aheejin updated this revision to Diff 328116.
aheejin added a comment.
Address comments
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D97834/new/
https://reviews.llvm.org/D97834
Files:
clang/lib/CodeGen/CGException.cpp
clang/lib/CodeGen/ItaniumCXXABI.cpp
clang/test/CodeGenCXX/wasm-eh.cpp
llvm/lib/CodeGen/WasmEHPrepare.cpp
llvm/lib/Target/WebAssembly/CMakeLists.txt
llvm/lib/Target/WebAssembly/WebAssembly.h
llvm/lib/Target/WebAssembly/WebAssemblyHandleEHTerminatePads.cpp
llvm/lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp
llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
llvm/lib/Target/WebAssembly/WebAssemblyUtilities.cpp
llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.ll
llvm/test/CodeGen/WebAssembly/eh-lsda.ll
llvm/test/CodeGen/WebAssembly/exception.ll
llvm/test/CodeGen/WebAssembly/wasmehprepare.ll
Index: llvm/test/CodeGen/WebAssembly/wasmehprepare.ll
===================================================================
--- llvm/test/CodeGen/WebAssembly/wasmehprepare.ll
+++ llvm/test/CodeGen/WebAssembly/wasmehprepare.ll
@@ -132,59 +132,6 @@
ret void
}
-; A cleanuppad with a call to __clang_call_terminate().
-;
-; void foo();
-; void test2() {
-; try {
-; foo();
-; } catch (...) {
-; foo();
-; }
-; }
-define void @test2() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
-; CHECK-LABEL: @test2
-entry:
- invoke void @foo()
- to label %try.cont unwind label %catch.dispatch
-
-catch.dispatch: ; preds = %entry
- %0 = catchswitch within none [label %catch.start] unwind to caller
-
-catch.start: ; preds = %catch.dispatch
- %1 = catchpad within %0 [i8* null]
- %2 = call i8* @llvm.wasm.get.exception(token %1)
- %3 = call i32 @llvm.wasm.get.ehselector(token %1)
- %4 = call i8* @__cxa_begin_catch(i8* %2) [ "funclet"(token %1) ]
- invoke void @foo() [ "funclet"(token %1) ]
- to label %invoke.cont1 unwind label %ehcleanup
-
-invoke.cont1: ; preds = %catch.start
- call void @__cxa_end_catch() [ "funclet"(token %1) ]
- catchret from %1 to label %try.cont
-
-try.cont: ; preds = %entry, %invoke.cont1
- ret void
-
-ehcleanup: ; preds = %catch.start
- %5 = cleanuppad within %1 []
- invoke void @__cxa_end_catch() [ "funclet"(token %5) ]
- to label %invoke.cont2 unwind label %terminate
-
-invoke.cont2: ; preds = %ehcleanup
- cleanupret from %5 unwind to caller
-
-terminate: ; preds = %ehcleanup
- %6 = cleanuppad within %5 []
- %7 = call i8* @llvm.wasm.get.exception(token %6)
- call void @__clang_call_terminate(i8* %7) [ "funclet"(token %6) ]
- unreachable
-; CHECK: terminate:
-; CHECK-NEXT: cleanuppad
-; CHECK-NEXT: %[[EXN:.*]] = call i8* @llvm.wasm.catch
-; CHECK-NEXT: call void @__clang_call_terminate(i8* %[[EXN]])
-}
-
; PHI demotion test. Only the phi before catchswitch should be demoted; the phi
; before cleanuppad should NOT.
;
@@ -194,7 +141,7 @@
; ~Temp() {}
; };
;
-; void test3() {
+; void test2() {
; int num;
; try {
; Temp t;
@@ -214,8 +161,8 @@
; bar(num);
; }
; }
-define void @test3() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
-; CHECK-LABEL: @test3
+define void @test2() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
+; CHECK-LABEL: @test2
entry:
%t = alloca %struct.Temp, align 1
invoke void @foo()
@@ -279,8 +226,8 @@
; Tests if instructions after a call to @llvm.wasm.throw are deleted and the
; BB's dead children are deleted.
-; CHECK-LABEL: @test4
-define i32 @test4(i1 %b, i8* %p) {
+; CHECK-LABEL: @test3
+define i32 @test3(i1 %b, i8* %p) {
entry:
br i1 %b, label %bb.true, label %bb.false
@@ -308,14 +255,22 @@
declare void @bar(i32)
declare %struct.Temp* @_ZN4TempD2Ev(%struct.Temp* returned)
declare i32 @__gxx_wasm_personality_v0(...)
