Merge pull request #244 from rust-lang/feature/unwinding

Implement unwinding
2024-11-23 15:23:46 +00:00 · 2023-01-11 00:24:47 -05:00 · 2023-01-11 00:24:47 -05:00 · 6c5a70de20
commit 6c5a70de20
parent 7c1d21c3b9 8e77fbf0cc
20 changed files with 388 additions and 97 deletions
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@ -19,9 +19,9 @@ jobs:
      fail-fast: false
      matrix:
        libgccjit_version:
-          - { gcc: "libgccjit.so", extra: "", artifacts_branch: "master" }
-          - { gcc: "libgccjit_without_int128.so", extra: "", artifacts_branch: "master-without-128bit-integers" }
-          - { gcc: "libgccjit12.so", extra: "--no-default-features", artifacts_branch: "gcc12" }
+          - { gcc: "libgccjit.so", extra: "", env_extra: "", artifacts_branch: "master" }
+          - { gcc: "libgccjit_without_int128.so", extra: "", env_extra: "", artifacts_branch: "master-without-128bit-integers" }
+          - { gcc: "libgccjit12.so", extra: "--no-default-features", env_extra: "TEST_FLAGS='-Cpanic=abort -Zpanic-abort-tests'", artifacts_branch: "gcc12" }
        commands: [
          "--mini-tests",
          "--std-tests",
@ -120,8 +120,8 @@ jobs:
    - name: Build
      run: |
        ./prepare_build.sh
-        ./build.sh ${{ matrix.libgccjit_version.extra }}
-        cargo test ${{ matrix.libgccjit_version.extra }}
+        ${{ matrix.libgccjit_version.env_extra }} ./build.sh ${{ matrix.libgccjit_version.extra }}
+        ${{ matrix.libgccjit_version.env_extra }} cargo test ${{ matrix.libgccjit_version.extra }}
        ./clean_all.sh

    - name: Prepare dependencies
@ -143,7 +143,7 @@ jobs:

    - name: Run tests
      run: |
-        ./test.sh --release --clean --build-sysroot ${{ matrix.commands }} ${{ matrix.libgccjit_version.extra }}
+        ${{ matrix.libgccjit_version.env_extra }} ./test.sh --release --clean --build-sysroot ${{ matrix.commands }} ${{ matrix.libgccjit_version.extra }}

  duplicates:
    runs-on: ubuntu-latest
--- a/Cargo.lock
+++ b/Cargo.lock
@ -41,7 +41,7 @@ dependencies = [
 [[package]]
 name = "gccjit"
 version = "1.0.0"
-source = "git+https://github.com/antoyo/gccjit.rs#f30cc2bd330f4fda3d625f305bdfd7e523e2d8f8"
+source = "git+https://github.com/antoyo/gccjit.rs#1e6ecc67fe73ac995e511516eacf4fe3aec8974e"
 dependencies = [
 "gccjit_sys",
 ]
@ -49,7 +49,7 @@ dependencies = [
 [[package]]
 name = "gccjit_sys"
 version = "0.0.1"
-source = "git+https://github.com/antoyo/gccjit.rs#f30cc2bd330f4fda3d625f305bdfd7e523e2d8f8"
+source = "git+https://github.com/antoyo/gccjit.rs#1e6ecc67fe73ac995e511516eacf4fe3aec8974e"
 dependencies = [
 "libc 0.1.12",
 ]
--- a/Readme.md
+++ b/Readme.md
@ -162,8 +162,26 @@ To print a debug representation of a tree:
 debug_tree(expr);
 ```

+(defined in print-tree.h)
+
+To print a debug reprensentation of a gimple struct:
+
+```c
+debug_gimple_stmt(gimple_struct)
+```
+
 To get the `rustc` command to run in `gdb`, add the `--verbose` flag to `cargo build`.

+To have the correct file paths in `gdb` instead of `/usr/src/debug/gcc/libstdc++-v3/libsupc++/eh_personality.cc`, TODO
+
+Maybe by calling the following at the beginning of gdb:
+
+```
+set substitute-path /usr/src/debug/gcc /path/to/gcc-repo/gcc
+```
+
+TODO: but that's not what I remember I was doing.
+
 ### How to use a custom-build rustc

 * Build the stage2 compiler (`rustup toolchain link debug-current build/x86_64-unknown-linux-gnu/stage2`).
