Rollup merge of #108783 - antoyo:sync-cg_gcc-2023-03-04, r=cjgillot

Sync rustc_codegen_gcc 2023/03/04

Hi.
This sync all the changes from rustc_codegen_gcc.
Thanks for the review.

compiler/rustc_codegen_gcc/src/intrinsic/mod.rs

@@ -1,6 +1,9 @@
 pub mod llvm;
 mod simd;
 
+#[cfg(feature="master")]
+use std::iter;
+
 use gccjit::{ComparisonOp, Function, RValue, ToRValue, Type, UnaryOp, FunctionType};
 use rustc_codegen_ssa::MemFlags;
 use rustc_codegen_ssa::base::wants_msvc_seh;
@@ -8,15 +11,23 @@ use rustc_codegen_ssa::common::IntPredicate;
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
 use rustc_codegen_ssa::mir::place::PlaceRef;
 use rustc_codegen_ssa::traits::{ArgAbiMethods, BaseTypeMethods, BuilderMethods, ConstMethods, IntrinsicCallMethods};
+#[cfg(feature="master")]
+use rustc_codegen_ssa::traits::{DerivedTypeMethods, MiscMethods};
 use rustc_middle::bug;
 use rustc_middle::ty::{self, Instance, Ty};
 use rustc_middle::ty::layout::LayoutOf;
+#[cfg(feature="master")]
+use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt};
 use rustc_span::{Span, Symbol, symbol::kw, sym};
 use rustc_target::abi::HasDataLayout;
 use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode};
 use rustc_target::spec::PanicStrategy;
+#[cfg(feature="master")]
+use rustc_target::spec::abi::Abi;
 
 use crate::abi::GccType;
+#[cfg(feature="master")]
+use crate::abi::FnAbiGccExt;
 use crate::builder::Builder;
 use crate::common::{SignType, TypeReflection};
 use crate::context::CodegenCx;
@@ -93,7 +104,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
         let name = tcx.item_name(def_id);
         let name_str = name.as_str();
 
-        let llret_ty = self.layout_of(ret_ty).gcc_type(self, true);
+        let llret_ty = self.layout_of(ret_ty).gcc_type(self);
         let result = PlaceRef::new_sized(llresult, fn_abi.ret.layout);
 
         let simple = get_simple_intrinsic(self, name);
@@ -406,7 +417,7 @@ impl<'gcc, 'tcx> ArgAbiExt<'gcc, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
     /// Gets the LLVM type for a place of the original Rust type of
     /// this argument/return, i.e., the result of `type_of::type_of`.
     fn memory_ty(&self, cx: &CodegenCx<'gcc, 'tcx>) -> Type<'gcc> {
-        self.layout.gcc_type(cx, true)
+        self.layout.gcc_type(cx)
     }
 
     /// Stores a direct/indirect value described by this ArgAbi into a
@@ -1122,10 +1133,8 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
     }
 }
 
