Add a subtype to PassManager to prevent it from being run on the

incorrect type which would have led to a memory error

Author: TheDan64

examples/kaleidoscope/main.rs

@@ -840,7 +840,7 @@ impl<'a> Parser<'a> {
 pub struct Compiler<'a> {
     pub context: &'a Context,
     pub builder: &'a Builder,
-    pub fpm: &'a PassManager,
+    pub fpm: &'a PassManager<FunctionValue>,
     pub module: &'a Module,
     pub function: &'a Function,
 
@@ -1146,7 +1146,7 @@ impl<'a> Compiler<'a> {
 
         // return the whole thing after verification and optimization
         if function.verify(true) {
-            self.fpm.run_on_function(&function);
+            self.fpm.run_on(&function);
 
             Ok(function)
         } else {
@@ -1159,7 +1159,7 @@ impl<'a> Compiler<'a> {
     }
 
     /// Compiles the specified `Function` in the given `Context` and using the specified `Builder`, `PassManager`, and `Module`.
-    pub fn compile(context: &'a Context, builder: &'a Builder, pass_manager: &'a PassManager, module: &'a Module, function: &Function) -> Result<FunctionValue, &'static str> {
+    pub fn compile(context: &'a Context, builder: &'a Builder, pass_manager: &'a PassManager<FunctionValue>, module: &'a Module, function: &Function) -> Result<FunctionValue, &'static str> {
         let mut compiler = Compiler {
             context: context,
             builder: builder,
@@ -1228,7 +1228,7 @@ pub fn main() {
     let builder = context.create_builder();
 
     // Create FPM
-    let fpm = PassManager::create_for_function(&module);
+    let fpm = PassManager::create(&module);
 
     fpm.add_instruction_combining_pass();
     fpm.add_reassociate_pass();

src/builder.rs

@@ -1,3 +1,5 @@
+//! A `Builder` enables you to build instructions.
+
 use either::{Either, Left, Right};
 use llvm_sys::core::{LLVMBuildAdd, LLVMBuildAlloca, LLVMBuildAnd, LLVMBuildArrayAlloca, LLVMBuildArrayMalloc, LLVMBuildBr, LLVMBuildCall, LLVMBuildCast, LLVMBuildCondBr, LLVMBuildExtractValue, LLVMBuildFAdd, LLVMBuildFCmp, LLVMBuildFDiv, LLVMBuildFence, LLVMBuildFMul, LLVMBuildFNeg, LLVMBuildFree, LLVMBuildFSub, LLVMBuildGEP, LLVMBuildICmp, LLVMBuildInsertValue, LLVMBuildIsNotNull, LLVMBuildIsNull, LLVMBuildLoad, LLVMBuildMalloc, LLVMBuildMul, LLVMBuildNeg, LLVMBuildNot, LLVMBuildOr, LLVMBuildPhi, LLVMBuildPointerCast, LLVMBuildRet, LLVMBuildRetVoid, LLVMBuildStore, LLVMBuildSub, LLVMBuildUDiv, LLVMBuildUnreachable, LLVMBuildXor, LLVMDisposeBuilder, LLVMGetElementType, LLVMGetInsertBlock, LLVMGetReturnType, LLVMGetTypeKind, LLVMInsertIntoBuilder, LLVMPositionBuilderAtEnd, LLVMTypeOf, LLVMBuildExtractElement, LLVMBuildInsertElement, LLVMBuildIntToPtr, LLVMBuildPtrToInt, LLVMInsertIntoBuilderWithName, LLVMClearInsertionPosition, LLVMCreateBuilder, LLVMPositionBuilder, LLVMPositionBuilderBefore, LLVMBuildAggregateRet, LLVMBuildStructGEP, LLVMBuildInBoundsGEP, LLVMBuildPtrDiff, LLVMBuildNSWAdd, LLVMBuildNUWAdd, LLVMBuildNSWSub, LLVMBuildNUWSub, LLVMBuildNSWMul, LLVMBuildNUWMul, LLVMBuildSDiv, LLVMBuildSRem, LLVMBuildURem, LLVMBuildFRem, LLVMBuildNSWNeg, LLVMBuildNUWNeg, LLVMBuildFPToUI, LLVMBuildFPToSI, LLVMBuildSIToFP, LLVMBuildUIToFP, LLVMBuildFPTrunc, LLVMBuildFPExt, LLVMBuildIntCast, LLVMBuildFPCast, LLVMBuildSExtOrBitCast, LLVMBuildZExtOrBitCast, LLVMBuildTruncOrBitCast, LLVMBuildSwitch, LLVMAddCase, LLVMBuildShl, LLVMBuildAShr, LLVMBuildLShr, LLVMBuildGlobalString, LLVMBuildGlobalStringPtr, LLVMBuildExactSDiv, LLVMBuildTrunc, LLVMBuildSExt, LLVMBuildZExt, LLVMBuildSelect, LLVMBuildAddrSpaceCast, LLVMBuildBitCast, LLVMBuildShuffleVector, LLVMBuildVAArg, LLVMBuildIndirectBr, LLVMAddDestination};
 use llvm_sys::prelude::{LLVMBuilderRef, LLVMValueRef};
@@ -17,7 +19,7 @@ pub struct Builder {
 
