<br><br><div class="gmail_quote">2010/1/22 James Williams <span dir="ltr"><<a href="mailto:junk@giantblob.com">junk@giantblob.com</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br><br><div class="gmail_quote">2010/1/22 Duncan Sands <span dir="ltr"><<a href="mailto:baldrick@free.fr" target="_blank">baldrick@free.fr</a>></span><div class="im"><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi James,<div><br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
I've been trying to get a minimal test function to work, which simply invokes _Unwind_RaiseException with a single clean-up landing pad. However. when I run it my personality function is not getting called - _Unwind_RaiseException simply returns apparently doing nothing. Looking at the x86-64 assembly output from llc, I can see this is happening because the personality function is not getting into the DWARF eh table (the landing pad is there though).<br>
</blockquote>
<br></div>
do you mean that the personality function doesn't turn up in the assembler<br>
at all? It should be! Consider the following simplified example:<br></blockquote></div><div><br>Yes - no reference to the personality function at all. I tried Bill Wendling's suggestion to add an i8* null to the llvm.eh.selector.i64 parameter list but I still get no reference to the personality function. Compared to your example my eh table seems to be missing a load of stuff. The complete LLVM generated x86-64 assembler for my function including eh table is:</div>
</div></blockquote><div><br>BTW: I'm using LLVM 2.6 compiled from source on Ubuntu 9.10 in case it's relevant. <br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="gmail_quote"><div><div class="im"><br>
<br> .text<br> .align 16<br> .globl _ZN4N0014Main5test5EN2IO6WriterEiA_l<br> .type _ZN4N0014Main5test5EN2IO6WriterEiA_l,@function<br>_ZN4N0014Main5test5EN2IO6WriterEiA_l: # @_ZN4N0014Main5test5EN2IO6WriterEiA_l<br>
.Leh_func_begin153:<br>.Lfunc_begin153:<br>.LBB153_0: # %entry<br> subq $56, %rsp<br></div>.Llabel294:<div class="im"><br>.LBB153_1:<br> movq %rdi, 24(%rsp)<br>
movq %rsi, 48(%rsp)<br>
movl %edx, 44(%rsp)<br> movq %rcx, 32(%rsp)<br>.LBB153_2: # %.try_body<br> movq 32(%rsp), %rdi<br></div>.Llabel291:<div class="im"><br> addq $16, %rdi<br>
xorb %al, %al<br>
call _Unwind_RaiseException<br></div>.Llabel292:<div class="im"><br> jmp .LBB153_4<br>.LBB153_3: # %.finally_pad<br></div>.Llabel293:<div class="im"><br> movq %rax, 16(%rsp)<br>
testq %rdx, %rdx<br>
setne %al<br> movzbl %al, %eax<br> movq %rax, (%rsp)<br>.LBB153_4: # %.finally_handler<br> movl $.L__string_27, %edi<br> xorb %al, %al<br> call printf<br>
xorl %eax, %eax<br> addq $56, %rsp<br> ret<br> .size _ZN4N0014Main5test5EN2IO6WriterEiA_l, .-_ZN4N0014Main5test5EN2IO6WriterEiA_l<br>.Lfunc_end153:<br>.Leh_func_end153:<br></div><div class="im"> .section .gcc_except_table,"a",@progbits<br>
.align 4<br></div><div class="im">GCC_except_table153:<br> .byte 0x0 # Padding<br>.Lexception153:<br> .byte 0xFF # @LPStart format (DW_EH_PE_omit)<br>
.byte 0x0 # @TType format (DW_EH_PE_absptr)<br></div> .uleb128 28 # @TType base offset<div class="im"><br> .byte 0x3 # Call site format (DW_EH_PE_udata4)<br>
</div>
.uleb128 26 # Call site table size<br> .long .Llabel291-.Leh_func_begin153 # Region start<br> .long .Llabel292-.Llabel291 # Region length<br>
.long .Llabel293-.Leh_func_begin153 # Landing pad<br> .uleb128 0 # Action<br> .long .Llabel292-.Leh_func_begin153 # Region start<br> .long .Leh_func_end153-.Llabel292 # Region length<br>
