From 0f33e9f2816358a4d8afd02af35bd23a4d6d0857 Mon Sep 17 00:00:00 2001 From: "katelyn a. martin" Date: Thu, 10 Sep 2020 13:38:39 -0400 Subject: implement unwinding abi's (RFC 2945) ### Changes This commit implements unwind ABI's, specified in RFC 2945. We adjust the `rustc_middle::ty::layout::fn_can_unwind` function, used to compute whether or not a `FnAbi` object represents a function that should be able to unwind when `panic=unwind` is in use. Changes are also made to `rustc_mir_build::build::should_abort_on_panic` so that the function ABI is used to determind whether it should abort, assuming that the `panic=unwind` strategy is being used, and no explicit unwind attribute was provided. ### Tests Unit tests, checking that the behavior is correct for `C-unwind`, `stdcall-unwind`, `system-unwind`, and `thiscall-unwind`, are included. These alternative `unwind` ABI strings are specified in RFC 2945, in the "_Other `unwind` ABI strings_" section. Additionally, a test case is included to assert that the LLVM IR generated for an external function defined with the `C-unwind` ABI will be appropriately labeled with the `nounwind` LLVM attribute when the `panic=abort` compilation flag is used. ### Ignore Directives This commit uses `ignore-*` directives in two of our `*-unwind` ABI test cases. Specifically, the `stdcall-unwind` and `thiscall-unwind` test cases ignore architectures that do not support `stdcall` and `thiscall`, respectively. These directives are cribbed from `src/test/ui/c-variadic/variadic-ffi-1.rs` for `stdcall`, and `src/test/ui/extern/extern-thiscall.rs` for `thiscall`. --- .../unwind-abis/c-unwind-abi-panic-abort.rs | 18 ++++++++++++ src/test/codegen/unwind-abis/c-unwind-abi.rs | 29 +++++++++++++++++++ src/test/codegen/unwind-abis/stdcall-unwind-abi.rs | 32 +++++++++++++++++++++ src/test/codegen/unwind-abis/system-unwind-abi.rs | 29 +++++++++++++++++++ .../codegen/unwind-abis/thiscall-unwind-abi.rs | 33 ++++++++++++++++++++++ 5 files changed, 141 insertions(+) create mode 100644 src/test/codegen/unwind-abis/c-unwind-abi-panic-abort.rs create mode 100644 src/test/codegen/unwind-abis/c-unwind-abi.rs create mode 100644 src/test/codegen/unwind-abis/stdcall-unwind-abi.rs create mode 100644 src/test/codegen/unwind-abis/system-unwind-abi.rs create mode 100644 src/test/codegen/unwind-abis/thiscall-unwind-abi.rs (limited to 'src/test/codegen') diff --git a/src/test/codegen/unwind-abis/c-unwind-abi-panic-abort.rs b/src/test/codegen/unwind-abis/c-unwind-abi-panic-abort.rs new file mode 100644 index 00000000000..afd65ff6741 --- /dev/null +++ b/src/test/codegen/unwind-abis/c-unwind-abi-panic-abort.rs @@ -0,0 +1,18 @@ +// compile-flags: -C panic=abort -C opt-level=0 + +// Test that `nounwind` atributes are applied to `C-unwind` extern functions when the +// code is compiled with `panic=abort`. We disable optimizations above to prevent LLVM from +// inferring the attribute. + +#![crate_type = "lib"] +#![feature(c_unwind)] + +// CHECK: @rust_item_that_can_unwind() unnamed_addr #0 { +#[no_mangle] +pub extern "C-unwind" fn rust_item_that_can_unwind() { +} + +// Now, make sure that the LLVM attributes for this functions are correct. First, make +// sure that the first item is correctly marked with the `nounwind` attribute: +// +// CHECK: attributes #0 = { {{.*}}nounwind{{.*}} } diff --git a/src/test/codegen/unwind-abis/c-unwind-abi.rs b/src/test/codegen/unwind-abis/c-unwind-abi.rs new file mode 100644 index 00000000000..f1576536753 --- /dev/null +++ b/src/test/codegen/unwind-abis/c-unwind-abi.rs @@ -0,0 +1,29 @@ +// compile-flags: -C opt-level=0 + +// Test that `nounwind` atributes are correctly applied to exported `C` and `C-unwind` extern +// functions. `C-unwind` functions MUST NOT have this attribute. We disable optimizations above +// to prevent LLVM from inferring the attribute. + +#![crate_type = "lib"] +#![feature(c_unwind)] + +// CHECK: @rust_item_that_cannot_unwind() unnamed_addr #0 { +#[no_mangle] +pub extern "C" fn rust_item_that_cannot_unwind() { +} + +// CHECK: @rust_item_that_can_unwind() unnamed_addr #1 { +#[no_mangle] +pub extern "C-unwind" fn rust_item_that_can_unwind() { +} + +// Now, make some assertions that the LLVM attributes for these functions are correct. First, make +// sure that the first item is correctly marked with the `nounwind` attribute: +// +// CHECK: attributes #0 = { {{.