 impl Builder {
     pub(crate) fn new(builder: LLVMBuilderRef) -> Self {
-        assert!(!builder.is_null());
+        debug_assert!(!builder.is_null());
 
         Builder {
             builder: builder
@@ -397,7 +399,7 @@ impl Builder {
             },
             None => unsafe {
                 LLVMInsertIntoBuilder(self.builder, instruction.as_value_ref());
-            }
+            },
         }
     }
 

src/passes.rs

@@ -14,6 +14,9 @@ use crate::module::Module;
 use crate::targets::TargetData;
 use crate::values::{AsValueRef, FunctionValue};
 
+use std::borrow::Borrow;
+use std::marker::PhantomData;
+
 // REVIEW: Opt Level might be identical to targets::Option<CodeGenOptLevel>
 #[derive(Debug)]
 pub struct PassManagerBuilder {
@@ -74,22 +77,72 @@ impl PassManagerBuilder {
         }
     }
 
-    // SubType: pass_manager: &PassManager<FunctionValue>
-    pub fn populate_function_pass_manager(&self, pass_manager: &PassManager) {
+    /// Populates a PassManager<FunctionValue> with the expectation of function
+    /// transformations.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use inkwell::OptimizationLevel::Aggressive;
+    /// use inkwell::module::Module;
+    /// use inkwell::passes::{PassManager, PassManagerBuilder};
+    ///
+    /// let module = Module::create("mod");
+    /// let pass_manager_builder = PassManagerBuilder::create();
+    ///
+    /// pass_manager_builder.set_optimization_level(Aggressive);
+    ///
+    /// let fpm = PassManager::create(&module);
+    ///
+    /// pass_manager_builder.populate_function_pass_manager(&fpm);
+    /// ```
+    pub fn populate_function_pass_manager(&self, pass_manager: &PassManager<FunctionValue>) {
         unsafe {
             LLVMPassManagerBuilderPopulateFunctionPassManager(self.pass_manager_builder, pass_manager.pass_manager)
         }
     }
 
-    // SubType: pass_manager: &PassManager<Module>
-    pub fn populate_module_pass_manager(&self, pass_manager: &PassManager) {
+    /// Populates a PassManager<Module> with the expectation of whole module
+    /// transformations.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use inkwell::OptimizationLevel::Aggressive;
+    /// use inkwell::passes::{PassManager, PassManagerBuilder};
+    ///
+    /// let pass_manager_builder = PassManagerBuilder::create();
+    ///
+    /// pass_manager_builder.set_optimization_level(Aggressive);
+    ///
+    /// let fpm = PassManager::create(());
+    ///
+    /// pass_manager_builder.populate_module_pass_manager(&fpm);
+    /// ```
+    pub fn populate_module_pass_manager(&self, pass_manager: &PassManager<Module>) {
         unsafe {
             LLVMPassManagerBuilderPopulateModulePassManager(self.pass_manager_builder, pass_manager.pass_manager)
         }
     }
 