.long 0x0 # Landing pad<div><div></div><div class="h5"><br> .uleb128 0 # Action<br> .align 4<br><br><br><br></div></div></div><div>
<div></div><div class="h5"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>
declare void @g()<br>
<br>
define void @f() {<br>
e:<br>
invoke void @g()<br>
to label %c unwind label %u<br>
<br>
c: ; preds = %e<br>
ret void<br>
<br>
u: ; preds = %e<br>
%ptr = tail call i8* @llvm.eh.exception() nounwind ; <i8*> [#uses=1]<br>
%select = tail call i32 (i8*, i8*, ...)* @llvm.eh.selector(i8* %ptr, i8* bitcast (i32 (...)* @personality to i8*)) nounwind ; <i32> [#uses=0]<br>
ret void<br>
}<br>
<br>
declare i8* @llvm.eh.exception() nounwind readonly<br>
<br>
declare i32 @llvm.eh.selector(i8*, i8*, ...) nounwind<br>
<br>
declare i32 @personality(...)<br>
<br>
<br>
<br>
This compiles down to the following, which has a "cleanup" noted in the<br>
dwarf eh table, and has the personality function recorded in the CIE.<br>
This is with llc from top-of-tree. Do you see something different?<br>
<br>
Ciao,<br>
<br>
Duncan.<br>
<br>
<br>
<br>
.file "selector.ll"<br>
<br>
<br>
.text<br>
.align 16<br>
.globl f<br>
.type f,@function<br>
f: # @f<br>
.Leh_func_begin1:<br>
# BB#0: # %e<br>
subq $8, %rsp<br>
.Llabel4:<br>
.Llabel1:<br>
callq g<br>
.Llabel2:<br>
# BB#1: # %c<br>
addq $8, %rsp<br>
ret<br>
.LBB1_2:<br>
# %u<br>
.Llabel3:<br>
addq $8, %rsp<br>
ret<br>
.size f, .-f<br>
.Leh_func_end1:<div><br>
.section .gcc_except_table,"a",@progbits<br>
.align 4<br></div>
GCC_except_table1:<br>
.byte 0<br>
# Padding<br>
.byte 0<br>
# Padding<br>
.Lexception1:<br>
.byte 255<br>
# @LPStart format (omit)<br>
.byte 0<br>
# @TType format (absptr)<br>
.uleb128 15 # @TType base offset<br>
.byte 3<br>
# Call site format (udata4)<br>
.uleb128 13 # Call site table size<br>
.long .Llabel1-.Leh_func_begin1 # Region start<br>
.long .Llabel2-.Llabel1 # Region length<br>
.long .Llabel3-.Leh_func_begin1 # Landing pad<br>
.uleb128 0 # Action<br>
.align 4<br>
.section .eh_frame,"aw",@progbits<br>
.LEH_frame0:<br>
.Lsection_eh_frame:<br>
.Leh_frame_common:<br>
.long .Leh_frame_common_end-.Leh_frame_common_begin # Length of Common Information Entry<br>
.Leh_frame_common_begin:<br>
.long 0<br>
# CIE Identifier Tag<br>
.byte 1<br>
# CIE Version<br>
.asciz "zPLR" # CIE Augmentation<br>
.uleb128 1 # CIE Code Alignment Factor<br>
.sleb128 -8 # CIE Data Alignment Factor<br>
.byte 16<br>
# CIE Return Address Column<br>
.uleb128 7 # Augmentation Size<br>
.byte 27<br>
# Personality (pcrel sdata4)<br>
.Lpersonalityref_addr1_0:<br>
.long personality-.Lpersonalityref_addr1_0 # Personality<br>
.byte 27<br>
# LSDA Encoding (pcrel sdata4)<br>
.byte 27<br>
# FDE Encoding (pcrel sdata4)<br>
.byte 12<br>
# DW_CFA_def_cfa<br>
.uleb128 7 # Register<br>
.uleb128 8 # Offset<br>
.byte 144<br>
# DW_CFA_offset + Reg (16)<br>
.uleb128 1 # Offset<br>
.align 8<br>
.Leh_frame_common_end:<br>
<br>
.Lf.eh:<br>
.long .Leh_frame_end1-.Leh_frame_begin1 # Length of Frame Information Entry<br>
.Leh_frame_begin1:<br>
.long .Leh_frame_begin1-.Leh_frame_common # FDE CIE offset<br>
.long .Leh_func_begin1-. # FDE initial location<br>
.long .Leh_func_end1-.Leh_func_begin1 # FDE address range<br>
.uleb128 8 # Augmentation size<br>
.quad .Lexception1-. # Language Specific Data Area<br>
.byte 4<br>
# DW_CFA_advance_loc4<br>
.long .Llabel4-.Leh_func_begin1<br>
.byte 14<br>
# DW_CFA_def_cfa_offset<br>
.uleb128 16 # Offset<br>
.align 8<br>
.Leh_frame_end1:<br>
<br>
<br>
.section .note.GNU-stack,"",@progbits<br>
<br>
</blockquote></div></div></div><br>
</blockquote></div><br>