*}}nounwind{{.*}} } +// +// Next, let's assert that the second item, which CAN unwind, does not have this attribute. +// +// CHECK: attributes #1 = { +// CHECK-NOT: nounwind +// CHECK: } diff --git a/src/test/codegen/unwind-abis/stdcall-unwind-abi.rs b/src/test/codegen/unwind-abis/stdcall-unwind-abi.rs new file mode 100644 index 00000000000..ed804ca278d --- /dev/null +++ b/src/test/codegen/unwind-abis/stdcall-unwind-abi.rs @@ -0,0 +1,32 @@ +// compile-flags: -C opt-level=0 +// ignore-arm stdcall isn't supported +// ignore-aarch64 stdcall isn't supported +// ignore-riscv64 stdcall isn't supported + +// Test that `nounwind` atributes are correctly applied to exported `stdcall` and `stdcall-unwind` +// extern functions. `stdcall-unwind` functions MUST NOT have this attribute. We disable +// optimizations above to prevent LLVM from inferring the attribute. + +#![crate_type = "lib"] +#![feature(c_unwind)] + +// CHECK: @rust_item_that_cannot_unwind() unnamed_addr #0 { +#[no_mangle] +pub extern "stdcall" fn rust_item_that_cannot_unwind() { +} + +// CHECK: @rust_item_that_can_unwind() unnamed_addr #1 { +#[no_mangle] +pub extern "stdcall-unwind" fn rust_item_that_can_unwind() { +} + +// Now, make some assertions that the LLVM attributes for these functions are correct. First, make +// sure that the first item is correctly marked with the `nounwind` attribute: +// +// CHECK: attributes #0 = { {{.*}}nounwind{{.*}} } +// +// Next, let's assert that the second item, which CAN unwind, does not have this attribute. +// +// CHECK: attributes #1 = { +// CHECK-NOT: nounwind +// CHECK: } diff --git a/src/test/codegen/unwind-abis/system-unwind-abi.rs b/src/test/codegen/unwind-abis/system-unwind-abi.rs new file mode 100644 index 00000000000..c4d51328352 --- /dev/null +++ b/src/test/codegen/unwind-abis/system-unwind-abi.rs @@ -0,0 +1,29 @@ +// compile-flags: -C opt-level=0 + +// Test that `nounwind` atributes are correctly applied to exported `system` and `system-unwind` +// extern functions. `system-unwind` functions MUST NOT have this attribute. We disable +// optimizations above to prevent LLVM from inferring the attribute. + +#![crate_type = "lib"] +#![feature(c_unwind)] + +// CHECK: @rust_item_that_cannot_unwind() unnamed_addr #0 { +#[no_mangle] +pub extern "system" fn rust_item_that_cannot_unwind() { +} + +// CHECK: @rust_item_that_can_unwind() unnamed_addr #1 { +#[no_mangle] +pub extern "system-unwind" fn rust_item_that_can_unwind() { +} + +// Now, make some assertions that the LLVM attributes for these functions are correct. First, make +// sure that the first item is correctly marked with the `nounwind` attribute: +// +// CHECK: attributes #0 = { {{.*}}nounwind{{.*}} } +// +// Next, let's assert that the second item, which CAN unwind, does not have this attribute. +// +// CHECK: attributes #1 = { +// CHECK-NOT: nounwind +// CHECK: } diff --git a/src/test/codegen/unwind-abis/thiscall-unwind-abi.rs b/src/test/codegen/unwind-abis/thiscall-unwind-abi.rs new file mode 100644 index 00000000000..aaa63ae55c3 --- /dev/null +++ b/src/test/codegen/unwind-abis/thiscall-unwind-abi.rs @@ -0,0 +1,33 @@ +// compile-flags: -C opt-level=0 +// ignore-arm thiscall isn't supported +// ignore-aarch64 thiscall isn't supported +// ignore-riscv64 thiscall isn't supported + +// Test that `nounwind` atributes are correctly applied to exported `thiscall` and +// `thiscall-unwind` extern functions. `thiscall-unwind` functions MUST NOT have this attribute. We +// disable optimizations above to prevent LLVM from inferring the attribute. + +#![crate_type = "lib"] +#![feature(abi_thiscall)] +#![feature(c_unwind)] + +// CHECK: @rust_item_that_cannot_unwind() unnamed_addr #0 { +#[no_mangle] +pub extern "thiscall" fn rust_item_that_cannot_unwind() { +} + +// CHECK: @rust_item_that_can_unwind() unnamed_addr #1 { +#[no_mangle] +pub extern "thiscall-unwind" fn rust_item_that_can_unwind() { +} + +// Now, make some assertions that the LLVM attributes for these functions are correct. First, make +// sure that the first item is correctly marked with the `nounwind` attribute: +// +// CHECK: attributes #0 = { {{.*}}nounwind{{.*}} } +// +// Next, let's assert that the second item, which CAN unwind, does not have this attribute. +// +// CHECK: attributes #1 = { +// CHECK-NOT: nounwind +// CHECK: } -- cgit 1.4.1-3-g733a5