--- a/build_sysroot/build_sysroot.sh
+++ b/build_sysroot/build_sysroot.sh
@ -16,7 +16,7 @@ rm Cargo.lock test_target/Cargo.lock 2>/dev/null || true
 rm -r sysroot/ 2>/dev/null || true

 # Build libs
-export RUSTFLAGS="$RUSTFLAGS -Z force-unstable-if-unmarked -Cpanic=abort"
+export RUSTFLAGS="$RUSTFLAGS -Z force-unstable-if-unmarked"
 if [[ "$1" == "--release" ]]; then
    sysroot_channel='release'
    RUSTFLAGS="$RUSTFLAGS -Zmir-opt-level=3" cargo build --target $TARGET_TRIPLE --release
--- a/config.sh
+++ b/config.sh
@ -38,7 +38,7 @@ if [[ "$HOST_TRIPLE" != "$TARGET_TRIPLE" ]]; then
   fi
 fi

-export RUSTFLAGS="$CG_RUSTFLAGS $linker -Cpanic=abort -Csymbol-mangling-version=v0 -Cdebuginfo=2 -Clto=off -Zpanic-abort-tests -Zcodegen-backend=$(pwd)/target/${CHANNEL:-debug}/librustc_codegen_gcc.$dylib_ext --sysroot $(pwd)/build_sysroot/sysroot"
+export RUSTFLAGS="$CG_RUSTFLAGS $linker -Csymbol-mangling-version=v0 -Cdebuginfo=2 -Clto=off -Zcodegen-backend=$(pwd)/target/${CHANNEL:-debug}/librustc_codegen_gcc.$dylib_ext --sysroot $(pwd)/build_sysroot/sysroot $TEST_FLAGS"

 # FIXME(antoyo): remove once the atomic shim is gone
 if [[ `uname` == 'Darwin' ]]; then
--- a/example/alloc_example.rs
+++ b/example/alloc_example.rs
@ -1,4 +1,4 @@
-#![feature(start, box_syntax, core_intrinsics, alloc_error_handler)]
+#![feature(start, box_syntax, core_intrinsics, alloc_error_handler, lang_items)]
 #![no_std]

 extern crate alloc;
@ -26,6 +26,16 @@ fn alloc_error_handler(_: alloc::alloc::Layout) -> ! {
    core::intrinsics::abort();
 }

+#[lang = "eh_personality"]
+fn eh_personality() -> ! {
+    loop {}
+}
+
+#[no_mangle]
+unsafe extern "C" fn _Unwind_Resume() {
+    core::intrinsics::unreachable();
+}
+
 #[start]
 fn main(_argc: isize, _argv: *const *const u8) -> isize {
    let world: Box<&str> = box "Hello World!\0";
--- a/failing-ui-tests.txt
+++ b/failing-ui-tests.txt
@ -41,3 +41,29 @@ src/test/ui/sse2.rs
 src/test/ui/statics/issue-91050-1.rs
 src/test/ui/statics/issue-91050-2.rs
 src/test/ui/target-feature/missing-plusminus.rs
+src/test/ui/asm/x86_64/may_unwind.rs
+src/test/ui/backtrace.rs
+src/test/ui/catch-unwind-bang.rs
+src/test/ui/cfg/cfg-panic-abort.rs
+src/test/ui/drop/dynamic-drop-async.rs
+src/test/ui/drop/repeat-drop.rs
+src/test/ui/fmt/format-args-capture.rs
+src/test/ui/generator/panic-drops-resume.rs
+src/test/ui/generator/panic-drops.rs
+src/test/ui/generator/panic-safe.rs
+src/test/ui/intrinsics/panic-uninitialized-zeroed.rs
+src/test/ui/issues/issue-14875.rs
+src/test/ui/issues/issue-29948.rs
+src/test/ui/issues/issue-43853.rs
+src/test/ui/iterators/iter-sum-overflow-debug.rs
+src/test/ui/iterators/iter-sum-overflow-overflow-checks.rs
+src/test/ui/mir/mir_calls_to_shims.rs
+src/test/ui/mir/mir_drop_order.rs
+src/test/ui/mir/mir_let_chains_drop_order.rs
+src/test/ui/oom_unwind.rs
+src/test/ui/panic-runtime/abort-link-to-unwinding-crates.rs
+src/test/ui/panic-runtime/abort.rs
+src/test/ui/panic-runtime/link-to-abort.rs
+src/test/ui/rfc-2091-track-caller/std-panic-locations.rs
+src/test/ui/rfcs/rfc1857-drop-order.rs
+src/test/ui/unwind-no-uwtable.rs
--- a/failing-ui-tests12.txt
+++ b/failing-ui-tests12.txt
@ -22,3 +22,12 @@ src/test/ui/simd/intrinsic/inlining-issue67557.rs
 src/test/ui/simd/monomorphize-shuffle-index.rs
 src/test/ui/simd/shuffle.rs
 src/test/ui/simd/simd-bitmask.rs
+src/test/ui/binding/fn-arg-incomplete-pattern-drop-order.rs
+src/test/ui/drop/dynamic-drop.rs
+src/test/ui/generator/resume-after-return.rs
+src/test/ui/iterators/iter-step-overflow-debug.rs
+src/test/ui/macros/rfc-2011-nicer-assert-messages/all-expr-kinds.rs