-declare i8* @llvm.wasm.get.exception(token)
-declare i32 @llvm.wasm.get.ehselector(token)
-declare i32 @llvm.eh.typeid.for(i8*)
-declare void @llvm.wasm.throw(i32, i8*)
-declare void @llvm.wasm.rethrow()
+; Function Attrs: nounwind
+declare i8* @llvm.wasm.get.exception(token) #0
+; Function Attrs: nounwind
+declare i32 @llvm.wasm.get.ehselector(token) #0
+; Function Attrs: nounwind
+declare i32 @llvm.eh.typeid.for(i8*) #0
+; Function Attrs: noreturn
+declare void @llvm.wasm.throw(i32, i8*) #1
+; Function Attrs: noreturn
+declare void @llvm.wasm.rethrow() #1
declare i8* @__cxa_begin_catch(i8*)
declare void @__cxa_end_catch()
-declare void @__clang_call_terminate(i8*)
+declare void @_ZSt9terminatev()
+
+attributes #0 = { nounwind }
+attributes #1 = { noreturn }
; CHECK-DAG: declare void @llvm.wasm.landingpad.index(token, i32 immarg)
; CHECK-DAG: declare i8* @llvm.wasm.lsda()
Index: llvm/test/CodeGen/WebAssembly/exception.ll
===================================================================
--- llvm/test/CodeGen/WebAssembly/exception.ll
+++ llvm/test/CodeGen/WebAssembly/exception.ll
@@ -1,5 +1,5 @@
; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -exception-model=wasm -mattr=+exception-handling -verify-machineinstrs | FileCheck --implicit-check-not=ehgcr -allow-deprecated-dag-overlap %s
-; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -exception-model=wasm -mattr=+exception-handling -verify-machineinstrs -O0 | FileCheck -allow-deprecated-dag-overlap --check-prefix=NOOPT %s
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -exception-model=wasm -mattr=+exception-handling -verify-machineinstrs -O0
; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-keep-registers -exception-model=wasm -mattr=+exception-handling
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
@@ -129,9 +129,6 @@
; CHECK: catch_all
; CHECK: try
; CHECK: call __cxa_end_catch
-; CHECK: catch $[[EXN:[0-9]+]]=, __cpp_exception
-; CHECK: call __clang_call_terminate, $[[EXN]]
-; CHECK: unreachable
; CHECK: catch_all
; CHECK: call _ZSt9terminatev
; CHECK: unreachable
@@ -173,75 +170,7 @@
terminate: ; preds = %ehcleanup
%6 = cleanuppad within %5 []
- %7 = call i8* @llvm.wasm.get.exception(token %6)
- call void @__clang_call_terminate(i8* %7) [ "funclet"(token %6) ]
- unreachable
-}
-
-; Tests a case when there are multiple BBs within a terminate pad. This kind of
-; structure is not generated by clang, but can generated by code
-; transformations. After LateEHPrepare, there should be a single 'terminate' BB
-; with these instructions:
-
-; %exn = catch $__cpp_exception
-; call @__clang_call_terminate(%exn)
-; unreachable
-
-; NOOPT-LABEL: test_split_terminatepad
-define void @test_split_terminatepad(i1 %arg) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
-entry:
- invoke void @foo()
- to label %try.cont unwind label %catch.dispatch
-
-catch.dispatch: ; preds = %entry
- %0 = catchswitch within none [label %catch.start] unwind to caller
-
-; NOOPT: catch
-catch.start: ; preds = %catch.dispatch
- %1 = catchpad within %0 [i8* null]
- %2 = call i8* @llvm.wasm.get.exception(token %1)
- %3 = call i32 @llvm.wasm.get.ehselector(token %1)
- %4 = call i8* @__cxa_begin_catch(i8* %2) [ "funclet"(token %1) ]
- invoke void @foo() [ "funclet"(token %1) ]
- to label %invoke.cont1 unwind label %ehcleanup
-
-invoke.cont1: ; preds = %catch.start
- call void @__cxa_end_catch() [ "funclet"(token %1) ]
- catchret from %1 to label %try.cont
-
-try.cont: ; preds = %invoke.cont1, %entry
- ret void
-
-; NOOPT: catch_all
-ehcleanup: ; preds = %catch.start
- %5 = cleanuppad within %1 []
- invoke void @__cxa_end_catch() [ "funclet"(token %5) ]
- to label %invoke.cont2 unwind label %terminate
-
-invoke.cont2: ; preds = %ehcleanup
- cleanupret from %5 unwind to caller
-
-; This weird structure of split terminate pads are not generated by clang, but
-; we cannot guarantee this kind of multi-BB terminate pads cannot be generated
-; by code transformations. This structure is manually created for this test.
