I am trying to get exceptions working with llvm for a very simple example that I can use later, but I'm having some real difficulties and I'm not sure why.
I got clang to give me the following llir code that I go to MCJIT
; llvm-as c++exn.ll && llvm-ld -native c++exn.bc -lstdc++.6 && ./a.out %"class.std::ios_base::Init" = type { i8 } %"class.std::basic_ostream" = type { i32 (...)**, %"class.std::basic_ios" } %"class.std::basic_ios" = type { %"class.std::ios_base", %"class.std::basic_ostream"*, i8, i8, %"class.std::basic_streambuf"*, %"class.std::ctype"*, %"class.std::num_put"*, %"class.std::num_get"* } %"class.std::ios_base" = type { i32 (...)**, i64, i64, i32, i32, i32, %"struct.std::ios_base::_Callback_list"*, %"struct.std::ios_base::_Words", [8 x %"struct.std::ios_base::_Words"], i32, %"struct.std::ios_base::_Words"*, %"class.std::locale" } %"struct.std::ios_base::_Callback_list" = type { %"struct.std::ios_base::_Callback_list"*, void (i32, %"class.std::ios_base"*, i32)*, i32, i32 } %"struct.std::ios_base::_Words" = type <{ i8*, i32, [4 x i8] }> %"class.std::locale" = type { %"class.std::locale::_Impl"* } %"class.std::locale::_Impl" = type { i32, %"class.std::locale::facet"**, i64, %"class.std::locale::facet"**, i8** } %"class.std::locale::facet" = type <{ i32 (...)**, i32, [4 x i8] }> %"class.std::basic_streambuf" = type { i32 (...)**, i8*, i8*, i8*, i8*, i8*, i8*, %"class.std::locale" } %"class.std::ctype" = type <{ %"class.std::locale::facet.base", [4 x i8], i32*, i8, [7 x i8], i32*, i32*, i16*, i8, [256 x i8], [256 x i8], i8, [6 x i8] }> %"class.std::locale::facet.base" = type <{ i32 (...)**, i32 }> %"class.std::num_put" = type { %"class.std::locale::facet.base", [4 x i8] } %"class.std::num_get" = type { %"class.std::locale::facet.base", [4 x i8] } %class.new_exception = type { %"class.std::exception" } %"class.std::exception" = type { i32 (...)** } $_ZN13new_exceptionC2Ev = comdat any $_ZN13new_exceptionD2Ev = comdat any $__clang_call_terminate = comdat any $_ZNSt9exceptionC2Ev = comdat any $_ZN13new_exceptionD0Ev = comdat any $_ZTS13new_exception = comdat any $_ZTI13new_exception = comdat any $_ZTV13new_exception = comdat any @_ZStL8__ioinit = internal global %"class.std::ios_base::Init" zeroinitializer, align 1 @_ZTVN10__cxxabiv120__si_class_type_infoE = external global i8* @_ZTS13new_exception = linkonce_odr constant [16 x i8] c"13new_exception\00", comdat @_ZTISt9exception = external constant i8* @_ZTI13new_exception = linkonce_odr constant { i8*, i8*, i8* } { i8* bitcast (i8** getelementptr inbounds (i8*, i8** @_ZTVN10__cxxabiv120__si_class_type_infoE, i64 2) to i8*), i8* getelementptr inbounds ([16 x i8], [16 x i8]* @_ZTS13new_exception, i32 0, i32 0), i8* bitcast (i8** @_ZTISt9exception to i8*) }, comdat @_ZSt4cout = external global %"class.std::basic_ostream", align 8 @.str = private unnamed_addr constant [11 x i8] c"caught !!!\00", align 1 @_ZTV13new_exception = linkonce_odr unnamed_addr constant [5 x i8*] [i8* null, i8* bitcast ({ i8*, i8*, i8* }* @_ZTI13new_exception to i8*), i8* bitcast (void (%class.new_exception*)* @_ZN13new_exceptionD2Ev to i8*), i8* bitcast (void (%class.new_exception*)* @_ZN13new_exceptionD0Ev to i8*), i8* bitcast (i8* (%"class.std::exception"*)* @_ZNKSt9exception4whatEv to i8*)], comdat, align 8 @_ZTVSt9exception = external unnamed_addr constant [5 x i8*] @llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @_GLOBAL__sub_I_runtime_gen.cpp, i8* null }] ; Function Attrs: uwtable define internal void @__cxx_global_var_init() #0 { call void @_ZNSt8ios_base4InitC1Ev(%"class.std::ios_base::Init"* @_ZStL8__ioinit) %1 = call i32 @atexit(void ()* @__dtor__ZStL8__ioinit) #2 ret void } declare void @_ZNSt8ios_base4InitC1Ev(%"class.std::ios_base::Init"*) #1 declare void @_ZNSt8ios_base4InitD1Ev(%"class.std::ios_base::Init"*) #1 ; Function Attrs: uwtable define internal void @__dtor__ZStL8__ioinit() #0 { call void @_ZNSt8ios_base4InitD1Ev(%"class.std::ios_base::Init"* @_ZStL8__ioinit) ret void } ; Function Attrs: nounwind declare i32 @atexit(void ()*) #2 ; Function Attrs: uwtable define void @_Z5functv() #0 { %1 = call i8* @__cxa_allocate_exception(i64 8) #2 %2 = bitcast i8* %1 to %class.new_exception* %3 = bitcast %class.new_exception* %2 to i8* call void @llvm.memset.p0i8.i64(i8* %3, i8 0, i64 8, i32 16, i1 false) call void @_ZN13new_exceptionC2Ev(%class.new_exception* %2) #2 call void @__cxa_throw(i8* %1, i8* bitcast ({ i8*, i8*, i8* }* @_ZTI13new_exception to i8*), i8* bitcast (void (%class.new_exception*)* @_ZN13new_exceptionD2Ev to i8*)) #11 unreachable ; No predecessors! ret void } declare i8* @__cxa_allocate_exception(i64) ; Function Attrs: argmemonly nounwind declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) #3 ; Function Attrs: inlinehint nounwind uwtable define linkonce_odr void @_ZN13new_exceptionC2Ev(%class.new_exception* %this) unnamed_addr #4 comdat align 2 { %1 = alloca %class.new_exception*, align 8 store %class.new_exception* %this, %class.new_exception** %1, align 8 %2 = load %class.new_exception*, %class.new_exception** %1, align 8 %3 = bitcast %class.new_exception* %2 to %"class.std::exception"* call void @_ZNSt9exceptionC2Ev(%"class.std::exception"* %3) #2 %4 = bitcast %class.new_exception* %2 to i32 (...)*** store i32 (...)** bitcast (i8** getelementptr inbounds ([5 x i8*], [5 x i8*]* @_ZTV13new_exception, i64 0, i64 2) to i32 (...)**), i32 (...)*** %4, align 8 ret void } ; Function Attrs: inlinehint nounwind uwtable define linkonce_odr void @_ZN13new_exceptionD2Ev(%class.new_exception* %this) unnamed_addr #4 comdat align 2 { %1 = alloca %class.new_exception*, align 8 store %class.new_exception* %this, %class.new_exception** %1, align 8 %2 = load %class.new_exception*, %class.new_exception** %1, align 8 %3 = bitcast %class.new_exception* %2 to %"class.std::exception"* call void @_ZNSt9exceptionD2Ev(%"class.std::exception"* %3) #2 ret void } declare void @__cxa_throw(i8*, i8*, i8*) ; Function Attrs: uwtable define void @_Z4ctchv() #0 personality i8* bitcast (i32 (...)* @__gxx_personality_seh0 to i8*) { %1 = alloca i8* %2 = alloca i32 %o = alloca %class.new_exception*, align 8 invoke void @_Z5functv() to label %3 unwind label %4 ; <label>:3 ; preds = %0 br label %20 ; <label>:4 ; preds = %0 %5 = landingpad { i8*, i32 } catch i8* bitcast ({ i8*, i8*, i8* }* @_ZTI13new_exception to i8*) %6 = extractvalue { i8*, i32 } %5, 0 store i8* %6, i8** %1, align 8 %7 = extractvalue { i8*, i32 } %5, 1 store i32 %7, i32* %2, align 4 br label %8 ; <label>:8 ; preds = %4 %9 = load i32, i32* %2, align 4 %10 = call i32 @llvm.eh.typeid.for(i8* bitcast ({ i8*, i8*, i8* }* @_ZTI13new_exception to i8*)) #2 %11 = icmp eq i32 %9, %10 br i1 %11, label %12, label %26 ; <label>:12 ; preds = %8 %13 = load i8*, i8** %1, align 8 %14 = call i8* @__cxa_begin_catch(i8* %13) #2 %15 = bitcast i8* %14 to %class.new_exception* store %class.new_exception* %15, %class.new_exception** %o, align 8 %16 = invoke dereferenceable(272) %"class.std::basic_ostream"* @_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc(%"class.std::basic_ostream"* dereferenceable(272) @_ZSt4cout, i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str, i32 0, i32 0)) to label %17 unwind label %21 ; <label>:17 ; preds = %12 %18 = invoke dereferenceable(272) %"class.std::basic_ostream"* @_ZNSolsEPFRSoS_E(%"class.std::basic_ostream"* %16, %"class.std::basic_ostream"* (%"class.std::basic_ostream"*)* @_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_) to label %19 unwind label %21 ; <label>:19 ; preds = %17 call void @__cxa_end_catch() br label %20 ; <label>:20 ; preds = %19, %3 ret void ; <label>:21 ; preds = %17, %12 %22 = landingpad { i8*, i32 } cleanup %23 = extractvalue { i8*, i32 } %22, 0 store i8* %23, i8** %1, align 8 %24 = extractvalue { i8*, i32 } %22, 1 store i32 %24, i32* %2, align 4 invoke void @__cxa_end_catch() to label %25 unwind label %31 ; <label>:25 ; preds = %21 br label %26 ; <label>:26 ; preds = %25, %8 %27 = load i8*, i8** %1, align 8 %28 = load i32, i32* %2, align 4 %29 = insertvalue { i8*, i32 } undef, i8* %27, 0 %30 = insertvalue { i8*, i32 } %29, i32 %28, 1 resume { i8*, i32 } %30 ; <label>:31 ; preds = %21 %32 = landingpad { i8*, i32 } catch i8* null %33 = extractvalue { i8*, i32 } %32, 0 call void @__clang_call_terminate(i8* %33) #12 unreachable } declare i32 @__gxx_personality_seh0(...) ; Function Attrs: nounwind readnone declare i32 @llvm.eh.typeid.for(i8*) #5 declare i8* @__cxa_begin_catch(i8*) declare dereferenceable(272) %"class.std::basic_ostream"* @_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc(%"class.std::basic_ostream"* dereferenceable(272), i8*) #1 declare dereferenceable(272) %"class.std::basic_ostream"* @_ZNSolsEPFRSoS_E(%"class.std::basic_ostream"*, %"class.std::basic_ostream"* (%"class.std::basic_ostream"*)*) #1 declare dereferenceable(272) %"class.std::basic_ostream"* @_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_(%"class.std::basic_ostream"* dereferenceable(272)) #1 declare void @__cxa_end_catch() ; Function Attrs: noinline noreturn nounwind define linkonce_odr hidden void @__clang_call_terminate(i8*) #6 comdat { %2 = call i8* @__cxa_begin_catch(i8* %0) #2 call void @_ZSt9terminatev() #12 unreachable } declare void @_ZSt9terminatev() ; Function Attrs: norecurse uwtable define i32 @main() #7 { call void @_Z4ctchv() ret i32 0 } ; Function Attrs: nounwind uwtable define linkonce_odr void @_ZNSt9exceptionC2Ev(%"class.std::exception"* %this) unnamed_addr #8 comdat align 2 { %1 = alloca %"class.std::exception"*, align 8 store %"class.std::exception"* %this, %"class.std::exception"** %1, align 8 %2 = load %"class.std::exception"*, %"class.std::exception"** %1, align 8 %3 = bitcast %"class.std::exception"* %2 to i32 (...)*** store i32 (...)** bitcast (i8** getelementptr inbounds ([5 x i8*], [5 x i8*]* @_ZTVSt9exception, i64 0, i64 2) to i32 (...)**), i32 (...)*** %3, align 8 ret void } ; Function Attrs: inlinehint nounwind uwtable define linkonce_odr void @_ZN13new_exceptionD0Ev(%class.new_exception* %this) unnamed_addr #4 comdat align 2 { %1 = alloca %class.new_exception*, align 8 store %class.new_exception* %this, %class.new_exception** %1, align 8 %2 = load %class.new_exception*, %class.new_exception** %1, align 8 call void @_ZN13new_exceptionD2Ev(%class.new_exception* %2) #2 %3 = bitcast %class.new_exception* %2 to i8* call void @_ZdlPv(i8* %3) #13 ret void } ; Function Attrs: nounwind declare i8* @_ZNKSt9exception4whatEv(%"class.std::exception"*) #9 ; Function Attrs: nobuiltin nounwind declare void @_ZdlPv(i8*) #10 ; Function Attrs: nounwind declare void @_ZNSt9exceptionD2Ev(%"class.std::exception"*) #9 ; Function Attrs: uwtable define internal void @_GLOBAL__sub_I_runtime_gen.cpp() #0 { call void @__cxx_global_var_init() ret void } attributes #0 = { uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" } attributes #1 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" } attributes #2 = { nounwind } attributes #3 = { argmemonly nounwind } attributes #4 = { inlinehint nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" } attributes #5 = { nounwind readnone } attributes #6 = { noinline noreturn nounwind } attributes #7 = { norecurse uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" } attributes #8 = { nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" } attributes #9 = { nounwind "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" } attributes #10 = { nobuiltin nounwind "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" } attributes #11 = { noreturn } attributes #12 = { noreturn nounwind } attributes #13 = { builtin nounwind }
This is the llir code generated from the following C ++ code.
#include <iostream> #include <exception> using namespace std; class new_exception : public exception { const char* what() { return "new_exception"; } }; void funct() { throw new_exception(); } void ctch() { try { funct(); } catch(new_exception& o) { std::cout << "caught !!!" << std::endl; } } int main() { ctch(); }
When loading, it compiled MCJIT on windows without problems, but when it starts, when starting with gdb, it stops with the message "RaiseException () ?: Unknown signal".
As far as I know, the exception is handled correctly, "caught" by the code, and therefore should not be a problem.
I use the personality function correctly, I looked through the answers which suggest that using SEH based personality on windows might be wrong. What is the alternative if this is wrong, and why not write the wrong code?
The platform is Windows X86_64
target datalayout = "em:w-i64:64-f80:128-n8:16:32:64-S128" target triple = "x86_64-w64-windows-gnu"