+src/test/ui/numbers-arithmetic/next-power-of-two-overflow-debug.rs
+src/test/ui/panic-while-printing.rs
+src/test/ui/privacy/reachable-unnameable-items.rs
+src/test/ui/rfc-1937-termination-trait/termination-trait-in-test.rs
--- a/src/asm.rs
+++ b/src/asm.rs
@ -352,8 +352,7 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
                    inputs.push(AsmInOperand {
                        constraint: "X".into(),
                        rust_idx,
-                        val: self.cx.rvalue_as_function(get_fn(self.cx, instance))
-                            .get_address(None),
+                        val: get_fn(self.cx, instance).get_address(None),
                    });
                }

@ -739,7 +738,7 @@ impl<'gcc, 'tcx> AsmMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
                        }

                        GlobalAsmOperandRef::SymFn { instance } => {
-                            let function = self.rvalue_as_function(get_fn(self, instance));
+                            let function = get_fn(self, instance);
                            self.add_used_function(function);
                            // TODO(@Amanieu): Additional mangling is needed on
                            // some targets to add a leading underscore (Mach-O)
--- a/src/base.rs
+++ b/src/base.rs
@ -87,6 +87,10 @@ pub fn compile_codegen_unit<'tcx>(tcx: TyCtxt<'tcx>, cgu_name: Symbol, supports_
        // Instantiate monomorphizations without filling out definitions yet...
        //let llvm_module = ModuleLlvm::new(tcx, &cgu_name.as_str());
        let context = Context::default();
+
+        context.add_command_line_option("-fexceptions");
+        context.add_driver_option("-fexceptions");
+
        // TODO(antoyo): only set on x86 platforms.
        context.add_command_line_option("-masm=intel");
        // TODO(antoyo): only add the following cli argument if the feature is supported.
@ -146,7 +150,7 @@ pub fn compile_codegen_unit<'tcx>(tcx: TyCtxt<'tcx>, cgu_name: Symbol, supports_
            context.set_keep_intermediates(true);
        }

-        // TODO(bjorn3): Remove once unwinding is properly implemented
+        // NOTE: The codegen generates unrechable blocks.
        context.set_allow_unreachable_blocks(true);

        {
--- a/src/builder.rs
+++ b/src/builder.rs
@ -372,10 +372,11 @@ impl<'tcx> FnAbiOfHelpers<'tcx> for Builder<'_, '_, 'tcx> {
    }
 }

-impl<'gcc, 'tcx> Deref for Builder<'_, 'gcc, 'tcx> {
+impl<'a, 'gcc, 'tcx> Deref for Builder<'a, 'gcc, 'tcx> {
    type Target = CodegenCx<'gcc, 'tcx>;

-    fn deref(&self) -> &Self::Target {
+    fn deref<'b>(&'b self) -> &'a Self::Target
+    {
        self.cx
    }
 }
@ -393,7 +394,7 @@ impl<'gcc, 'tcx> BackendTypes for Builder<'_, 'gcc, 'tcx> {
 }

 impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
-    fn build(cx: &'a CodegenCx<'gcc, 'tcx>, block: Block<'gcc>) -> Self {
+    fn build(cx: &'a CodegenCx<'gcc, 'tcx>, block: Block<'gcc>) -> Builder<'a, 'gcc, 'tcx> {
        Builder::with_cx(cx, block)
    }

@ -450,8 +451,36 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
        self.block.end_with_switch(None, value, default_block, &gcc_cases);
    }

+    #[cfg(feature="master")]
+    fn invoke(&mut self, typ: Type<'gcc>, func: RValue<'gcc>, args: &[RValue<'gcc>], then: Block<'gcc>, catch: Block<'gcc>, _funclet: Option<&Funclet>) -> RValue<'gcc> {
+        let try_block = self.current_func().new_block("try");
+
+        let current_block = self.block.clone();
+        self.block = try_block;
+        let call = self.call(typ, func, args, None); // TODO(antoyo): use funclet here?