-; NOOPT: catch $[[EXN:[0-9]+]]=, __cpp_exception
-; NOOPT-NEXT: global.set __stack_pointer
-; NOOPT-NEXT: call __clang_call_terminate, $[[EXN]]
-; NOOPT-NEXT: unreachable
-
-terminate: ; preds = %ehcleanup
- %6 = cleanuppad within %5 []
- %7 = call i8* @llvm.wasm.get.exception(token %6)
- br i1 %arg, label %terminate.split1, label %terminate.split2
-
-terminate.split1:
- call void @__clang_call_terminate(i8* %7) [ "funclet"(token %6) ]
- unreachable
-
-terminate.split2:
- ; This is to test a hypothetical case that a call to __clang_call_terminate is
- ; duplicated within a terminate pad
- call void @__clang_call_terminate(i8* %7) [ "funclet"(token %6) ]
+ call void @_ZSt9terminatev() [ "funclet"(token %6) ]
unreachable
}
@@ -424,16 +353,23 @@
declare void @foo()
declare void @bar(i32*)
declare i32 @__gxx_wasm_personality_v0(...)
-declare void @llvm.wasm.throw(i32, i8*)
-declare i8* @llvm.wasm.get.exception(token)
-declare i32 @llvm.wasm.get.ehselector(token)
-declare void @llvm.wasm.rethrow()
-declare i32 @llvm.eh.typeid.for(i8*)
+; Function Attrs: noreturn
+declare void @llvm.wasm.throw(i32, i8*) #1
+; Function Attrs: nounwind
+declare i8* @llvm.wasm.get.exception(token) #0
+; Function Attrs: nounwind
+declare i32 @llvm.wasm.get.ehselector(token) #0
+; Function Attrs: noreturn
+declare void @llvm.wasm.rethrow() #1
+; Function Attrs: nounwind
+declare i32 @llvm.eh.typeid.for(i8*) #0
declare i8* @__cxa_begin_catch(i8*)
declare void @__cxa_end_catch()
-declare void @__clang_call_terminate(i8*)
declare void @_ZSt9terminatev()
declare %struct.Temp* @_ZN4TempD2Ev(%struct.Temp* returned)
+attributes #0 = { nounwind }
+attributes #1 = { noreturn }
+
; CHECK: __cpp_exception:
; CHECK: .eventtype __cpp_exception i32
Index: llvm/test/CodeGen/WebAssembly/eh-lsda.ll
===================================================================
--- llvm/test/CodeGen/WebAssembly/eh-lsda.ll
+++ llvm/test/CodeGen/WebAssembly/eh-lsda.ll
@@ -231,10 +231,15 @@
}
declare void @may_throw()
-declare i32 @llvm.eh.typeid.for(i8*)
-declare i8* @llvm.wasm.get.exception(token)
-declare i32 @llvm.wasm.get.ehselector(token)
+; Function Attrs: nounwind
+declare i32 @llvm.eh.typeid.for(i8*) #0
+; Function Attrs: nounwind
+declare i8* @llvm.wasm.get.exception(token) #0
+; Function Attrs: nounwind
+declare i32 @llvm.wasm.get.ehselector(token) #0
declare void @__cxa_rethrow()
declare i8* @__cxa_begin_catch(i8*)
declare void @__cxa_end_catch()
declare i32 @__gxx_wasm_personality_v0(...)
