rustc_codegen_llvm: use safe references for Pass.

Author: irinagpopa

src/librustc_codegen_llvm/back/lto.rs

@@ -468,8 +468,7 @@ fn run_pass_manager(cgcx: &CodegenContext,
 
         if config.verify_llvm_ir {
             let pass = llvm::LLVMRustFindAndCreatePass("verify\0".as_ptr() as *const _);
-            assert!(!pass.is_null());
-            llvm::LLVMRustAddPass(pm, pass);
+            llvm::LLVMRustAddPass(pm, pass.unwrap());
         }
 
         // When optimizing for LTO we don't actually pass in `-O0`, but we force
@@ -503,8 +502,7 @@ fn run_pass_manager(cgcx: &CodegenContext,
 
         if config.verify_llvm_ir {
             let pass = llvm::LLVMRustFindAndCreatePass("verify\0".as_ptr() as *const _);
-            assert!(!pass.is_null());
-            llvm::LLVMRustAddPass(pm, pass);
+            llvm::LLVMRustAddPass(pm, pass.unwrap());
         }
 
         time_ext(cgcx.time_passes, None, "LTO passes", ||

src/librustc_codegen_llvm/back/write.rs

@@ -522,10 +522,10 @@ unsafe fn optimize(cgcx: &CodegenContext,
         // manager.
         let addpass = |pass_name: &str| {
             let pass_name = CString::new(pass_name).unwrap();
-            let pass = llvm::LLVMRustFindAndCreatePass(pass_name.as_ptr());
-            if pass.is_null() {
-                return false;
-            }
+            let pass = match llvm::LLVMRustFindAndCreatePass(pass_name.as_ptr()) {
+                Some(pass) => pass,
+                None => return false,
+            };
             let pass_manager = match llvm::LLVMRustPassKind(pass) {
                 llvm::PassKind::Function => fpm,
                 llvm::PassKind::Module => mpm,

src/librustc_codegen_llvm/llvm/ffi.rs

@@ -397,7 +397,6 @@ extern { pub type ObjectFile; }
 extern { pub type SectionIterator; }
 pub type SectionIteratorRef = *mut SectionIterator;
 extern { pub type Pass; }
-pub type PassRef = *mut Pass;
 extern { pub type TargetMachine; }
 pub type TargetMachineRef = *const TargetMachine;
 extern { pub type Archive; }
@@ -1414,9 +1413,9 @@ extern "C" {
     pub fn LLVMIsAConstantInt(value_ref: &Value) -> Option<&Value>;
     pub fn LLVMIsAConstantFP(value_ref: &Value) -> Option<&Value>;
 
-    pub fn LLVMRustPassKind(Pass: PassRef) -> PassKind;
-    pub fn LLVMRustFindAndCreatePass(Pass: *const c_char) -> PassRef;
-    pub fn LLVMRustAddPass(PM: PassManagerRef, Pass: PassRef);
+    pub fn LLVMRustPassKind(Pass: &Pass) -> PassKind;
+    pub fn LLVMRustFindAndCreatePass(Pass: *const c_char) -> Option<&'static mut Pass>;
+    pub fn LLVMRustAddPass(PM: PassManagerRef, Pass: &'static mut Pass);
 
     pub fn LLVMRustHasFeature(T: TargetMachineRef, s: *const c_char) -> bool;