+        self.block = current_block;
+
+        let return_value = self.current_func()
+            .new_local(None, call.get_type(), "invokeResult");
+
+        try_block.add_assignment(None, return_value, call);
+
+        try_block.end_with_jump(None, then);
+
+        if self.cleanup_blocks.borrow().contains(&catch) {
+            self.block.add_try_finally(None, try_block, catch);
+        }
+        else {
+            self.block.add_try_catch(None, try_block, catch);
+        }
+
+        self.block.end_with_jump(None, then);
+
+        return_value.to_rvalue()
+    }
+
+    #[cfg(not(feature="master"))]
    fn invoke(&mut self, typ: Type<'gcc>, func: RValue<'gcc>, args: &[RValue<'gcc>], then: Block<'gcc>, catch: Block<'gcc>, _funclet: Option<&Funclet>) -> RValue<'gcc> {
-        // TODO(bjorn3): Properly implement unwinding.
        let call_site = self.call(typ, func, args, None);
        let condition = self.context.new_rvalue_from_int(self.bool_type, 1);
        self.llbb().end_with_conditional(None, condition, then, catch);
@ -1161,22 +1190,61 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
    }

    fn set_personality_fn(&mut self, _personality: RValue<'gcc>) {
-        // TODO(antoyo)
+        #[cfg(feature="master")]
+        {
+            let personality = self.rvalue_as_function(_personality);
+            self.current_func().set_personality_function(personality);
+        }
    }

+    #[cfg(feature="master")]
+    fn cleanup_landing_pad(&mut self, _ty: Type<'gcc>, pers_fn: RValue<'gcc>) -> RValue<'gcc> {
+        self.set_personality_fn(pers_fn);
+
+        // NOTE: insert the current block in a variable so that a later call to invoke knows to
+        // generate a try/finally instead of a try/catch for this block.
+        self.cleanup_blocks.borrow_mut().insert(self.block);
+
+        let eh_pointer_builtin = self.cx.context.get_target_builtin_function("__builtin_eh_pointer");
+        let zero = self.cx.context.new_rvalue_zero(self.int_type);
+        let ptr = self.cx.context.new_call(None, eh_pointer_builtin, &[zero]);
+
+        let field1_type = self.u8_type.make_pointer();
+        let field1 = self.context.new_field(None, field1_type, "landing_pad_field_1");
+        let field2 = self.context.new_field(None, self.i32_type, "landing_pad_field_2");
+        let struct_type = self.context.new_struct_type(None, "landing_pad", &[field1, field2]);
+        let value = self.current_func().new_local(None, struct_type.as_type(), "landing_pad");
+        let ptr = self.cx.context.new_cast(None, ptr, field1_type);
+        self.block.add_assignment(None, value.access_field(None, field1), ptr);
+        self.block.add_assignment(None, value.access_field(None, field2), zero); // TODO: set the proper value here (the type of exception?).
+
+        value.to_rvalue()
+    }
+
+    #[cfg(not(feature="master"))]
    fn cleanup_landing_pad(&mut self, _ty: Type<'gcc>, _pers_fn: RValue<'gcc>) -> RValue<'gcc> {
        let field1 = self.context.new_field(None, self.u8_type.make_pointer(), "landing_pad_field_1");
        let field2 = self.context.new_field(None, self.i32_type, "landing_pad_field_1");
        let struct_type = self.context.new_struct_type(None, "landing_pad", &[field1, field2]);
        self.current_func().new_local(None, struct_type.as_type(), "landing_pad")
            .to_rvalue()
-        // TODO(antoyo): Properly implement unwinding.
-        // the above is just to make the compilation work as it seems
-        // rustc_codegen_ssa now calls the unwinding builder methods even on panic=abort.
    }

+    #[cfg(feature="master")]
+    fn resume(&mut self, exn: RValue<'gcc>) {
+        // TODO: check if this is normal that we need to dereference the value.
+        // NOTE: the type is wrong, so in order to get a pointer for parameter, cast it to a
+        // pointer of pointer that is later dereferenced.
+        let exn_type = exn.get_type().make_pointer();
+        let exn = self.context.new_cast(None, exn, exn_type);
+        let exn = exn.dereference(None).to_rvalue();
+        let unwind_resume = self.context.get_target_builtin_function("__builtin_unwind_resume");
+        self.llbb().add_eval(None, self.context.new_call(None, unwind_resume, &[exn]));
+        self.unreachable();
+    }
+
+    #[cfg(not(feature="master"))]
    fn resume(&mut self, _exn: RValue<'gcc>) {
-        // TODO(bjorn3): Properly implement unwinding.
        self.unreachable();
    }

--- a/src/callee.rs
+++ b/src/callee.rs
@ -1,11 +1,9 @@
 #[cfg(feature="master")]
 use gccjit::{FnAttribute, Visibility};
-use gccjit::{FunctionType, RValue};
-use rustc_codegen_ssa::traits::BaseTypeMethods;
+use gccjit::{FunctionType, Function};
 use rustc_middle::ty::{self, Instance, TypeVisitable};
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt};

-use crate::abi::FnAbiGccExt;
 use crate::attributes;
 use crate::context::CodegenCx;

@ -16,22 +14,26 @@ use crate::context::CodegenCx;
 ///
 /// - `cx`: the crate context
 /// - `instance`: the instance to be instantiated
-pub fn get_fn<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, instance: Instance<'tcx>) -> RValue<'gcc> {
+pub fn get_fn<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, instance: Instance<'tcx>) -> Function<'gcc> {
    let tcx = cx.tcx();

    assert!(!instance.substs.needs_infer());
    assert!(!instance.substs.has_escaping_bound_vars());

+    let sym = tcx.symbol_name(instance).name;
+
    if let Some(&func) = cx.function_instances.borrow().get(&instance) {
        return func;
    }

-    let sym = tcx.symbol_name(instance).name;
-
    let fn_abi = cx.fn_abi_of_instance(instance, ty::List::empty());

    let func =
-        if let Some(func) = cx.get_declared_value(&sym) {
+        if let Some(_func) = cx.get_declared_value(&sym) {
+            // FIXME: we never reach this because get_declared_value only returns global variables
+            // and here we try to get a function.
+            unreachable!();
+            /*
            // Create a fn pointer with the new signature.
            let ptrty = fn_abi.ptr_to_gcc_type(cx);

@ -64,7 +66,7 @@ pub fn get_fn<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, instance: Instance<'tcx>)
            }
            else {
                func
-            }
+            }*/
        }
        else {
            cx.linkage.set(FunctionType::Extern);
@ -163,8 +165,7 @@ pub fn get_fn<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, instance: Instance<'tcx>)
                }
            }

-            // FIXME(antoyo): this is a wrong cast. That requires changing the compiler API.
-            unsafe { std::mem::transmute(func) }
+            func
        };

    cx.function_instances.borrow_mut().insert(instance, func);
--- a/src/context.rs
+++ b/src/context.rs
@ -4,6 +4,7 @@ use gccjit::{Block, CType, Context, Function, FunctionPtrType, FunctionType, LVa
 use rustc_codegen_ssa::base::wants_msvc_seh;
 use rustc_codegen_ssa::traits::{
    BackendTypes,
+    BaseTypeMethods,
    MiscMethods,
 };
 use rustc_data_structures::base_n;
@ -11,7 +12,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_middle::span_bug;
 use rustc_middle::mir::mono::CodegenUnit;
 use rustc_middle::ty::{self, Instance, ParamEnv, PolyExistentialTraitRef, Ty, TyCtxt};
-use rustc_middle::ty::layout::{FnAbiError, FnAbiOfHelpers, FnAbiRequest, HasParamEnv, HasTyCtxt, LayoutError, TyAndLayout, LayoutOfHelpers};
+use rustc_middle::ty::layout::{FnAbiError, FnAbiOf, FnAbiOfHelpers, FnAbiRequest, HasParamEnv, HasTyCtxt, LayoutError, TyAndLayout, LayoutOfHelpers};
 use rustc_session::Session;
 use rustc_span::Span;
 use rustc_target::abi::{call::FnAbi, HasDataLayout, PointeeInfo, Size, TargetDataLayout, VariantIdx};
@ -82,7 +83,7 @@ pub struct CodegenCx<'gcc, 'tcx> {
    /// Cache instances of monomorphic and polymorphic items
    pub instances: RefCell<FxHashMap<Instance<'tcx>, LValue<'gcc>>>,
    /// Cache function instances of monomorphic and polymorphic items
-    pub function_instances: RefCell<FxHashMap<Instance<'tcx>, RValue<'gcc>>>,
+    pub function_instances: RefCell<FxHashMap<Instance<'tcx>, Function<'gcc>>>,
    /// Cache generated vtables
    pub vtables: RefCell<FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), RValue<'gcc>>>,

@ -109,6 +110,7 @@ pub struct CodegenCx<'gcc, 'tcx> {
    local_gen_sym_counter: Cell<usize>,

    eh_personality: Cell<Option<RValue<'gcc>>>,
+    pub rust_try_fn: Cell<Option<(Type<'gcc>, Function<'gcc>)>>,

    pub pointee_infos: RefCell<FxHashMap<(Ty<'tcx>, Size), Option<PointeeInfo>>>,

@ -118,6 +120,8 @@ pub struct CodegenCx<'gcc, 'tcx> {
    /// they can be dereferenced later.
    /// FIXME(antoyo): fix the rustc API to avoid having this hack.
    pub structs_as_pointer: RefCell<FxHashSet<RValue<'gcc>>>,
+
+    pub cleanup_blocks: RefCell<FxHashSet<Block<'gcc>>>,
 }

 impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
@ -245,15 +249,18 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
            struct_types: Default::default(),
            local_gen_sym_counter: Cell::new(0),
            eh_personality: Cell::new(None),
+            rust_try_fn: Cell::new(None),
            pointee_infos: Default::default(),
            structs_as_pointer: Default::default(),
+            cleanup_blocks: Default::default(),
        }
    }

    pub fn rvalue_as_function(&self, value: RValue<'gcc>) -> Function<'gcc> {
        let function: Function<'gcc> = unsafe { std::mem::transmute(value) };
+        // FIXME: seems like self.functions get overwritten for rust_eh_personality.
        debug_assert!(self.functions.borrow().values().find(|value| **value == function).is_some(),
-            "{:?} ({:?}) is not a function", value, value.get_type());
+            "{:?} is not a function", function);
        function
    }

@ -326,8 +333,8 @@ impl<'gcc, 'tcx> MiscMethods<'tcx> for CodegenCx<'gcc, 'tcx> {

    fn get_fn(&self, instance: Instance<'tcx>) -> RValue<'gcc> {
        let func = get_fn(self, instance);
-        *self.current_func.borrow_mut() = Some(self.rvalue_as_function(func));
-        func
+        *self.current_func.borrow_mut() = Some(func);
+        unsafe { std::mem::transmute(func) }
    }

    fn get_fn_addr(&self, instance: Instance<'tcx>) -> RValue<'gcc> {
@ -338,8 +345,7 @@ impl<'gcc, 'tcx> MiscMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
                self.intrinsics.borrow()[func_name].clone()
            }
            else {
-                let func = get_fn(self, instance);
-                self.rvalue_as_function(func)
+                get_fn(self, instance)
            };
        let ptr = func.get_address(None);

@ -377,31 +383,40 @@ impl<'gcc, 'tcx> MiscMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
            return llpersonality;
        }
        let tcx = self.tcx;
-        let llfn = match tcx.lang_items().eh_personality() {
-            Some(def_id) if !wants_msvc_seh(self.sess()) => self.get_fn_addr(
-                ty::Instance::resolve(
-                    tcx,
-                    ty::ParamEnv::reveal_all(),
-                    def_id,
-                    tcx.intern_substs(&[]),
-                )
-                .unwrap().unwrap(),
-            ),
-            _ => {
-                let _name = if wants_msvc_seh(self.sess()) {
-                    "__CxxFrameHandler3"
-                } else {
-                    "rust_eh_personality"
-                };
-                //let func = self.declare_func(name, self.type_i32(), &[], true);
-                // FIXME(antoyo): this hack should not be needed. That will probably be removed when
-                // unwinding support is added.
-                self.context.new_rvalue_from_int(self.int_type, 0)
-            }
-        };
+        let func =
+            match tcx.lang_items().eh_personality() {
+                Some(def_id) if !wants_msvc_seh(self.sess()) => {
+                    let instance =
+                        ty::Instance::resolve(
+                            tcx,
+                            ty::ParamEnv::reveal_all(),
+                            def_id,
+                            tcx.intern_substs(&[]),
+                        )
+                        .unwrap().unwrap();
+
+                    let symbol_name = tcx.symbol_name(instance).name;
+                    let fn_abi = self.fn_abi_of_instance(instance, ty::List::empty());
+                    self.linkage.set(FunctionType::Extern);
+                    let func = self.declare_fn(symbol_name, &fn_abi);
+                    let func: RValue<'gcc> = unsafe { std::mem::transmute(func) };
+                    func
+                },
+                _ => {
+                    let name =
+                        if wants_msvc_seh(self.sess()) {
+                            "__CxxFrameHandler3"
+                        }
+                        else {
+                            "rust_eh_personality"
+                        };
+                    let func = self.declare_func(name, self.type_i32(), &[], true);
+                    unsafe { std::mem::transmute(func) }
+                }
+            };
        // TODO(antoyo): apply target cpu attributes.