+
+attributes #0 = { nounwind }
Index: llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.ll
===================================================================
--- llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.ll
+++ llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.ll
@@ -233,8 +233,8 @@
; CHECK: catch
; CHECK: try
; CHECK: call __cxa_end_catch
-; CHECK: catch
-; CHECK: call __clang_call_terminate
+; CHECK: catch_all
+; CHECK: call _ZSt9terminatev
; CHECK: unreachable
; CHECK: end_try
; CHECK: rethrow 0 # to caller
@@ -291,8 +291,7 @@
terminate: ; preds = %ehcleanup
%6 = cleanuppad within %5 []
- %7 = call i8* @llvm.wasm.get.exception(token %6)
- call void @__clang_call_terminate(i8* %7) [ "funclet"(token %6) ]
+ call void @_ZSt9terminatev() [ "funclet"(token %6) ]
unreachable
}
@@ -806,8 +805,7 @@
terminate: ; preds = %entry
%0 = cleanuppad within none []
- %1 = tail call i8* @llvm.wasm.get.exception(token %0)
- call void @__clang_call_terminate(i8* %1) [ "funclet"(token %0) ]
+ call void @_ZSt9terminatev() [ "funclet"(token %0) ]
unreachable
}
@@ -876,8 +874,7 @@
terminate7: ; preds = %ehcleanup
%10 = cleanuppad within %9 []
- %11 = call i8* @llvm.wasm.get.exception(token %10)
- call void @__clang_call_terminate(i8* %11) [ "funclet"(token %10) ]
+ call void @_ZSt9terminatev() [ "funclet"(token %10) ]
unreachable
}
@@ -1046,8 +1043,7 @@
ehcleanup: ; preds = %catch.start
%5 = cleanuppad within %1 []
- %6 = call i8* @llvm.wasm.get.exception(token %5)
- call void @__clang_call_terminate(i8* %6) [ "funclet"(token %5) ]
+ call void @_ZSt9terminatev() [ "funclet"(token %5) ]
unreachable
while.end: ; preds = %while.body, %while.cond
@@ -1570,8 +1566,7 @@
; Function Attrs: nounwind
declare i32 @llvm.wasm.get.ehselector(token) #0
declare i8* @__cxa_allocate_exception(i32) #0
-; Function Attrs: noreturn
-declare void @__cxa_throw(i8*, i8*, i8*) #1
+declare void @__cxa_throw(i8*, i8*, i8*)
; Function Attrs: noreturn
declare void @llvm.wasm.rethrow() #1
; Function Attrs: nounwind
@@ -1580,7 +1575,6 @@
declare i8* @__cxa_begin_catch(i8*)
declare void @__cxa_end_catch()
declare i8* @__cxa_get_exception_ptr(i8*)
-declare void @__clang_call_terminate(i8*)
declare void @_ZSt9terminatev()
; Function Attrs: nounwind
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i32, i1 immarg) #0
Index: llvm/lib/Target/WebAssembly/WebAssemblyUtilities.cpp
===================================================================
--- llvm/lib/Target/WebAssembly/WebAssemblyUtilities.cpp
+++ llvm/lib/Target/WebAssembly/WebAssemblyUtilities.cpp
@@ -18,7 +18,6 @@
#include "llvm/MC/MCContext.h"
using namespace llvm;
-const char *const WebAssembly::ClangCallTerminateFn = "__clang_call_terminate";
const char *const WebAssembly::CxaBeginCatchFn = "__cxa_begin_catch";
const char *const WebAssembly::CxaRethrowFn = "__cxa_rethrow";
const char *const WebAssembly::StdTerminateFn = "_ZSt9terminatev";
@@ -73,7 +72,7 @@
return false;
// These functions never throw
if (F->getName() == CxaBeginCatchFn || F->getName() == PersonalityWrapperFn ||
- F->getName() == ClangCallTerminateFn || F->getName() == StdTerminateFn)
+ F->getName() == StdTerminateFn)
return false;
// TODO Can we exclude call instructions that are marked as 'nounwind' in the
Index: llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
===================================================================
--- llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
+++ llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
@@ -82,7 +82,6 @@
initializeWebAssemblyExceptionInfoPass(PR);
initializeWebAssemblyCFGSortPass(PR);
initializeWebAssemblyCFGStackifyPass(PR);
- initializeWebAssemblyHandleEHTerminatePadsPass(PR);
initializeWebAssemblyExplicitLocalsPass(PR);
initializeWebAssemblyLowerBrUnlessPass(PR);
initializeWebAssemblyRegNumberingPass(PR);
@@ -486,10 +485,6 @@
// Insert BLOCK and LOOP markers.
addPass(createWebAssemblyCFGStackify());
- // Handle terminate pads for cleanups
- if (TM->Options.ExceptionModel == ExceptionHandling::Wasm)
- addPass(createWebAssemblyHandleEHTerminatePads());
-
// Insert explicit local.get and local.set operators.
