Hey everybody!
I have been using llvm 2.8 (i know ancient history!) for a backend that i
was implementing. I have been trying to port my patches to latest llvm (svn
build) lately but i have one problem as far as the Exception Handling
mechanism is concerned. It seems that there are no Exception Tables
generated any more such as the one below:
.section .gcc_except_table,"a", at progbits
.align 4
GCC_except_table0:
.Lexception0:
.byte 255 # @LPStart Encoding = omit
.byte 3 # @TType Encoding = udata4
.uleb128 41 # @TType base offset
.byte 3 # Call site Encoding = udata4
.uleb128 39 # Call site table length
.Lset0 = .Leh_func_begin0-.Leh_func_begin0 # Region start
.long .Lset0
.Lset1 = .Ltmp0-.Leh_func_begin0 # Region length
.long .Lset1
.long 0 # Landing pad
.uleb128 0 # Action
.Lset2 = .Ltmp0-.Leh_func_begin0 # Region start
.long .Lset2
.Lset3 = .Ltmp1-.Ltmp0 # Region length
.long .Lset3
.Lset4 = .Ltmp2-.Leh_func_begin0 # Landing pad
.long .Lset4
.uleb128 0 # Action
.Lset5 = .Ltmp1-.Leh_func_begin0 # Region start
.long .Lset5
.Lset6 = .Leh_func_end0-.Ltmp1 # Region length
.long .Lset6
.long 0 # Landing pad
.uleb128 0 # Action
.align 4
I've searched for this but i couldn't find some documentation about the
changes in the EH staff and the documentation on the website is not
complete... Is there any way i can force the generation of these tables in
current LLVM?
Thanks in advance,
Yiannis
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Hi Yiannis,> I have been using llvm 2.8 (i know ancient history!) for a backend that i was > implementing. I have been trying to port my patches to latest llvm (svn build) > lately but i have one problem as far as the Exception Handling mechanism is > concerned. It seems that there are no Exception Tables generated any more such > as the one below:got some example bitcode for which you see this (or, rather, don't see this since the problem is that you are not seeing exception tables)? Ciao, Duncan.> > .section .gcc_except_table,"a", at progbits > .align 4 > GCC_except_table0: > .Lexception0: > .byte 255 # @LPStart Encoding = omit > .byte 3 # @TType Encoding = udata4 > .uleb128 41 # @TType base offset > .byte 3 # Call site Encoding = udata4 > .uleb128 39 # Call site table length > .Lset0 = .Leh_func_begin0-.Leh_func_begin0 # Region start > .long .Lset0 > .Lset1 = .Ltmp0-.Leh_func_begin0 # Region length > .long .Lset1 > .long 0 # Landing pad > .uleb128 0 # Action > .Lset2 = .Ltmp0-.Leh_func_begin0 # Region start > .long .Lset2 > .Lset3 = .Ltmp1-.Ltmp0 # Region length > .long .Lset3 > .Lset4 = .Ltmp2-.Leh_func_begin0 # Landing pad > .long .Lset4 > .uleb128 0 # Action > .Lset5 = .Ltmp1-.Leh_func_begin0 # Region start > .long .Lset5 > .Lset6 = .Leh_func_end0-.Ltmp1 # Region length > .long .Lset6 > .long 0 # Landing pad > .uleb128 0 # Action > .align 4 > > > I've searched for this but i couldn't find some documentation about the changes > in the EH staff and the documentation on the website is not complete... Is there > any way i can force the generation of these tables in current LLVM? > > Thanks in advance, > Yiannis > > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
On 09/02/2011 05:58 PM, Duncan Sands wrote:> Hi Yiannis, > >> I have been using llvm 2.8 (i know ancient history!) for a backend that i was >> implementing. I have been trying to port my patches to latest llvm (svn build) >> lately but i have one problem as far as the Exception Handling mechanism is >> concerned. It seems that there are no Exception Tables generated any more such >> as the one below: > > got some example bitcode for which you see this (or, rather, don't see this > since the problem is that you are not seeing exception tables)? > > Ciao, Duncan. > >> >> .section .gcc_except_table,"a", at progbits >> .align 4 >> GCC_except_table0: >> .Lexception0: >> .byte 255 # @LPStart Encoding = omit >> .byte 3 # @TType Encoding = udata4 >> .uleb128 41 # @TType base offset >> .byte 3 # Call site Encoding = udata4 >> .uleb128 39 # Call site table length >> .Lset0 = .Leh_func_begin0-.Leh_func_begin0 # Region start >> .long .Lset0 >> .Lset1 = .Ltmp0-.Leh_func_begin0 # Region length >> .long .Lset1 >> .long 0 # Landing pad >> .uleb128 0 # Action >> .Lset2 = .Ltmp0-.Leh_func_begin0 # Region start >> .long .Lset2 >> .Lset3 = .Ltmp1-.Ltmp0 # Region length >> .long .Lset3 >> .Lset4 = .Ltmp2-.Leh_func_begin0 # Landing pad >> .long .Lset4 >> .uleb128 0 # Action >> .Lset5 = .Ltmp1-.Leh_func_begin0 # Region start >> .long .Lset5 >> .Lset6 = .Leh_func_end0-.Ltmp1 # Region length >> .long .Lset6 >> .long 0 # Landing pad >> .uleb128 0 # Action >> .align 4 >> >> >> I've searched for this but i couldn't find some documentation about the changes >> in the EH staff and the documentation on the website is not complete... Is there >> any way i can force the generation of these tables in current LLVM? >> >> Thanks in advance, >> Yiannis >>Hi Duncan, Sorry for my omission! I attach an example (test_0.ll). I do: llvm-as < test_0.ll | llc and i get output-llvm28.txt with the 2.8 versions of the tools and i repeat with the latest versions from the svn repo and i get output-llvm30.txt. As you can see there is a: .section .gcc_except_table,"a", at progbits .... in the 2.8 output just below the code segment while there is no such section in the 3.0 case! Thanks again, Yiannis -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: test_0.ll URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20110902/0538c8c5/attachment.ksh> -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: output-llvm30.txt URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20110902/0538c8c5/attachment.txt> -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: output-llvm28.txt URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20110902/0538c8c5/attachment-0001.txt>