#15723: -prof -fPIC -fexternal-dynamic-refs generates non-PIC relocations for external symbol -------------------------------------+------------------------------------- Reporter: watashi | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 (CodeGen) | Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 | (amd64) Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D5214 Wiki Page: | -------------------------------------+------------------------------------- Changes (by watashi): * differential: => Phab:D5214 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15723#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#15723: -prof -fPIC -fexternal-dynamic-refs generates non-PIC relocations for external symbol -------------------------------------+------------------------------------- Reporter: watashi | Owner: watashi Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 (CodeGen) | Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 | (amd64) Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D5214 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari ): In [changeset:"95ec7c88c7223508db3ba91d6ab9e303d0b062ad/ghc" 95ec7c88/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="95ec7c88c7223508db3ba91d6ab9e303d0b062ad" Generate correct relocation for external cost centre We used to always generate direct access for cost centre labels. We fixed this by generating indirect data load for cost centre defined in external module. Test Plan: The added test used to fail with error message ``` /bin/ld.gold: error: T15723B.o: requires dynamic R_X86_64_PC32 reloc against 'T15723A_foo1_EXPR_cc' which may overflow at runtime; recompile with -fPIC ``` and now passes. Also check that `R_X86_64_PC32` is generated for CostCentre from the same module and `R_X86_64_GOTPCREL` is generated for CostCentre from external module: ``` $ objdump -rdS T15723B.o 0000000000000028 : 28: 48 8d 45 f0 lea -0x10(%rbp),%rax 2c: 4c 39 f8 cmp %r15,%rax 2f: 72 70 jb a1 31: 48 83 ec 08 sub $0x8,%rsp 35: 48 8d 35 00 00 00 00 lea 0x0(%rip),%rsi # 3c 38: R_X86_64_PC32 T15723B_test1_EXPR_cc-0x4 3c: 49 8b bd 60 03 00 00 mov 0x360(%r13),%rdi 43: 31 c0 xor %eax,%eax 45: e8 00 00 00 00 callq 4a 46: R_X86_64_PLT32 pushCostCentre-0x4 4a: 48 83 c4 08 add $0x8,%rsp 4e: 48 ff 40 30 incq 0x30(%rax) 52: 49 89 85 60 03 00 00 mov %rax,0x360(%r13) 59: 48 83 ec 08 sub $0x8,%rsp 5d: 49 8b bd 60 03 00 00 mov 0x360(%r13),%rdi 64: 48 8b 35 00 00 00 00 mov 0x0(%rip),%rsi # 6b 67: R_X86_64_GOTPCREL T15723A_foo1_EXPR_cc-0x4 6b: 31 c0 xor %eax,%eax 6d: e8 00 00 00 00 callq 72 6e: R_X86_64_PLT32 pushCostCentre-0x4 72: 48 83 c4 08 add $0x8,%rsp 76: 48 ff 40 30 incq 0x30(%rax) ``` Reviewers: simonmar, bgamari Reviewed By: simonmar Subscribers: rwbarton, carter GHC Trac Issues: #15723 Differential Revision: https://phabricator.haskell.org/D5214 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15723#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#15723: -prof -fPIC -fexternal-dynamic-refs generates non-PIC relocations for external symbol -------------------------------------+------------------------------------- Reporter: watashi | Owner: watashi Type: bug | Status: closed Priority: normal | Milestone: 8.8.1 Component: Compiler | Version: 8.6.1 (CodeGen) | Resolution: fixed | Keywords: Operating System: Linux | Architecture: x86_64 | (amd64) Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D5214 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari ): In [changeset:"6e96aa2d503ddeeef1fa1f37b45d5c744522b64d/ghc" 6e96aa2/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="6e96aa2d503ddeeef1fa1f37b45d5c744522b64d" Don't use X86_64_ELF_NONPIC_HACK for +RTS -xp Summary: When `+RTS -xp` is passed, when don't need the X86_64_ELF_NONPIC_HACK, becasue the relocation offset should only be out of range if * the object file was not compiled with `-fPIC -fexternal-dynamic-refs`; * ghc generates non-pic code while it should (e.g. #15723) In either case, we should print an error message rather that silently attempt to use a hacky workaround that may not work. This could have made debugging #15723 and #15729 much easier. Test Plan: Run this in a case where ghci used to crash becasue of T15723. Now we see helpful message like: ``` ghc-iserv-prof: R_X86_64_PC32 relocation out of range: stmzm2zi4zi4zi1zmJQn4hNPyYjP5m9AcbI88Ve_ControlziConcurrentziSTMziTMVar_readTMVar_C61n_cc = 9b95ffac ``` Reviewers: simonmar, bgamari, erikd Reviewed By: simonmar, bgamari Subscribers: rwbarton, carter Differential Revision: https://phabricator.haskell.org/D5233 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15723#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler