Add support for include directory env vars.

Author: elibol

macro/src/dialect.rs

@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
 mod error;
 mod generation;
 mod input;
@@ -31,7 +36,7 @@ pub fn generate_dialect(input: DialectInput) -> Result<TokenStream, Box<dyn std:
 
     parser = parser.add_include_directory(LLVM_INCLUDE_DIRECTORY);
 
-    for path in input.directories() {
+    let get_path = |path: &str| {
         let path = if matches!(
             Path::new(path).components().next(),
             Some(Component::CurDir | Component::ParentDir)
@@ -40,8 +45,19 @@ pub fn generate_dialect(input: DialectInput) -> Result<TokenStream, Box<dyn std:
         } else {
             Path::new(LLVM_INCLUDE_DIRECTORY).join(path)
         };
+        path.display().to_string()
+    };
+
+    for path in input.directories() {
+        let path = get_path(path);
+        parser = parser.add_include_directory(&path);
+    }
 
-        parser = parser.add_include_directory(&path.display().to_string());
+    for env_var in input.directory_env_vars() {
+        if let Ok(path) = env::var(env_var) {
+            let path = get_path(&path);
+            parser = parser.add_include_directory(&path);
+        }
     }
 
     if input.files().count() > 0 {

macro/src/dialect/input.rs

@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
 mod input_field;
 
 use self::input_field::InputField;
@@ -8,6 +13,7 @@ pub struct DialectInput {
     name: String,
     files: Vec<String>,
     directories: Vec<String>,
+    directory_env_vars: Vec<String>,
 }
 
 impl DialectInput {
@@ -22,13 +28,18 @@ impl DialectInput {
     pub fn directories(&self) -> impl Iterator<Item = &str> {
         self.directories.iter().map(Deref::deref)
     }
+
+    pub fn directory_env_vars(&self) -> impl Iterator<Item = &str> {
+        self.directory_env_vars.iter().map(Deref::deref)
+    }
 }
 
 impl Parse for DialectInput {
     fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
         let mut name = None;
         let mut files = vec![];
         let mut directories = vec![];
+        let mut directory_env_vars = vec![];
 
         for item in Punctuated::<InputField, Token![,]>::parse_terminated(input)? {
             match item {
@@ -39,13 +50,17 @@ impl Parse for DialectInput {
                 InputField::Directories(field) => {
                     directories = field.into_iter().map(|literal| literal.value()).collect()
                 }
+                InputField::DirectoryEnvVars(field) => {
+                    directory_env_vars = field.into_iter().map(|literal| literal.value()).collect()
+                }
             }
         }
 
         Ok(Self {
             name: name.ok_or_else(|| input.error("dialect name required"))?,
             files,
             directories,
+            directory_env_vars
         })
     }
 }

macro/src/dialect/input/input_field.rs

@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
 use proc_macro2::Ident;
 use quote::format_ident;
 use syn::{LitStr, Token, bracketed, parse::Parse, punctuated::Punctuated};
@@ -6,6 +11,7 @@ pub enum InputField {
     Name(LitStr),
     Files(Punctuated<LitStr, Token![,]>),
     Directories(Punctuated<LitStr, Token![,]>),
+    DirectoryEnvVars(Punctuated<LitStr, Token![,]>),
 }
 
 impl Parse for InputField {
@@ -28,6 +34,12 @@ impl Parse for InputField {
             Ok(Self::Directories(
                 Punctuated::<LitStr, Token![,]>::parse_terminated(&content)?,
             ))
+        } else if ident == format_ident!("include_directory_env_vars") {
+            let content;
+            bracketed!(content in input);
+            Ok(Self::DirectoryEnvVars(
+                Punctuated::<LitStr, Token![,]>::parse_terminated(&content)?,
+            ))
         } else {
             Err(input.error(format!("invalid field {ident}")))
         }