if (!WasmDisableExplicitLocals)
addPass(createWebAssemblyExplicitLocals());
Index: llvm/lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp
===================================================================
--- llvm/lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp
+++ llvm/lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp
@@ -38,7 +38,6 @@
bool addCatchAlls(MachineFunction &MF);
bool replaceFuncletReturns(MachineFunction &MF);
bool removeUnnecessaryUnreachables(MachineFunction &MF);
- bool ensureSingleBBTermPads(MachineFunction &MF);
bool restoreStackPointer(MachineFunction &MF);
MachineBasicBlock *getMatchingEHPad(MachineInstr *MI);
@@ -128,7 +127,6 @@
Changed |= hoistCatches(MF);
Changed |= addCatchAlls(MF);
Changed |= replaceFuncletReturns(MF);
- Changed |= ensureSingleBBTermPads(MF);
}
Changed |= removeUnnecessaryUnreachables(MF);
if (MF.getFunction().hasPersonalityFn())
@@ -288,80 +286,6 @@
return Changed;
}
-// Clang-generated terminate pads are an single-BB EH pad in the form of
-// termpad:
-// %exn = catch $__cpp_exception
-// call @__clang_call_terminate(%exn)
-// unreachable
-// (There can be local.set and local.gets before the call if we didn't run
-// RegStackify)
-// But code transformations can change or add more control flow, so the call to
-// __clang_call_terminate() function may not be in the original EH pad anymore.
-// This ensures every terminate pad is a single BB in the form illustrated
-// above.
-//
-// This is preparation work for the HandleEHTerminatePads pass later, which
-// duplicates terminate pads both for 'catch' and 'catch_all'. Refer to
-// WebAssemblyHandleEHTerminatePads.cpp for details.
-bool WebAssemblyLateEHPrepare::ensureSingleBBTermPads(MachineFunction &MF) {
- const auto &TII = *MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
-
- // Find calls to __clang_call_terminate()
- SmallVector<MachineInstr *, 8> ClangCallTerminateCalls;
- SmallPtrSet<MachineBasicBlock *, 8> TermPads;
- for (auto &MBB : MF) {
- for (auto &MI : MBB) {
- if (MI.isCall()) {
- const MachineOperand &CalleeOp = MI.getOperand(0);
- if (CalleeOp.isGlobal() && CalleeOp.getGlobal()->getName() ==
- WebAssembly::ClangCallTerminateFn) {
- MachineBasicBlock *EHPad = getMatchingEHPad(&MI);
- assert(EHPad && "No matching EH pad for __clang_call_terminate");
- // In case a __clang_call_terminate call is duplicated during code
- // transformation so one terminate pad contains multiple
- // __clang_call_terminate calls, we only count one of them
- if (TermPads.insert(EHPad).second)
- ClangCallTerminateCalls.push_back(&MI);
- }
- }
- }
- }
-
- bool Changed = false;
- for (auto *Call : ClangCallTerminateCalls) {
- MachineBasicBlock *EHPad = getMatchingEHPad(Call);
- assert(EHPad && "No matching EH pad for __clang_call_terminate");
-
- // If it is already the form we want, skip it
- if (Call->getParent() == EHPad &&
- Call->getNextNode()->getOpcode() == WebAssembly::UNREACHABLE)
- continue;
-
- // In case the __clang_call_terminate() call is not in its matching EH pad,
- // move the call to the end of EH pad and add an unreachable instruction
- // after that. Delete all successors and their children if any, because here
- // the program terminates.
- Changed = true;
- // This runs after hoistCatches(), so catch instruction should be at the top
- MachineInstr *Catch = WebAssembly::findCatch(EHPad);
- assert(Catch && "EH pad does not have a catch instruction");
- // Takes the result register of the catch instruction as argument. There may
- // have been some other local.set/local.gets in between, but at this point
- // we don't care.
- Call->getOperand(1).setReg(Catch->getOperand(0).getReg());
- auto InsertPos = std::next(MachineBasicBlock::iterator(Catch));
- EHPad->insert(InsertPos, Call->removeFromParent());
- BuildMI(*EHPad, InsertPos, Call->getDebugLoc(),
- TII.get(WebAssembly::UNREACHABLE));
- EHPad->erase(InsertPos, EHPad->end());
- SmallVector<MachineBasicBlock *, 8> Succs(EHPad->successors());
- for (auto *Succ : Succs)
- EHPad->removeSuccessor(Succ);
- eraseDeadBBsAndChildren(Succs);
- }
- return Changed;
-}
-
// After the stack is unwound due to a thrown exception, the __stack_pointer
// global can point to an invalid address. This inserts instructions that
// restore __stack_pointer global.
