March 2014 - ghc-tickets

Re: [GHC] #7684: cgrun071 segfaults
by GHC 22 Mar '14

22 Mar '14

#7684: cgrun071 segfaults ----------------------------------+---------------------------------- Reporter: tibbe | Owner: Type: bug | Status: infoneeded Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: cgrun071 | Blocked By: Blocking: | Related Tickets: ----------------------------------+---------------------------------- Comment (by carter): gcc-llvm I think is the apple version of dragonegg, which uses the proper GCC frontend, but does the code gen with llvm -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7684#comment:50> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7684: cgrun071 segfaults
by GHC 22 Mar '14

22 Mar '14

#7684: cgrun071 segfaults ----------------------------------+---------------------------------- Reporter: tibbe | Owner: Type: bug | Status: infoneeded Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: cgrun071 | Blocked By: Blocking: | Related Tickets: ----------------------------------+---------------------------------- Comment (by tibbe): I think I've figured it out. I've installed the CLI tools that came with XCode 4.6. Here's the gcc that's included: {{{ $ gcc --version i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00) }}} So this is a LLVM-based GCC (i.e. clang). This GCC indeed produces incorrect code for `popcnt.c`: {{{ #!asm _hs_popcnt8: Leh_func_begin1: pushq %rbp Ltmp0: movq %rsp, %rbp Ltmp1: leaq _popcount_tab(%rip), %rax movzbl (%rdi,%rax), %eax popq %rbp ret }}} Note how the argument is not zero extended when it's used to compute and address in `_popcount_tab`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7684#comment:49> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7684: cgrun071 segfaults
by GHC 22 Mar '14

22 Mar '14

#7684: cgrun071 segfaults ----------------------------------+---------------------------------- Reporter: tibbe | Owner: Type: bug | Status: infoneeded Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: cgrun071 | Blocked By: Blocking: | Related Tickets: ----------------------------------+---------------------------------- Comment (by tibbe): Now I'm confused. Both GCC 4.2 (apple-gcc42 from Homebrew) and GCC 4.9 create the correctly zero extended code for `hs_popcnt8`: GCC 4.2 {{{ #!asm _hs_popcnt8: LFB112: pushq %rbp LCFI0: movq %rsp, %rbp LCFI1: movzbl %dil, %edi leaq _popcount_tab(%rip), %rax movzbl (%rdi,%rax), %eax leave ret }}} GCC 4.9: {{{ #!asm _hs_popcnt8: LFB110: leaq _popcount_tab(%rip), %rax movzbl %dil, %edi movzbl (%rax,%rdi), %eax ret }}} Exact GCC versions: {{{ $ gcc-4.2 --version i686-apple-darwin11-gcc-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5666) (dot 3) ... $ gcc-4.9 --version gcc-4.9 (GCC) 4.9.0 20140223 (experimental) ... }}} Perhaps this bug was fixed in some release of GCC 4.2? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7684#comment:48> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7684: cgrun071 segfaults
by GHC 22 Mar '14

22 Mar '14

#7684: cgrun071 segfaults ----------------------------------+---------------------------------- Reporter: tibbe | Owner: Type: bug | Status: infoneeded Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: cgrun071 | Blocked By: Blocking: | Related Tickets: ----------------------------------+---------------------------------- Comment (by tibbe): I've attached the assembly output for `popcnt.c` (in ghc-prim) and a small C test program, `test.c`, for GCC 4.2 and GCC 4.9, respectively. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7684#comment:47> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7684: cgrun071 segfaults
by GHC 22 Mar '14

22 Mar '14

#7684: cgrun071 segfaults ----------------------------------+---------------------------------- Reporter: tibbe | Owner: Type: bug | Status: infoneeded Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: cgrun071 | Blocked By: Blocking: | Related Tickets: ----------------------------------+---------------------------------- Comment (by tibbe): Replying to [comment:42 simonmar]: > Well, one bug is that in `emitPopCntCall` we don't cast the argument to the correct width. I don't think it should. The `MO_PopCnt` `MachOp` that's emitted by `emitPopCntCall` also takes the width as an argument. The reason we pass the width all the way down to the native and LLVM code generators is to avoid doing any narrowing, as we can emit a `popcnt` instruction that looks at just part of the word (e.g. `popcnt %ax,%ax`). If we end up not using the the dedicated instruction, and we're using GCC 4.2 which doesn't do the narrowing correctly, then we'd have to do the narrowing ourselves before calling the C fallback. I think we have two choices in working around the buggy behavior of GCC 4.2: 1. Change the function prototype as rwbarton suggested. 2. Do some narrowing in the native code generator before emitting the call to the C function. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7684#comment:46> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2283: WIndows: loading objects that refer to DLL symbols
by GHC 22 Mar '14