-        self.eh_personality.set(Some(llfn));
-        llfn
+        self.eh_personality.set(Some(func));
+        func
    }

    fn sess(&self) -> &Session {
--- a/src/declare.rs
+++ b/src/declare.rs
@ -38,12 +38,10 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
        global
    }

-    /*pub fn declare_func(&self, name: &str, return_type: Type<'gcc>, params: &[Type<'gcc>], variadic: bool) -> RValue<'gcc> {
-        self.linkage.set(FunctionType::Exported);
-        let func = declare_raw_fn(self, name, () /*llvm::CCallConv*/, return_type, params, variadic);
-        // FIXME(antoyo): this is a wrong cast. That requires changing the compiler API.
-        unsafe { std::mem::transmute(func) }
-    }*/
+    pub fn declare_func(&self, name: &str, return_type: Type<'gcc>, params: &[Type<'gcc>], variadic: bool) -> Function<'gcc> {
+        self.linkage.set(FunctionType::Extern);
+        declare_raw_fn(self, name, () /*llvm::CCallConv*/, return_type, params, variadic)
+    }

    pub fn declare_global(&self, name: &str, ty: Type<'gcc>, global_kind: GlobalKind, is_tls: bool, link_section: Option<Symbol>) -> LValue<'gcc> {
        let global = self.context.new_global(None, global_kind, ty, name);
--- a/src/intrinsic/llvm.rs
+++ b/src/intrinsic/llvm.rs
@ -705,9 +705,9 @@ pub fn intrinsic<'gcc, 'tcx>(name: &str, cx: &CodegenCx<'gcc, 'tcx>) -> Function
        "llvm.x86.aesni.aesenclast.512" => "__builtin_ia32_vaesenclast_v64qi",
        "llvm.x86.aesni.aesdec.512" => "__builtin_ia32_vaesdec_v64qi",
        "llvm.x86.aesni.aesdeclast.512" => "__builtin_ia32_vaesdeclast_v64qi",
-        "llvm.x86.avx512bf16.cvtne2ps2bf16.128" => "__builtin_ia32_cvtne2ps2bf16_v8hi",
-        "llvm.x86.avx512bf16.cvtne2ps2bf16.256" => "__builtin_ia32_cvtne2ps2bf16_v16hi",
-        "llvm.x86.avx512bf16.cvtne2ps2bf16.512" => "__builtin_ia32_cvtne2ps2bf16_v32hi",
+        "llvm.x86.avx512bf16.cvtne2ps2bf16.128" => "__builtin_ia32_cvtne2ps2bf16_v8bf",
+        "llvm.x86.avx512bf16.cvtne2ps2bf16.256" => "__builtin_ia32_cvtne2ps2bf16_v16bf",
+        "llvm.x86.avx512bf16.cvtne2ps2bf16.512" => "__builtin_ia32_cvtne2ps2bf16_v32bf",
        "llvm.x86.avx512bf16.cvtneps2bf16.256" => "__builtin_ia32_cvtneps2bf16_v8sf",
        "llvm.x86.avx512bf16.cvtneps2bf16.512" => "__builtin_ia32_cvtneps2bf16_v16sf",
        "llvm.x86.avx512bf16.dpbf16ps.128" => "__builtin_ia32_dpbf16ps_v4sf",
--- a/src/intrinsic/mod.rs
+++ b/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, span_invalid_monomorphization_erro
 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;
@ -1115,10 +1126,8 @@ 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(), try_func, &[data], None);
        // Return 0 unconditionally from the intrinsic call;
        // we can never unwind.
@ -1129,6 +1138,143 @@ 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>) {
+    //use std::ops::Deref;
+    //let cx: &CodegenCx<'gcc, '_> = bx.deref();
+    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, 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: add a check in the libgccjit API to prevent this.
+        bx.switch_to_block(current_block);
+        bx.invoke(try_func_ty, 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, 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].iter(),
+        &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)
+}
--- a/src/mono_item.rs
+++ b/src/mono_item.rs
@ -59,5 +59,8 @@ impl<'gcc, 'tcx> PreDefineMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
        // TODO(antoyo): call set_link_section() to allow initializing argc/argv.
        // TODO(antoyo): set unique comdat.
        // TODO(antoyo): use inline attribute from there in linkage.set() above.
