48dc110eea
LLD used to handle comdats as if the selection field was always set to IMAGE_COMDAT_SELECT_ANY. This means for obj files produced by `cl /Gy`, LLD would never report a duplicate symbol error. This change: - adds validation for the Selection field (should make no difference in practice for compiler-generated obj inputs) - rejects comdats that have different Selection fields in different obj files (likewise). This is a bit more strict but also more self-consistent thank link.exe (see comment in code) - implements handling for all the selection kinds In practice, compilers only generate comdats with IMAGE_COMDAT_SELECT_NODUPLICATES (LLD now produces duplicate symbol errors for these), IMAGE_COMDAT_SELECT_ANY (no behavior change), and IMAGE_COMDAT_SELECT_LARGEST (for RTTI data; here LLD should no longer create broken executables when linking some TUs with RTTI enabled and some with it disabled – but see below). The implementation of `IMAGE_COMDAT_SELECT_LARGEST` is incomplete: If one SELECT_LARGEST comdat replaces an earlier one, the comdat symbol is replaced correctly, but the old section stays loaded and if /opt:ref is disabled (via /opt:noref or /debug) it's still written to the output. That's not ideal, but better than the current treatment of just picking any one of those comdats. I hope to fix this better later. Fixes most of PR40094. Differential Revision: https://reviews.llvm.org/D57324 llvm-svn: 352590
46 lines
1.8 KiB
ArmAsm
46 lines
1.8 KiB
ArmAsm
# REQUIRES: x86
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# Tests handling of several comdats with "largest" selection type that each
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# has an associative comdat.
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# Create obj files.
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# RUN: sed -e s/TYPE/.byte/ -e s/SIZE/1/ %s | llvm-mc -triple x86_64-pc-win32 -filetype=obj -o %t.1.obj
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# RUN: sed -e s/TYPE/.short/ -e s/SIZE/2/ %s | llvm-mc -triple x86_64-pc-win32 -filetype=obj -o %t.2.obj
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# RUN: sed -e s/TYPE/.long/ -e s/SIZE/4/ %s | llvm-mc -triple x86_64-pc-win32 -filetype=obj -o %t.4.obj
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.section .text$ac, "", associative, symbol
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assocsym:
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.long SIZE
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.section .text$nm, "", largest, symbol
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.globl symbol
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symbol:
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TYPE SIZE
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# Pass the obj files in different orders and check that only the associative
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# comdat of the largest obj file makes it into the output, independent of
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# the order of the obj files on the command line.
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# FIXME: Make these pass when /opt:noref is passed.
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# RUN: lld-link /include:symbol /dll /noentry /nodefaultlib %t.1.obj %t.2.obj %t.4.obj /out:%t.exe
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# RUN: llvm-objdump -s %t.exe | FileCheck --check-prefix=ALL124 %s
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# ALL124: Contents of section .text:
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# ALL124: 180001000 04000000 04000000 ....
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# RUN: lld-link /include:symbol /dll /noentry /nodefaultlib %t.4.obj %t.2.obj %t.1.obj /out:%t.exe
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# RUN: llvm-objdump -s %t.exe | FileCheck --check-prefix=ALL421 %s
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# ALL421: Contents of section .text:
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# ALL421: 180001000 04000000 04000000 ....
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# RUN: lld-link /include:symbol /dll /noentry /nodefaultlib %t.2.obj %t.4.obj %t.1.obj /out:%t.exe
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# RUN: llvm-objdump -s %t.exe | FileCheck --check-prefix=ALL241 %s
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# ALL241: Contents of section .text:
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# ALL241: 180001000 04000000 04000000 ....
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# RUN: lld-link /include:symbol /dll /noentry /nodefaultlib %t.2.obj %t.1.obj /out:%t.exe
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# RUN: llvm-objdump -s %t.exe | FileCheck --check-prefix=JUST21 %s
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# JUST21: Contents of section .text:
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# JUST21: 180001000 02000000 0200 ....
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