22 Mar '14

#2283: WIndows: loading objects that refer to DLL symbols ---------------------------------+------------------------------------ Reporter: simonmar | Owner: Type: bug | Status: patch Priority: highest | Milestone: 7.8.1 Component: GHCi | Version: 7.8.1-rc2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: #7097 #7568 ---------------------------------+------------------------------------ Comment (by Austin Seipp <austin@…>): In [changeset:"7a1c85113dd082153cc07f4792216beaf34daeeb/ghc"]: {{{ #!CommitTicketReference repository="ghc" revision="7a1c85113dd082153cc07f4792216beaf34daeeb" linker: Fix indirect calls for x86_64 windows (#2283) Signed-off-by: Austin Seipp <austin(a)well-typed.com> }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2283#comment:22> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7684: cgrun071 segfaults
by GHC 20 Mar '14

20 Mar '14

#7684: cgrun071 segfaults ----------------------------------+---------------------------------- Reporter: tibbe | Owner: Type: bug | Status: infoneeded Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: cgrun071 | Blocked By: Blocking: | Related Tickets: ----------------------------------+---------------------------------- Comment (by simonmar): With a `MO_UU_Conv` `MachOp`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7684#comment:45> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8693: dyn way broken on powerpc
by GHC 20 Mar '14

20 Mar '14

#8693: dyn way broken on powerpc ----------------------------+---------------------------------------- Reporter: trommler | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.7 Keywords: | Operating System: Linux Architecture: powerpc | Type of failure: Building GHC failed Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------+---------------------------------------- Building GHC with dynamic enabled I see lots of the following errors on powerpc (32 bit): {{{ [ 1679s] /tmp/ghc19669_0/ghc19669_6.s: Assembler messages: [ 1679s] [ 1679s] /tmp/ghc19669_0/ghc19669_6.s:39625:0: [ 1679s] Error: operand out of range (0x000000000000b700 is not between 0xffffffffffff8000 and 0x0000000000007fff) ... [ 1679s] /tmp/ghc19669_0/ghc19669_6.s:43936:0: [ 1679s] Error: operand out of range (0x0000000000008018 is not between 0xffffffffffff8000 and 0x0000000000007fff) [ 1679s] make[1]: *** [libraries/time/dist- install/build/Data/Time/Format.o] Error 1 [ 1679s] make[1]: *** Deleting file `libraries/time/dist- install/build/Data/Time/Format.o' }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8693> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7684: cgrun071 segfaults
by GHC 20 Mar '14

20 Mar '14

#7684: cgrun071 segfaults ----------------------------------+---------------------------------- Reporter: tibbe | Owner: Type: bug | Status: infoneeded Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: cgrun071 | Blocked By: Blocking: | Related Tickets: ----------------------------------+---------------------------------- Comment (by tibbe): Replying to [comment:42 simonmar]: > Well, one bug is that in `emitPopCntCall` we don't cast the argument to the correct width. The `-dcmm-lint` should catch it, because the argument width isn't the same as the primop is expecting, but the Cmm linter doesn't check the arguments of prim calls (that's another bug). How would one cast the argument in the `emitPopCntCall`? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7684#comment:44> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7684: cgrun071 segfaults
by GHC 20 Mar '14

20 Mar '14

#7684: cgrun071 segfaults ----------------------------------+---------------------------------- Reporter: tibbe | Owner: Type: bug | Status: infoneeded Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: cgrun071 | Blocked By: Blocking: | Related Tickets: ----------------------------------+---------------------------------- Comment (by tibbe): simonmar, how would one cast the argument in the `emitPopCntCall`? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7684#comment:44> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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