Test-Path $LlvmConfig)) {
+            throw "llvm-config.exe not found at $LlvmConfig"
+        }
+        Move-Item -Force -Path $LlvmConfig -Destination $LlvmConfigReal
+    }
+    elseif (Test-Path $LlvmConfig) {
+        Remove-Item -Force $LlvmConfig
+    }
+
+    $Rustc = Get-Command rustc.exe -ErrorAction SilentlyContinue
+    if (-not $Rustc) {
+        throw "rustc.exe is required to repair the LLVM Windows llvm-config system library output"
+    }
+
+    Write-Host "Installing PECOS llvm-config wrapper"
+    & $Rustc.Source --edition=2021 -O -o $LlvmConfig $WrapperSource
+    if ($LASTEXITCODE -ne 0) {
+        throw "rustc failed to build llvm-config wrapper with exit code $LASTEXITCODE"
+    }
+
+    $SystemLibs = (& $LlvmConfig --system-libs --link-static).Trim()
+    $Libxml2Static = Join-Path $InstallDir "lib\libxml2s.lib"
+    if ((-not (Test-Path $Libxml2Static)) -and $SystemLibs -match "(^|\s)libxml2s\.lib($|\s)") {
+        throw "LLVM config wrapper did not filter missing libxml2s.lib from --system-libs"
+    }
+}
+
 if (Test-Path $LlvmConfig) {
     $FoundVersion = (& $LlvmConfig --version).Trim()
     if ($FoundVersion.StartsWith($RequiredVersion)) {
+        Install-LlvmConfigWrapper
         Write-Host "LLVM $FoundVersion already installed at $InstallDir"
         exit 0
     }
@@ -134,6 +170,7 @@ try {
 
     & $LlvmConfig --version
     & $LlvmConfig --shared-mode
+    Install-LlvmConfigWrapper
     Write-Host "Installed LLVM $Version to $InstallDir"
 }
 finally {

scripts/ci/llvm-config-wrapper.rs

@@ -0,0 +1,70 @@
+use std::env;
+use std::io::{self, Write};
+use std::path::Path;
+use std::process::{Command, ExitCode};
+
+fn llvm_lib_exists(current_exe: &Path, lib_name: &str) -> bool {
+    let Some(bin_dir) = current_exe.parent() else {
+        return false;
+    };
+    let Some(prefix_dir) = bin_dir.parent() else {
+        return false;
+    };
+    prefix_dir.join("lib").join(lib_name).exists()
+}
+
+fn filter_system_libs(current_exe: &Path, stdout: &[u8]) -> Vec<u8> {
+    let output = String::from_utf8_lossy(stdout);
+    let mut filtered = output
+        .split_whitespace()
+        .filter(|token| {
+            !token.eq_ignore_ascii_case("libxml2s.lib") || llvm_lib_exists(current_exe, token)
+        })
+        .collect::<Vec<_>>()
+        .join(" ");
+
+    if output.ends_with('\n') {
+        filtered.push('\n');
+    }
+    filtered.into_bytes()
+}
+
+fn main() -> ExitCode {
+    let args = env::args_os().skip(1).collect::<Vec<_>>();
+    let current_exe = match env::current_exe() {
+        Ok(path) => path,
+        Err(error) => {
+            let _ = writeln!(
+                io::stderr(),
+                "failed to locate llvm-config wrapper: {error}"
+            );
+            return ExitCode::FAILURE;
+        }
+    };
+    let real_config = current_exe.with_file_name("llvm-config.real.exe");
+    let output = match Command::new(&real_config).args(&args).output() {
+        Ok(output) => output,
+        Err(error) => {
+            let _ = writeln!(
+                io::stderr(),
+                "failed to run {}: {error}",
+                real_config.display()
+            );
+            return ExitCode::FAILURE;
+        }
+    };
+
+    let _ = io::stderr().write_all(&output.stderr);
+    let is_system_libs = args.iter().any(|arg| arg == "--system-libs");
+    let stdout = if is_system_libs && output.status.success() {
+        filter_system_libs(&current_exe, &output.stdout)
+    } else {
+        output.stdout
+    };
+    let _ = io::stdout().write_all(&stdout);
+
+    match output.status.code() {
+        Some(code) if (0..=255).contains(&code) => ExitCode::from(code as u8),
+        Some(_) | None => ExitCode::FAILURE,
+    }
+}