Index: llvm/lib/Target/WebAssembly/WebAssemblyHandleEHTerminatePads.cpp
===================================================================
--- llvm/lib/Target/WebAssembly/WebAssemblyHandleEHTerminatePads.cpp
+++ /dev/null
@@ -1,152 +0,0 @@
-// WebAssemblyHandleEHTerminatePads.cpp - WebAssembly Handle EH TerminatePads //
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-///
-/// \file
-/// \brief Add catch_all blocks to terminate pads.
-///
-/// Terminate pads are cleanup pads with a __clang_call_terminate call. These
-/// are reached when an exception is thrown again in the middle of processing a
-/// thrown exception, to terminate the program. These are cleanup pads that
-/// should run regardless whether the thrown exception is a C++ exception or
-/// not.
-///
-/// Because __clang_call_terminate takes an exception pointer, and
-/// llvm.get.exception intrinsic is selected to 'catch' instruction in
-/// instruction selection, terminate pads have a catch instruction and are in
-/// this form after LateEHPrepare, even though they are cleanup pads:
-/// termpad:
-/// %exn = catch $__cpp_exception
-/// call @__clang_call_terminate(%exn)
-/// unreachable
-///
-/// This pass assumes LateEHPrepare ensured every terminate pad is a single
-/// BB.
-///
-/// __clang_call_terminate is a function generated by clang, in the form of
-/// void __clang_call_terminate(i8* %arg) {
-/// call @__cxa_begin_catch(%arg)
-/// call void @std::terminate()
-/// unreachable
-/// }
-///
-/// To make the terminate pads reachable when a foreign exception is thrown,
-/// this pass attaches an additional catch_all BB after this catch terminate pad
-/// BB, with a call to std::terminate, because foreign exceptions don't have a
-/// valid exception pointer to call __cxa_begin_catch with. So the code example
-/// becomes:
-/// termpad:
-/// %exn = catch $__cpp_exception
-/// call @__clang_call_terminate(%exn)
-/// unreachable
-/// termpad-catchall:
-/// catch_all
-/// call @std::terminate()
-/// unreachable
-///
-/// We do this at the very end of compilation pipeline, even after CFGStackify,
-/// because even though wasm spec allows multiple catch/catch_all blocks per a
-/// try instruction, it has been convenient to maintain the invariant so far
-/// that there has been only a single catch or catch_all attached to a try. This
-/// assumption makes ExceptionInfo generation and CFGStackify simpler, because
-/// we have been always able to assume an EH pad is an end of try block and a
-/// start of catch/catch_all block.
-//===----------------------------------------------------------------------===//
-
-#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
-#include "WebAssembly.h"
-#include "WebAssemblySubtarget.h"
-#include "WebAssemblyUtilities.h"
-#include "llvm/CodeGen/MachineModuleInfo.h"
-#include "llvm/MC/MCAsmInfo.h"
-#include "llvm/Target/TargetMachine.h"
-using namespace llvm;
-
-#define DEBUG_TYPE "wasm-handle-termpads"
-
-namespace {
-class WebAssemblyHandleEHTerminatePads final : public MachineFunctionPass {
- StringRef getPassName() const override {
- return "WebAssembly Handle EH Terminate Pads";
- }
-
- bool runOnMachineFunction(MachineFunction &MF) override;
-
-public:
- static char ID; // Pass identification, replacement for typeid
- WebAssemblyHandleEHTerminatePads() : MachineFunctionPass(ID) {}
-};
-} // end anonymous namespace
-
-char WebAssemblyHandleEHTerminatePads::ID = 0;
-INITIALIZE_PASS(WebAssemblyHandleEHTerminatePads, DEBUG_TYPE,
- "WebAssembly Handle EH Terminate Pads", false, false)
-
-FunctionPass *llvm::createWebAssemblyHandleEHTerminatePads() {
- return new WebAssemblyHandleEHTerminatePads();
-}
-
-bool WebAssemblyHandleEHTerminatePads::runOnMachineFunction(
- MachineFunction &MF) {
- LLVM_DEBUG(dbgs() << "********** Handle EH Terminate Pads **********\n"
- "********** Function: "
- << MF.getName() << '\n');
-
- if (MF.getTarget().getMCAsmInfo()->getExceptionHandlingType() !=
- ExceptionHandling::Wasm ||
- !MF.getFunction().hasPersonalityFn())
- return false;
-
- const auto &TII = *MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
-
- // Find calls to __clang_call_terminate()
- SmallVector<MachineInstr *, 8> ClangCallTerminateCalls;
- for (auto &MBB : MF) {
- for (auto &MI : MBB) {
- if (MI.isCall()) {
- const MachineOperand &CalleeOp = MI.getOperand(0);
- if (CalleeOp.isGlobal() && CalleeOp.getGlobal()->getName() ==
- WebAssembly::ClangCallTerminateFn)
- ClangCallTerminateCalls.push_back(&MI);
- }
- }
- }
-
- if (ClangCallTerminateCalls.empty())
- return false;
-
- for (auto *Call : ClangCallTerminateCalls) {
- // This should be an EH pad because LateEHPrepare ensures terminate pads are
- // a single BB.
