From fd955605120566b583a4f70829cffdda0dda3972 Mon Sep 17 00:00:00 2001
From: David CARLIER <devnexen@gmail.com>
Date: Fri, 17 Mar 2023 15:00:54 +0000
Subject: [PATCH] Check for the presence of clang frontends. (#1158)

* checks the presence of clang frontends.

close GH-1149.

* fix clippy complaints
---
 libafl_cc/build.rs | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/libafl_cc/build.rs b/libafl_cc/build.rs
index ef5ede4ba1..8d44951936 100644
--- a/libafl_cc/build.rs
+++ b/libafl_cc/build.rs
@@ -205,6 +205,22 @@ pub const LIBAFL_CC_LLVM_VERSION: Option<usize> = None;
         return;
     }
 
+    let llvm_bindir = exec_llvm_config(&["--bindir"]);
+    let bindir_path = Path::new(&llvm_bindir);
+
+    let clang = bindir_path.join("clang");
+    let clangcpp = bindir_path.join("clang++");
+
+    if !clang.exists() {
+        println!("cargo:warning=Failed to find clang frontend.");
+        return;
+    }
+
+    if !clangcpp.exists() {
+        println!("cargo:warning=Failed to find clang++ frontend.");
+        return;
+    }
+
     let cxxflags = exec_llvm_config(&["--cxxflags"]);
     let mut cxxflags: Vec<String> = cxxflags.split_whitespace().map(String::from).collect();
 
@@ -226,32 +242,24 @@ pub const LIBAFL_CC_LLVM_VERSION: Option<usize> = None;
         }
     }
 
-    let llvm_bindir = exec_llvm_config(&["--bindir"]);
-    let bindir_path = Path::new(&llvm_bindir);
-
     write!(
         clang_constants_file,
         "// These constants are autogenerated by build.rs
 
         /// The path to the `clang` executable
-        pub const CLANG_PATH: &str = {:?};
+        pub const CLANG_PATH: &str = {clang:?};
         /// The path to the `clang++` executable
-        pub const CLANGXX_PATH: &str = {:?};
+        pub const CLANGXX_PATH: &str = {clangcpp:?};
 
         /// The size of the edges map
-        pub const EDGES_MAP_SIZE: usize = {};
+        pub const EDGES_MAP_SIZE: usize = {edges_map_size};
 
         /// The size of the accounting maps
-        pub const ACCOUNTING_MAP_SIZE: usize = {};
+        pub const ACCOUNTING_MAP_SIZE: usize = {acc_map_size};
 
         /// The llvm version used to build llvm passes
-        pub const LIBAFL_CC_LLVM_VERSION: Option<usize> = {:?};
+        pub const LIBAFL_CC_LLVM_VERSION: Option<usize> = {llvm_version:?};
         ",
-        bindir_path.join("clang"),
-        bindir_path.join("clang++"),
-        edges_map_size,
-        acc_map_size,
-        llvm_version,
     )
     .expect("Could not write file");