-fn try_intrinsic<'gcc, 'tcx>(bx: &mut Builder<'_, 'gcc, 'tcx>, try_func: RValue<'gcc>, data: RValue<'gcc>, _catch_func: RValue<'gcc>, dest: RValue<'gcc>) {
-    // NOTE: the `|| true` here is to use the panic=abort strategy with panic=unwind too
-    if bx.sess().panic_strategy() == PanicStrategy::Abort || true {
-        // TODO(bjorn3): Properly implement unwinding and remove the `|| true` once this is done.
+fn try_intrinsic<'a, 'b, 'gcc, 'tcx>(bx: &'b mut Builder<'a, 'gcc, 'tcx>, try_func: RValue<'gcc>, data: RValue<'gcc>, _catch_func: RValue<'gcc>, dest: RValue<'gcc>) {
+    if bx.sess().panic_strategy() == PanicStrategy::Abort {
         bx.call(bx.type_void(), None, try_func, &[data], None);
         // Return 0 unconditionally from the intrinsic call;
         // we can never unwind.
@@ -1136,6 +1145,141 @@ fn try_intrinsic<'gcc, 'tcx>(bx: &mut Builder<'_, 'gcc, 'tcx>, try_func: RValue<
         unimplemented!();
     }
     else {
+        #[cfg(feature="master")]
+        codegen_gnu_try(bx, try_func, data, _catch_func, dest);
+        #[cfg(not(feature="master"))]
         unimplemented!();
     }
 }
+
+// Definition of the standard `try` function for Rust using the GNU-like model
+// of exceptions (e.g., the normal semantics of LLVM's `landingpad` and `invoke`
+// instructions).
+//
+// This codegen is a little surprising because we always call a shim
+// function instead of inlining the call to `invoke` manually here. This is done
+// because in LLVM we're only allowed to have one personality per function
+// definition. The call to the `try` intrinsic is being inlined into the
+// function calling it, and that function may already have other personality
+// functions in play. By calling a shim we're guaranteed that our shim will have
+// the right personality function.
+#[cfg(feature="master")]
+fn codegen_gnu_try<'gcc>(bx: &mut Builder<'_, 'gcc, '_>, try_func: RValue<'gcc>, data: RValue<'gcc>, catch_func: RValue<'gcc>, dest: RValue<'gcc>) {
+    let cx: &CodegenCx<'gcc, '_> = bx.cx;
+    let (llty, func) = get_rust_try_fn(cx, &mut |mut bx| {
+        // Codegens the shims described above:
+        //
+        //   bx:
+        //      invoke %try_func(%data) normal %normal unwind %catch
+        //
+        //   normal:
+        //      ret 0
+        //
+        //   catch:
+        //      (%ptr, _) = landingpad
+        //      call %catch_func(%data, %ptr)
+        //      ret 1
+        let then = bx.append_sibling_block("then");
+        let catch = bx.append_sibling_block("catch");
+
+        let func = bx.current_func();
+        let try_func = func.get_param(0).to_rvalue();
+        let data = func.get_param(1).to_rvalue();
+        let catch_func = func.get_param(2).to_rvalue();
+        let try_func_ty = bx.type_func(&[bx.type_i8p()], bx.type_void());
+
+        let current_block = bx.block.clone();
+
+        bx.switch_to_block(then);
+        bx.ret(bx.const_i32(0));
+
+        // Type indicator for the exception being thrown.
+        //
+        // The value is a pointer to the exception object
+        // being thrown.
+        bx.switch_to_block(catch);
+        bx.set_personality_fn(bx.eh_personality());
+
+        let eh_pointer_builtin = bx.cx.context.get_target_builtin_function("__builtin_eh_pointer");
+        let zero = bx.cx.context.new_rvalue_zero(bx.int_type);
+        let ptr = bx.cx.context.new_call(None, eh_pointer_builtin, &[zero]);
+        let catch_ty = bx.type_func(&[bx.type_i8p(), bx.type_i8p()], bx.type_void());
+        bx.call(catch_ty, None, catch_func, &[data, ptr], None);
+        bx.ret(bx.const_i32(1));
+
+        // NOTE: the blocks must be filled before adding the try/catch, otherwise gcc will not
+        // generate a try/catch.
+        // FIXME(antoyo): add a check in the libgccjit API to prevent this.
+        bx.switch_to_block(current_block);
+        bx.invoke(try_func_ty, None, try_func, &[data], then, catch, None);
+    });
+
+    let func = unsafe { std::mem::transmute(func) };
+
+    // Note that no invoke is used here because by definition this function
+    // can't panic (that's what it's catching).
+    let ret = bx.call(llty, None, func, &[try_func, data, catch_func], None);
+    let i32_align = bx.tcx().data_layout.i32_align.abi;
+    bx.store(ret, dest, i32_align);
+}
+
+
+// Helper function used to get a handle to the `__rust_try` function used to
+// catch exceptions.
+//
+// This function is only generated once and is then cached.
+#[cfg(feature="master")]
+fn get_rust_try_fn<'a, 'gcc, 'tcx>(cx: &'a CodegenCx<'gcc, 'tcx>, codegen: &mut dyn FnMut(Builder<'a, 'gcc, 'tcx>)) -> (Type<'gcc>, Function<'gcc>) {
+    if let Some(llfn) = cx.rust_try_fn.get() {
+        return llfn;
+    }
+
+    // Define the type up front for the signature of the rust_try function.
+    let tcx = cx.tcx;
+    let i8p = tcx.mk_mut_ptr(tcx.types.i8);
+    // `unsafe fn(*mut i8) -> ()`
+    let try_fn_ty = tcx.mk_fn_ptr(ty::Binder::dummy(tcx.mk_fn_sig(
+        iter::once(i8p),
+        tcx.mk_unit(),
+        false,
+        rustc_hir::Unsafety::Unsafe,
+        Abi::Rust,
+    )));
+    // `unsafe fn(*mut i8, *mut i8) -> ()`
+    let catch_fn_ty = tcx.mk_fn_ptr(ty::Binder::dummy(tcx.mk_fn_sig(
+        [i8p, i8p].iter().cloned(),
+        tcx.mk_unit(),
+        false,
+        rustc_hir::Unsafety::Unsafe,
+        Abi::Rust,
+    )));
+    // `unsafe fn(unsafe fn(*mut i8) -> (), *mut i8, unsafe fn(*mut i8, *mut i8) -> ()) -> i32`
+    let rust_fn_sig = ty::Binder::dummy(cx.tcx.mk_fn_sig(
+        [try_fn_ty, i8p, catch_fn_ty],
+        tcx.types.i32,
+        false,
+        rustc_hir::Unsafety::Unsafe,
+        Abi::Rust,
+    ));
+    let rust_try = gen_fn(cx, "__rust_try", rust_fn_sig, codegen);
+    cx.rust_try_fn.set(Some(rust_try));
+    rust_try
+}
+
+// Helper function to give a Block to a closure to codegen a shim function.
+// This is currently primarily used for the `try` intrinsic functions above.
+#[cfg(feature="master")]
+fn gen_fn<'a, 'gcc, 'tcx>(cx: &'a CodegenCx<'gcc, 'tcx>, name: &str, rust_fn_sig: ty::PolyFnSig<'tcx>, codegen: &mut dyn FnMut(Builder<'a, 'gcc, 'tcx>)) -> (Type<'gcc>, Function<'gcc>) {
+    let fn_abi = cx.fn_abi_of_fn_ptr(rust_fn_sig, ty::List::empty());
+    let (typ, _, _, _) = fn_abi.gcc_type(cx);
+    // FIXME(eddyb) find a nicer way to do this.
+    cx.linkage.set(FunctionType::Internal);
+    let func = cx.declare_fn(name, fn_abi);
+    let func_val = unsafe { std::mem::transmute(func) };
+    cx.set_frame_pointer_type(func_val);
+    cx.apply_target_cpu_attr(func_val);
+    let block = Builder::append_block(cx, func_val, "entry-block");
+    let bx = Builder::build(cx, block);
+    codegen(bx);
+    (typ, func)
+}