- MachineBasicBlock *CatchBB = Call->getParent();
- assert(CatchBB->isEHPad());
-
- auto *CatchAllBB = MF.CreateMachineBasicBlock();
- MF.insert(std::next(CatchBB->getIterator()), CatchAllBB);
- CatchAllBB->setIsEHPad(true);
- for (auto *Pred : CatchBB->predecessors())
- Pred->addSuccessor(CatchAllBB);
-
- // If the definition of __clang_call_terminate exists in the module, there
- // should be a declaration of std::terminate within the same module, because
- // __clang_call_terminate calls it.
- const auto *StdTerminateFn =
- MF.getMMI().getModule()->getNamedValue(WebAssembly::StdTerminateFn);
- assert(StdTerminateFn && "std::terminate() does not exist in the module");
-
- // Generate a BB in the form of:
- // catch_all
- // call @std::terminate
- // unreachable
- BuildMI(CatchAllBB, Call->getDebugLoc(), TII.get(WebAssembly::CATCH_ALL));
- BuildMI(CatchAllBB, Call->getDebugLoc(), TII.get(WebAssembly::CALL))
- .addGlobalAddress(StdTerminateFn);
- BuildMI(CatchAllBB, Call->getDebugLoc(), TII.get(WebAssembly::UNREACHABLE));
- }
-
- return true;
-}
Index: llvm/lib/Target/WebAssembly/WebAssembly.h
===================================================================
--- llvm/lib/Target/WebAssembly/WebAssembly.h
+++ llvm/lib/Target/WebAssembly/WebAssembly.h
@@ -49,7 +49,6 @@
FunctionPass *createWebAssemblyLateEHPrepare();
FunctionPass *createWebAssemblyCFGSort();
FunctionPass *createWebAssemblyCFGStackify();
-FunctionPass *createWebAssemblyHandleEHTerminatePads();
FunctionPass *createWebAssemblyExplicitLocals();
FunctionPass *createWebAssemblyLowerBrUnless();
FunctionPass *createWebAssemblyRegNumbering();
@@ -76,7 +75,6 @@
void initializeWebAssemblyExceptionInfoPass(PassRegistry &);
void initializeWebAssemblyCFGSortPass(PassRegistry &);
void initializeWebAssemblyCFGStackifyPass(PassRegistry &);
-void initializeWebAssemblyHandleEHTerminatePadsPass(PassRegistry &);
void initializeWebAssemblyExplicitLocalsPass(PassRegistry &);
void initializeWebAssemblyLowerBrUnlessPass(PassRegistry &);
void initializeWebAssemblyRegNumberingPass(PassRegistry &);
Index: llvm/lib/Target/WebAssembly/CMakeLists.txt
===================================================================
--- llvm/lib/Target/WebAssembly/CMakeLists.txt
+++ llvm/lib/Target/WebAssembly/CMakeLists.txt
@@ -22,7 +22,6 @@
WebAssemblyCFGSort.cpp
WebAssemblyDebugFixup.cpp
WebAssemblyDebugValueManager.cpp
- WebAssemblyHandleEHTerminatePads.cpp
WebAssemblyLateEHPrepare.cpp
WebAssemblyExceptionInfo.cpp
WebAssemblyExplicitLocals.cpp
Index: llvm/lib/CodeGen/WasmEHPrepare.cpp
===================================================================
--- llvm/lib/CodeGen/WasmEHPrepare.cpp
+++ llvm/lib/CodeGen/WasmEHPrepare.cpp
@@ -297,8 +297,8 @@
}
}
- // Cleanup pads w/o __clang_call_terminate call do not have any of
- // wasm.get.exception() or wasm.get.ehselector() calls. We need to do nothing.
