From f21a6b7f6b38bb7864785dcd590d864c04b1d8d7 Mon Sep 17 00:00:00 2001 From: Heejin Ahn Date: Fri, 30 Jun 2017 00:43:15 +0000 Subject: [PATCH] [WebAssembly] Add support for exception handling instructions Summary: This adds backend support for throw, rethrow, try, and try_end instructions. This needs the corresponding clang builtin support: https://reviews.llvm.org/D34783 This follows the Wasm exception handling proposal in https://github.com/WebAssembly/exception-handling/blob/master/proposals/Exceptions.md Reviewers: sunfish, dschuff Reviewed By: dschuff Subscribers: jfb, sbc100, jgravelle-google Differential Revision: https://reviews.llvm.org/D34826 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306774 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/IR/IntrinsicsWebAssembly.td | 4 +++ .../WebAssembly/WebAssemblyInstrControl.td | 26 +++++++++++++++---- test/CodeGen/WebAssembly/exception.ll | 22 ++++++++++++++++ 3 files changed, 47 insertions(+), 5 deletions(-) create mode 100644 test/CodeGen/WebAssembly/exception.ll diff --git a/include/llvm/IR/IntrinsicsWebAssembly.td b/include/llvm/IR/IntrinsicsWebAssembly.td index 3a0957dfa39..640ef627bc4 100644 --- a/include/llvm/IR/IntrinsicsWebAssembly.td +++ b/include/llvm/IR/IntrinsicsWebAssembly.td @@ -19,4 +19,8 @@ let TargetPrefix = "wasm" in { // All intrinsics start with "llvm.wasm.". def int_wasm_current_memory : Intrinsic<[llvm_anyint_ty], [], [IntrReadMem]>; def int_wasm_grow_memory : Intrinsic<[llvm_anyint_ty], [LLVMMatchType<0>], []>; +// Exception handling intrinsics +def int_wasm_throw: Intrinsic<[], [llvm_i32_ty, llvm_ptr_ty], [Throws]>; +def int_wasm_rethrow: Intrinsic<[], [], [Throws]>; + } diff --git a/lib/Target/WebAssembly/WebAssemblyInstrControl.td b/lib/Target/WebAssembly/WebAssemblyInstrControl.td index 39cb1ca336f..12979417146 100644 --- a/lib/Target/WebAssembly/WebAssemblyInstrControl.td +++ b/lib/Target/WebAssembly/WebAssemblyInstrControl.td @@ -57,17 +57,19 @@ def BR_TABLE_I64 : I<(outs), (ins I64:$index, variable_ops), } } // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 -// Placemarkers to indicate the start or end of a block or loop scope. These -// use/clobber VALUE_STACK to prevent them from being moved into the middle of -// an expression tree. +// Placemarkers to indicate the start or end of a block, loop, or try scope. +// These use/clobber VALUE_STACK to prevent them from being moved into the +// middle of an expression tree. let Uses = [VALUE_STACK], Defs = [VALUE_STACK] in { def BLOCK : I<(outs), (ins Signature:$sig), [], "block \t$sig", 0x02>; def LOOP : I<(outs), (ins Signature:$sig), [], "loop \t$sig", 0x03>; +def TRY : I<(outs), (ins Signature:$sig), [], "try \t$sig", 0x06>; -// END_BLOCK, END_LOOP, and END_FUNCTION are represented with the same opcode -// in wasm. +// END_BLOCK, END_LOOP, END_TRY, and END_FUNCTION are represented with the same +// opcode in wasm. def END_BLOCK : I<(outs), (ins), [], "end_block", 0x0b>; def END_LOOP : I<(outs), (ins), [], "end_loop", 0x0b>; +def END_TRY : I<(outs), (ins), [], "end_try", 0x0b>; let isTerminator = 1, isBarrier = 1 in def END_FUNCTION : I<(outs), (ins), [], "end_function", 0x0b>; } // Uses = [VALUE_STACK], Defs = [VALUE_STACK] @@ -112,6 +114,20 @@ let isReturn = 1 in { def UNREACHABLE : I<(outs), (ins), [(trap)], "unreachable", 0x00>; +def THROW_I32 : I<(outs), (ins i32imm:$tag, I32:$obj), + [(int_wasm_throw imm:$tag, I32:$obj)], "throw \t$tag, $obj", + 0x08>; +def THROW_I64 : I<(outs), (ins i32imm:$tag, I64:$obj), + [(int_wasm_throw imm:$tag, I64:$obj)], "throw \t$tag, $obj", + 0x08>; +def RETHROW : I<(outs), (ins i32imm:$rel_depth), [], "rethrow \t$rel_depth", + 0x09>; + } // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 } // Defs = [ARGUMENTS] + +// rethrow takes a relative depth as an argument, for which currently only 0 is +// possible for C++. Once other languages need depths other than 0, depths will +// be computed in CFGStackify. +def : Pat<(int_wasm_rethrow), (RETHROW 0)>; diff --git a/test/CodeGen/WebAssembly/exception.ll b/test/CodeGen/WebAssembly/exception.ll new file mode 100644 index 00000000000..eedb5c78b24 --- /dev/null +++ b/test/CodeGen/WebAssembly/exception.ll @@ -0,0 +1,22 @@ +; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals | FileCheck %s + +target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128" +target triple = "wasm32-unknown-unknown-wasm" + +declare void @llvm.wasm.throw(i32, i8*) +declare void @llvm.wasm.rethrow() + +; CHECK-LABEL: throw: +; CHECK-NEXT: i32.const $push0=, 0 +; CHECK-NEXT: throw 0, $pop0 +define void @throw() { + call void @llvm.wasm.throw(i32 0, i8* null) + ret void +} + +; CHECK-LABEL: rethrow: +; CHECK-NEXT: rethrow 0 +define void @rethrow() { + call void @llvm.wasm.rethrow() + ret void +}