Auto merge of #113722 - bjorn3:allocator_shim_refactor, r=jackh726

Extract a create_wrapper_function for use in allocator shim writing

This deduplicates some logic and makes it easier to follow what wrappers are produced. In the future it may allow moving the code to determine which wrappers to create to cg_ssa.

Author: bors

compiler/rustc_codegen_llvm/src/allocator.rs

@@ -9,7 +9,7 @@ use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{DebugInfo, OomStrategy};
 
 use crate::debuginfo;
-use crate::llvm::{self, False, True};
+use crate::llvm::{self, Context, False, Module, True, Type};
 use crate::ModuleLlvm;
 
 pub(crate) unsafe fn codegen(
@@ -29,7 +29,6 @@ pub(crate) unsafe fn codegen(
     };
     let i8 = llvm::LLVMInt8TypeInContext(llcx);
     let i8p = llvm::LLVMPointerTypeInContext(llcx, 0);
-    let void = llvm::LLVMVoidTypeInContext(llcx);
 
     if kind == AllocatorKind::Default {
         for method in ALLOCATOR_METHODS {
@@ -54,102 +53,25 @@ pub(crate) unsafe fn codegen(
                     panic!("invalid allocator output")
                 }
             };
-            let ty = llvm::LLVMFunctionType(
-                output.unwrap_or(void),
-                args.as_ptr(),
-                args.len() as c_uint,
-                False,
-            );
-            let name = global_fn_name(method.name);
-            let llfn =
-                llvm::LLVMRustGetOrInsertFunction(llmod, name.as_ptr().cast(), name.len(), ty);
-
-            if tcx.sess.target.default_hidden_visibility {
-                llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
-            }
-            if tcx.sess.must_emit_unwind_tables() {
-                let uwtable = attributes::uwtable_attr(llcx);
-                attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[uwtable]);
-            }
 
-            let callee = default_fn_name(method.name);
-            let callee =
-                llvm::LLVMRustGetOrInsertFunction(llmod, callee.as_ptr().cast(), callee.len(), ty);
-            llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden);
-
-            let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, "entry\0".as_ptr().cast());
-
-            let llbuilder = llvm::LLVMCreateBuilderInContext(llcx);
-            llvm::LLVMPositionBuilderAtEnd(llbuilder, llbb);
-            let args = args
-                .iter()
-                .enumerate()
-                .map(|(i, _)| llvm::LLVMGetParam(llfn, i as c_uint))
-                .collect::<Vec<_>>();
-            let ret = llvm::LLVMRustBuildCall(
-                llbuilder,
-                ty,
-                callee,
-                args.as_ptr(),
-                args.len() as c_uint,
-                [].as_ptr(),
-                0 as c_uint,
-            );
-            llvm::LLVMSetTailCall(ret, True);
-            if output.is_some() {
-                llvm::LLVMBuildRet(llbuilder, ret);
-            } else {
-                llvm::LLVMBuildRetVoid(llbuilder);
-            }
-            llvm::LLVMDisposeBuilder(llbuilder);
+            let from_name = global_fn_name(method.name);
+            let to_name = default_fn_name(method.name);
+
+            create_wrapper_function(tcx, llcx, llmod, &from_name, &to_name, &args, output, false);
         }
     }
 