-    // SubType: Need LTO subtype?
-    pub fn populate_lto_pass_manager(&self, pass_manager: &PassManager, internalize: bool, run_inliner: bool) {
+    /// Populates a PassManager<Module> with the expectation of link time
+    /// optimization transformations.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use inkwell::OptimizationLevel::Aggressive;
+    /// use inkwell::passes::{PassManager, PassManagerBuilder};
+    ///
+    /// let pass_manager_builder = PassManagerBuilder::create();
+    ///
+    /// pass_manager_builder.set_optimization_level(Aggressive);
+    ///
+    /// let lpm = PassManager::create(());
+    ///
+    /// pass_manager_builder.populate_lto_pass_manager(&lpm, false, false);
+    /// ```
+    pub fn populate_lto_pass_manager(&self, pass_manager: &PassManager<Module>, internalize: bool, run_inliner: bool) {
         unsafe {
             LLVMPassManagerBuilderPopulateLTOPassManager(self.pass_manager_builder, pass_manager.pass_manager, internalize as i32, run_inliner as i32)
         }
@@ -104,37 +157,65 @@ impl Drop for PassManagerBuilder {
     }
 }
 
+// This is an ugly privacy hack so that PassManagerSubType can stay private
+// to this module and so that super traits using this trait will be not be
+// implementable outside this library
+pub trait PassManagerSubType {
+    type Input;
+
+    unsafe fn create<I: Borrow<Self::Input>>(input: I) -> LLVMPassManagerRef;
+    unsafe fn run_in_pass_manager(&self, pass_manager: &PassManager<Self>) -> bool where Self: Sized;
+}
+
+impl PassManagerSubType for Module {
+    type Input = ();
+
+    unsafe fn create<I: Borrow<Self::Input>>(_: I) -> LLVMPassManagerRef {
+        LLVMCreatePassManager()
+    }
+
+    unsafe fn run_in_pass_manager(&self, pass_manager: &PassManager<Self>) -> bool {
+        LLVMRunPassManager(pass_manager.pass_manager, self.module.get()) == 1
+    }
+}
+
+// With GATs https://github.com/rust-lang/rust/issues/44265 this could be
+// type Input<'a> = &'a Module;
+impl PassManagerSubType for FunctionValue {
+    type Input = Module;
+
+    unsafe fn create<I: Borrow<Self::Input>>(input: I) -> LLVMPassManagerRef {
+        LLVMCreateFunctionPassManagerForModule(input.borrow().module.get())
+    }
+
+    unsafe fn run_in_pass_manager(&self, pass_manager: &PassManager<Self>) -> bool {
+        LLVMRunFunctionPassManager(pass_manager.pass_manager, self.as_value_ref()) == 1
+    }
+}
+
 // SubTypes: PassManager<Module>, PassManager<FunctionValue>
 /// A manager for running optimization and simplification passes. Much of the
 /// documenation for specific passes is directly from the [LLVM
 /// documentation](https://llvm.org/docs/Passes.html).
 #[derive(Debug)]
-pub struct PassManager {
+pub struct PassManager<T> {
     pub(crate) pass_manager: LLVMPassManagerRef,
+    sub_type: PhantomData<T>,
 }
 
-impl PassManager {
-    pub(crate) fn new(pass_manager: LLVMPassManagerRef) -> PassManager {
+impl<T: PassManagerSubType> PassManager<T> {
+    pub(crate) fn new(pass_manager: LLVMPassManagerRef) -> Self {
         assert!(!pass_manager.is_null());
 
         PassManager {
             pass_manager,
+            sub_type: PhantomData,
         }
     }
 
-    // SubTypes: PassManager<Module>::create()
-    pub fn create_for_module() -> Self {
-        let pass_manager = unsafe {
-            LLVMCreatePassManager()
-        };
-
-        PassManager::new(pass_manager)
-    }
-
-    // SubTypes: PassManager<FunctionValue>::create()
-    pub fn create_for_function(module: &Module) -> Self {
+    pub fn create<I: Borrow<T::Input>>(input: I) -> PassManager<T> {
         let pass_manager = unsafe {
-            LLVMCreateFunctionPassManagerForModule(module.module.get())
+            T::create(input)
         };
 
         PassManager::new(pass_manager)
@@ -153,17 +234,11 @@ impl PassManager {
         }
     }
 
-    // SubTypes: For PassManager<FunctionValue> only, rename run_on
-    pub fn run_on_function(&self, fn_value: &FunctionValue) -> bool {
-        unsafe {
-            LLVMRunFunctionPassManager(self.pass_manager, fn_value.as_value_ref()) == 1
-        }
-    }
-
-    // SubTypes: For PassManager<Module> only, rename run_on
-    pub fn run_on_module(&self, module: &Module) -> bool {
+    /// This method returns true if any of the passes modified the module and
+    /// false otherwise.
+    pub fn run_on(&self, input: &T) -> bool {
         unsafe {
-            LLVMRunPassManager(self.pass_manager, module.module.get()) == 1
+            input.run_in_pass_manager(self)
         }
     }
 
