Merge pull request #306 from bjorn3/extract_helper

Extract a create_wrapper_function for use in allocator shim writing

Author: antoyo

src/allocator.rs

@@ -1,6 +1,6 @@
 #[cfg(feature="master")]
 use gccjit::FnAttribute;
-use gccjit::{FunctionType, GlobalKind, ToRValue};
+use gccjit::{Context, FunctionType, GlobalKind, ToRValue, Type};
 use rustc_ast::expand::allocator::{
     alloc_error_handler_name, default_fn_name, global_fn_name, AllocatorKind, AllocatorTy,
     ALLOCATOR_METHODS, NO_ALLOC_SHIM_IS_UNSTABLE,
@@ -22,7 +22,6 @@ pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, mods: &mut GccContext, _module_nam
         };
     let i8 = context.new_type::<i8>();
     let i8p = i8.make_pointer();
-    let void = context.new_type::<()>();
 
     if kind == AllocatorKind::Default {
         for method in ALLOCATOR_METHODS {
@@ -47,67 +46,62 @@ pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, mods: &mut GccContext, _module_nam
                     panic!("invalid allocator output")
                 }
             };
-            let name = global_fn_name(method.name);
+            let from_name = global_fn_name(method.name);
+            let to_name = default_fn_name(method.name);
 
-            let args: Vec<_> = types.iter().enumerate()
-                .map(|(index, typ)| context.new_parameter(None, *typ, &format!("param{}", index)))
-                .collect();
-            let func = context.new_function(None, FunctionType::Exported, output.unwrap_or(void), &args, name, false);
+            create_wrapper_function(tcx, context, &from_name, &to_name, &types, output);
+        }
+    }
 
-            if tcx.sess.target.options.default_hidden_visibility {
-                #[cfg(feature="master")]
-                func.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Hidden));
-            }
-            if tcx.sess.must_emit_unwind_tables() {
-                // TODO(antoyo): emit unwind tables.
-            }
+    // FIXME(bjorn3): Add noreturn attribute
+    create_wrapper_function(
+        tcx,
+        context,
+        "__rust_alloc_error_handler",
+        &alloc_error_handler_name(alloc_error_handler_kind),
+        &[usize, usize],
+        None,
+    );
 
-            let callee = default_fn_name(method.name);
-            let args: Vec<_> = types.iter().enumerate()
-                .map(|(index, typ)| context.new_parameter(None, *typ, &format!("param{}", index)))
-                .collect();
-            let callee = context.new_function(None, FunctionType::Extern, output.unwrap_or(void), &args, callee, false);
-            #[cfg(feature="master")]
-            callee.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Hidden));
-
-            let block = func.new_block("entry");
-
-            let args = args
-                .iter()
-                .enumerate()
-                .map(|(i, _)| func.get_param(i as i32).to_rvalue())
-                .collect::<Vec<_>>();
-            let ret = context.new_call(None, callee, &args);
-            //llvm::LLVMSetTailCall(ret, True);
-            if output.is_some() {
-                block.end_with_return(None, ret);
-            }
-            else {
-                block.end_with_void_return(None);
-            }
+    let name = OomStrategy::SYMBOL.to_string();
+    let global = context.new_global(None, GlobalKind::Exported, i8, name);
+    let value = tcx.sess.opts.unstable_opts.oom.should_panic();
+    let value = context.new_rvalue_from_int(i8, value as i32);
+    global.global_set_initializer_rvalue(value);
 
-            // TODO(@Commeownist): Check if we need to emit some extra debugging info in certain circumstances
-            // as described in https://github.com/rust-lang/rust/commit/77a96ed5646f7c3ee8897693decc4626fe380643
-        }
-    }
+    let name = NO_ALLOC_SHIM_IS_UNSTABLE.to_string();
+    let global = context.new_global(None, GlobalKind::Exported, i8, name);
+    let value = context.new_rvalue_from_int(i8, 0);
+    global.global_set_initializer_rvalue(value);
+}
+
+fn create_wrapper_function(
+    tcx: TyCtxt<'_>,
+    context: &Context<'_>,
+    from_name: &str,
+    to_name: &str,
+    types: &[Type<'_>],
+    output: Option<Type<'_>>,
+) {
+    let void = context.new_type::<()>();
 
-    let types = [usize, usize];
-    let name = "__rust_alloc_error_handler".to_string();
     let args: Vec<_> = types.iter().enumerate()
         .map(|(index, typ)| context.new_parameter(None, *typ, &format!("param{}", index)))
         .collect();
-    let func = context.new_function(None, FunctionType::Exported, void, &args, name, false);
+    let func = context.new_function(None, FunctionType::Exported, output.unwrap_or(void), &args, from_name, false);
 
-    if tcx.sess.target.default_hidden_visibility {
+    if tcx.sess.target.options.default_hidden_visibility {
         #[cfg(feature="master")]
         func.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Hidden));
     }
+    if tcx.sess.must_emit_unwind_tables() {
+        // TODO(antoyo): emit unwind tables.
+    }
 
-    let callee = alloc_error_handler_name(alloc_error_handler_kind);
     let args: Vec<_> = types.iter().enumerate()
         .map(|(index, typ)| context.new_parameter(None, *typ, &format!("param{}", index)))
         .collect();
-    let callee = context.new_function(None, FunctionType::Extern, void, &args, callee, false);
+    let callee = context.new_function(None, FunctionType::Extern, output.unwrap_or(void), &args, to_name, false);
     #[cfg(feature="master")]
     callee.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Hidden));
 
@@ -118,18 +112,15 @@ pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, mods: &mut GccContext, _module_nam
         .enumerate()
         .map(|(i, _)| func.get_param(i as i32).to_rvalue())
         .collect::<Vec<_>>();
-    let _ret = context.new_call(None, callee, &args);
+    let ret = context.new_call(None, callee, &args);
     //llvm::LLVMSetTailCall(ret, True);
-    block.end_with_void_return(None);
-
-    let name = OomStrategy::SYMBOL.to_string();
-    let global = context.new_global(None, GlobalKind::Exported, i8, name);
-    let value = tcx.sess.opts.unstable_opts.oom.should_panic();
-    let value = context.new_rvalue_from_int(i8, value as i32);
-    global.global_set_initializer_rvalue(value);
+    if output.is_some() {
+        block.end_with_return(None, ret);
+    }
+    else {
+        block.end_with_void_return(None);
+    }
 
-    let name = NO_ALLOC_SHIM_IS_UNSTABLE.to_string();
-    let global = context.new_global(None, GlobalKind::Exported, i8, name);
-    let value = context.new_rvalue_from_int(i8, 0);
-    global.global_set_initializer_rvalue(value);
+    // TODO(@Commeownist): Check if we need to emit some extra debugging info in certain circumstances
+    // as described in https://github.com/rust-lang/rust/commit/77a96ed5646f7c3ee8897693decc4626fe380643
 }