     // rust alloc error handler
-    let args = [usize, usize]; // size, align
-
-    let ty = llvm::LLVMFunctionType(void, args.as_ptr(), args.len() as c_uint, False);
-    let name = "__rust_alloc_error_handler";
-    let llfn = llvm::LLVMRustGetOrInsertFunction(llmod, name.as_ptr().cast(), name.len(), ty);
-    // -> ! DIFlagNoReturn
-    let no_return = llvm::AttributeKind::NoReturn.create_attr(llcx);
-    attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[no_return]);
-
-    if tcx.sess.target.default_hidden_visibility {
-        llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
-    }
-    if tcx.sess.must_emit_unwind_tables() {
-        let uwtable = attributes::uwtable_attr(llcx);
-        attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[uwtable]);
-    }
-
-    let callee = alloc_error_handler_name(alloc_error_handler_kind);
-    let callee = llvm::LLVMRustGetOrInsertFunction(llmod, callee.as_ptr().cast(), callee.len(), ty);
-    // -> ! DIFlagNoReturn
-    attributes::apply_to_llfn(callee, llvm::AttributePlace::Function, &[no_return]);
-    llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden);
-
-    let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, "entry\0".as_ptr().cast());
-
-    let llbuilder = llvm::LLVMCreateBuilderInContext(llcx);
-    llvm::LLVMPositionBuilderAtEnd(llbuilder, llbb);
-    let args = args
-        .iter()
-        .enumerate()
-        .map(|(i, _)| llvm::LLVMGetParam(llfn, i as c_uint))
-        .collect::<Vec<_>>();
-    let ret = llvm::LLVMRustBuildCall(
-        llbuilder,
-        ty,
-        callee,
-        args.as_ptr(),
-        args.len() as c_uint,
-        [].as_ptr(),
-        0 as c_uint,
+    create_wrapper_function(
+        tcx,
+        llcx,
+        llmod,
+        "__rust_alloc_error_handler",
+        &alloc_error_handler_name(alloc_error_handler_kind),
+        &[usize, usize], // size, align
+        None,
+        true,
     );
-    llvm::LLVMSetTailCall(ret, True);
-    llvm::LLVMBuildRetVoid(llbuilder);
-    llvm::LLVMDisposeBuilder(llbuilder);
 
     // __rust_alloc_error_handler_should_panic
     let name = OomStrategy::SYMBOL;
@@ -175,3 +97,79 @@ pub(crate) unsafe fn codegen(
         dbg_cx.finalize(tcx.sess);
     }
 }
+
+fn create_wrapper_function(
+    tcx: TyCtxt<'_>,
+    llcx: &Context,
+    llmod: &Module,
+    from_name: &str,
+    to_name: &str,
+    args: &[&Type],
+    output: Option<&Type>,
+    no_return: bool,
+) {
+    unsafe {
+        let ty = llvm::LLVMFunctionType(
+            output.unwrap_or_else(|| llvm::LLVMVoidTypeInContext(llcx)),
+            args.as_ptr(),
+            args.len() as c_uint,
+            False,
+        );
+        let llfn = llvm::LLVMRustGetOrInsertFunction(
+            llmod,
+            from_name.as_ptr().cast(),
+            from_name.len(),
+            ty,
+        );
+        let no_return = if no_return {
+            // -> ! DIFlagNoReturn
+            let no_return = llvm::AttributeKind::NoReturn.create_attr(llcx);
+            attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[no_return]);
+            Some(no_return)
+        } else {
+            None
+        };
+
+        if tcx.sess.target.default_hidden_visibility {
+            llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
+        }
+        if tcx.sess.must_emit_unwind_tables() {
+            let uwtable = attributes::uwtable_attr(llcx);
+            attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[uwtable]);
+        }
+
+        let callee =
+            llvm::LLVMRustGetOrInsertFunction(llmod, to_name.as_ptr().cast(), to_name.len(), ty);
+        if let Some(no_return) = no_return {
+            // -> ! DIFlagNoReturn
+            attributes::apply_to_llfn(callee, llvm::AttributePlace::Function, &[no_return]);
+        }
+        llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden);
+
+        let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, "entry\0".as_ptr().cast());
+
+        let llbuilder = llvm::LLVMCreateBuilderInContext(llcx);
+        llvm::LLVMPositionBuilderAtEnd(llbuilder, llbb);
+        let args = args
+            .iter()
+            .enumerate()
+            .map(|(i, _)| llvm::LLVMGetParam(llfn, i as c_uint))
+            .collect::<Vec<_>>();
+        let ret = llvm::LLVMRustBuildCall(
+            llbuilder,
+            ty,
+            callee,
+            args.as_ptr(),
+            args.len() as c_uint,
+            [].as_ptr(),
+            0 as c_uint,
+        );
+        llvm::LLVMSetTailCall(ret, True);
+        if output.is_some() {
+            llvm::LLVMBuildRet(llbuilder, ret);
+        } else {
+            llvm::LLVMBuildRetVoid(llbuilder);
+        }
+        llvm::LLVMDisposeBuilder(llbuilder);
+    }
+}