@@ -984,7 +1059,7 @@ impl PassManager {
     }
 }
 
-impl Drop for PassManager {
+impl<T> Drop for PassManager<T> {
     fn drop(&mut self) {
         unsafe {
             LLVMDisposePassManager(self.pass_manager)

src/targets.rs

@@ -914,7 +914,7 @@ impl TargetMachine {
     }
 
     // TODO: Move to PassManager?
-    pub fn add_analysis_passes(&self, pass_manager: &PassManager) {
+    pub fn add_analysis_passes<T>(&self, pass_manager: &PassManager<T>) {
         unsafe {
             LLVMAddAnalysisPasses(self.target_machine, pass_manager.pass_manager)
         }

tests/all/test_passes.rs

@@ -1,14 +1,14 @@
 extern crate inkwell;
 
+use self::inkwell::OptimizationLevel::Aggressive;
 use self::inkwell::context::Context;
 use self::inkwell::passes::{PassManagerBuilder, PassManager, PassRegistry};
-use self::inkwell::OptimizationLevel::Aggressive;
 
 #[test]
 fn test_init_all_passes_for_module() {
     let context = Context::create();
     let module = context.create_module("my_module");
-    let pass_manager = PassManager::create_for_module();
+    let pass_manager = PassManager::create(());
 
     pass_manager.add_argument_promotion_pass();
     pass_manager.add_constant_merge_pass();
@@ -85,7 +85,7 @@ fn test_init_all_passes_for_module() {
     assert!(!pass_manager.initialize());
     assert!(!pass_manager.finalize());
 
-    pass_manager.run_on_module(&module);
+    pass_manager.run_on(&module);
 
     assert!(!pass_manager.initialize());
     assert!(!pass_manager.finalize());
@@ -107,7 +107,7 @@ fn test_pass_manager_builder() {
     let context = Context::create();
     let module = context.create_module("my_module");
 
-    let fn_pass_manager = PassManager::create_for_function(&module);
+    let fn_pass_manager = PassManager::create(&module);
 
     pass_manager_builder.populate_function_pass_manager(&fn_pass_manager);
 
@@ -123,20 +123,30 @@ fn test_pass_manager_builder() {
     // TODO: Test with actual changes? Would be true in that case
     // REVIEW: Segfaults in 4.0
     #[cfg(not(feature = "llvm4-0"))]
-    assert!(!fn_pass_manager.run_on_function(&fn_value));
+    assert!(!fn_pass_manager.run_on(&fn_value));
 
-    let module_pass_manager = PassManager::create_for_module();
+    let module_pass_manager = PassManager::create(());
 
     pass_manager_builder.populate_module_pass_manager(&module_pass_manager);
 
+    let module2 = module.clone();
+
     // TODOC: Seems to return true in 3.7, 6.0, & 7.0 even though no changes were made.
     // In 3.6, 3.8, & 3.9 it returns false. Seems like a LLVM bug?
     #[cfg(not(any(feature = "llvm3-7", feature = "llvm6-0", feature = "llvm7-0")))]
-    assert!(!module_pass_manager.run_on_module(&module));
+    assert!(!module_pass_manager.run_on(&module));
     #[cfg(any(feature = "llvm3-7", feature = "llvm6-0", feature = "llvm7-0"))]
-    assert!(module_pass_manager.run_on_module(&module));
+    assert!(module_pass_manager.run_on(&module));
+
+    let lto_pass_manager = PassManager::create(());
 
-    // TODO: Populate LTO pass manager?
+    pass_manager_builder.populate_lto_pass_manager(&lto_pass_manager, false, false);
+
+    // See above note on version differences
+    #[cfg(not(any(feature = "llvm3-7", feature = "llvm6-0", feature = "llvm7-0")))]
+    assert!(!lto_pass_manager.run_on(&module2));
+    #[cfg(any(feature = "llvm3-7", feature = "llvm6-0", feature = "llvm7-0"))]
+    assert!(lto_pass_manager.run_on(&module2));
 }
 
 #[test]