RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2025-01-31 12:41:49 +01:00
Code Issues Projects Releases Wiki Activity

Fix __clang_call_termiante's argument for foreign exceptions

Browse Source 
Summary:
When exceptions are repeatedly thrown in the middle of handling another
exception, we call `__clang_call_terminate` with the exception pointer
(i32) as an argument. But in case of foreign exceptions, we don't have
the pointer, so we call the function with 0. (This requires
`__clang_call_terminate` can deal with 0 argument, which will be done
later)

But previously the 0 argument was not added as a `i32.const 0` but an
immediate by mistake, causing the `call` instruction to take not an i32
but rather an exnref, because an `exnref` is left on top of the value
stack if `br_on_exn` is not taken.

```
block i32
  br_on_exn 0, __cpp_exception
                               ;; exnref is on top of stack now
  i32.const 0                  ;; This was missing!
  call __clang_call_terminate
  unreachable
end
call __clang_call_terminate    ;; This takes i32 extracted by br_on_exn
```

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65475

llvm-svn: 368527
This commit is contained in:
Heejin Ahn 2019-08-11 06:24:07 +00:00
parent c096312f12
commit 01f5818544
2 changed files with 6 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp
View File

@ -233,6 +233,7 @@ bool WebAssemblyLateEHPrepare::removeUnnecessaryUnreachables(
// it. The pseudo instruction will be deleted later.
bool WebAssemblyLateEHPrepare::addExceptionExtraction(MachineFunction &MF) {
const auto &TII = *MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
MachineRegisterInfo &MRI = MF.getRegInfo();
auto *EHInfo = MF.getWasmEHFuncInfo();
SmallVector<MachineInstr *, 16> ExtractInstrs;
SmallVector<MachineInstr *, 8> ToDelete;
@ -339,9 +340,11 @@ bool WebAssemblyLateEHPrepare::addExceptionExtraction(MachineFunction &MF) {
WebAssembly::ClangCallTerminateFn);
assert(ClangCallTerminateFn &&
"There is no __clang_call_terminate() function");
unsigned Reg = MRI.createVirtualRegister(&WebAssembly::I32RegClass);
BuildMI(ElseMBB, DL, TII.get(WebAssembly::CONST_I32), Reg).addImm(0);
BuildMI(ElseMBB, DL, TII.get(WebAssembly::CALL_VOID))
.addGlobalAddress(ClangCallTerminateFn)
.addImm(0);
.addReg(Reg);
BuildMI(ElseMBB, DL, TII.get(WebAssembly::UNREACHABLE));
} else {

3
test/CodeGen/WebAssembly/exception.ll
View File

@ -138,7 +138,8 @@ ehcleanup: ; preds = %entry
; CHECK: catch
; CHECK: block i32
; CHECK: br_on_exn 0, __cpp_exception
; CHECK: call __clang_call_terminate, 0
; CHECK: i32.const ${{.*}}=, 0
; CHECK: call __clang_call_terminate
; CHECK: unreachable
; CHECK: end_block
; CHECK: call __clang_call_terminate