+
+        self.functions.borrow_mut().insert(symbol_name.to_string(), decl);
+        self.function_instances.borrow_mut().insert(instance, unsafe { std::mem::transmute(decl) });
    }
 }
--- a/test.sh
+++ b/test.sh
@ -191,11 +191,11 @@ function std_tests() {
    $RUN_WRAPPER ./target/out/std_example --target $TARGET_TRIPLE

    echo "[AOT] subslice-patterns-const-eval"
-    $RUSTC example/subslice-patterns-const-eval.rs --crate-type bin -Cpanic=abort --target $TARGET_TRIPLE
+    $RUSTC example/subslice-patterns-const-eval.rs --crate-type bin $TEST_FLAGS --target $TARGET_TRIPLE
    $RUN_WRAPPER ./target/out/subslice-patterns-const-eval

    echo "[AOT] track-caller-attribute"
-    $RUSTC example/track-caller-attribute.rs --crate-type bin -Cpanic=abort --target $TARGET_TRIPLE
+    $RUSTC example/track-caller-attribute.rs --crate-type bin $TEST_FLAGS --target $TARGET_TRIPLE
    $RUN_WRAPPER ./target/out/track-caller-attribute

    echo "[BUILD] mod_bench"
@ -338,9 +338,9 @@ function test_rustc() {

    git checkout -- src/test/ui/issues/auxiliary/issue-3136-a.rs # contains //~ERROR, but shouldn't be removed

-    rm -r src/test/ui/{abi*,extern/,panic-runtime/,panics/,unsized-locals/,proc-macro/,threads-sendsync/,thinlto/,borrowck/,chalkify/bugs/,test*,*lto*.rs,consts/const-float-bits-reject-conv.rs,consts/issue-miri-1910.rs} || true
+    rm -r src/test/ui/{abi*,extern/,unsized-locals/,proc-macro/,threads-sendsync/,thinlto/,borrowck/,chalkify/bugs/,test*,*lto*.rs,consts/const-float-bits-reject-conv.rs,consts/issue-miri-1910.rs} || true
    rm src/test/ui/mir/mir_heavy_promoted.rs # this tests is oom-killed in the CI.
-    for test in $(rg --files-with-matches "catch_unwind|should_panic|thread|lto" src/test/ui); do
+    for test in $(rg --files-with-matches "thread|lto" src/test/ui); do
      rm $test
    done
    git checkout src/test/ui/lto/auxiliary/dylib.rs
@ -348,7 +348,7 @@ function test_rustc() {
    git checkout src/test/ui/type-alias-impl-trait/auxiliary/cross_crate_ice2.rs
    git checkout src/test/ui/macros/rfc-2011-nicer-assert-messages/auxiliary/common.rs

-    RUSTC_ARGS="-Zpanic-abort-tests -Csymbol-mangling-version=v0 -Zcodegen-backend="$(pwd)"/../target/"$CHANNEL"/librustc_codegen_gcc."$dylib_ext" --sysroot "$(pwd)"/../build_sysroot/sysroot -Cpanic=abort"
+    RUSTC_ARGS="$TEST_FLAGS -Csymbol-mangling-version=v0 -Zcodegen-backend="$(pwd)"/../target/"$CHANNEL"/librustc_codegen_gcc."$dylib_ext" --sysroot "$(pwd)"/../build_sysroot/sysroot"

    if [ $# -eq 0 ]; then
        # No argument supplied to the function. Doing nothing.
--- a/tests/lang_tests_common.rs
+++ b/tests/lang_tests_common.rs
@ -46,11 +46,15 @@ pub fn main_inner(profile: Profile) {
                &format!("-Zcodegen-backend={}/target/debug/librustc_codegen_gcc.so", current_dir),
                "--sysroot", &format!("{}/build_sysroot/sysroot/", current_dir),
                "-Zno-parallel-llvm",
-                "-C", "panic=abort",
                "-C", "link-arg=-lc",
                "-o", exe.to_str().expect("to_str"),
                path.to_str().expect("to_str"),
            ]);
+            if let Some(flags) = option_env!("TEST_FLAGS") {
+                for flag in flags.split_whitespace() {
+                    compiler.arg(&flag);
+                }
+            }
            match profile {
                Profile::Debug => {}
                Profile::Release => {
--- a/tests/run/int.rs
+++ b/tests/run/int.rs
@ -3,22 +3,14 @@
 // Run-time:
 //   status: 0

-#![feature(bench_black_box, const_black_box, core_intrinsics, start)]
-
-#![no_std]
-
-#[panic_handler]
-fn panic_handler(_: &core::panic::PanicInfo) -> ! {
-    core::intrinsics::abort();
-}
+#![feature(bench_black_box, const_black_box)]

 /*
 * Code
 */

-#[start]
-fn main(_argc: isize, _argv: *const *const u8) -> isize {
-    use core::hint::black_box;
+fn main() {
+    use std::hint::black_box;

    macro_rules! check {
        ($ty:ty, $expr:expr) => {
@ -335,6 +327,4 @@ fn main(_argc: isize, _argv: *const *const u8) -> isize {
        const VAL5: T = 73236519889708027473620326106273939584_i128;
        check_ops128!();
    }
-
-    0
 }