+ // Cleanup pads do not have any of wasm.get.exception() or
+ // wasm.get.ehselector() calls. We need to do nothing.
if (!GetExnCI) {
assert(!GetSelectorCI &&
"wasm.get.ehselector() cannot exist w/o wasm.get.exception()");
Index: clang/test/CodeGenCXX/wasm-eh.cpp
===================================================================
--- clang/test/CodeGenCXX/wasm-eh.cpp
+++ clang/test/CodeGenCXX/wasm-eh.cpp
@@ -188,13 +188,7 @@
// CHECK: [[TERMINATE_BB]]:
// CHECK-NEXT: %[[CLEANUPPAD1:.*]] = cleanuppad within %[[CLEANUPPAD0]] []
-// CHECK-NEXT: %[[EXN:.*]] = call i8* @llvm.wasm.get.exception(token %[[CLEANUPPAD1]])
-// CHECK-NEXT: call void @__clang_call_terminate(i8* %[[EXN]]) {{.*}} [ "funclet"(token %[[CLEANUPPAD1]]) ]
-// CHECK-NEXT: unreachable
-
-// CHECK-LABEL: define {{.*}} void @__clang_call_terminate(i8* %0)
-// CHECK-NEXT: call i8* @__cxa_begin_catch(i8* %{{.*}})
-// CHECK-NEXT: call void @_ZSt9terminatev()
+// CHECK-NEXT: call void @_ZSt9terminatev() {{.*}} [ "funclet"(token %[[CLEANUPPAD1]]) ]
// CHECK-NEXT: unreachable
// Try-catch with cleanups
@@ -336,7 +330,7 @@
// CHECK: unreachable
// CHECK: %[[CLEANUPPAD7:.*]] = cleanuppad within %[[CLEANUPPAD4]] []
-// CHECK: call void @__clang_call_terminate(i8* %{{.*}}) {{.*}} [ "funclet"(token %[[CLEANUPPAD7]]) ]
+// CHECK: call void @_ZSt9terminatev() {{.*}} [ "funclet"(token %[[CLEANUPPAD7]]) ]
// CHECK: unreachable
// Nested try-catches within a catch
Index: clang/lib/CodeGen/ItaniumCXXABI.cpp
===================================================================
--- clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -515,6 +515,9 @@
: ItaniumCXXABI(CGM, /*UseARMMethodPtrABI=*/true,
/*UseARMGuardVarABI=*/true) {}
void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override;
+ llvm::CallInst *
+ emitTerminateForUnexpectedException(CodeGenFunction &CGF,
+ llvm::Value *Exn) override;
private:
bool HasThisReturn(GlobalDecl GD) const override {
@@ -4640,6 +4643,18 @@
ItaniumCXXABI::emitBeginCatch(CGF, C);
}
+llvm::CallInst *
+WebAssemblyCXXABI::emitTerminateForUnexpectedException(CodeGenFunction &CGF,
+ llvm::Value *Exn) {
+ // Itanium ABI calls __clang_call_terminate(), which __cxa_begin_catch() on
+ // the violating exception to mark it handled, but it is currently hard to do
+ // with wasm EH instruction structure with catch/catch_all, we just call
+ // std::terminate and ignore the violating exception as in CGCXXABI.
+ // TODO Consider code transformation that makes calling __clang_call_terminate
+ // possible.
+ return CGCXXABI::emitTerminateForUnexpectedException(CGF, Exn);
+}
+
/// Register a global destructor as best as we know how.
void XLCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
llvm::FunctionCallee dtor,
Index: clang/lib/CodeGen/CGException.cpp
===================================================================
--- clang/lib/CodeGen/CGException.cpp
+++ clang/lib/CodeGen/CGException.cpp
@@ -1552,17 +1552,8 @@
CurrentFuncletPad = Builder.CreateCleanupPad(ParentPad);
// Emit the __std_terminate call.
- llvm::Value *Exn = nullptr;
- // In case of wasm personality, we need to pass the exception value to
- // __clang_call_terminate function.
- if (getLangOpts().CPlusPlus &&
- EHPersonality::get(*this).isWasmPersonality()) {
- llvm::Function *GetExnFn =
- CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
- Exn = Builder.CreateCall(GetExnFn, CurrentFuncletPad);
- }
llvm::CallInst *terminateCall =
- CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
+ CGM.getCXXABI().emitTerminateForUnexpectedException(*this, nullptr);
terminateCall->setDoesNotReturn();
Builder.CreateUnreachable();
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