[GHC] #9351: add ability to version symbols .c for packages with C code
#9351: add ability to version symbols .c for packages with C code -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Keywords: backpack | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Let's consider an example: We have a haskell package with some C code imported in haskell: {{{ // a.h file int get_something(void); // a.c file #include "a.h" int get_something(void) { return 42; } // M.hs file module M where foreign import ccall "a.h get_something" :: IO Int }}} The problem here is we can't mix that package with other packages having global 'get_something' symbol. Sometimes it happens when a package copies part of implementation from another package with .c bits under different haskell namespace. Haskell parts would coexist freely, but not C symbols. Would be great if ghc would export some unique package identifier in a way C code could attach it to all exported symbols making linking possible. Something like that: {{{ // a.h file #include "HsFFI.h" /* #define FOR_HASKELL(__sym) package_id_##__sym */ int FOR_HASKELL(get_something)(void); // a.c file #include "a.h" int FOR_HASKELL(get_something)(void) { return 42; } // M.hs file module M where foreign import ccall-for-haskell "a.h get_something" :: IO Int }}} That way we explicitly mark symbol as inaccessible to external plain C code. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9351 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9351: add ability to version symbols .c for packages with C code -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.8.3 Component: Compiler | Keywords: backpack Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by hvr): Fwiw, I'd rather have a macro for the `.hs` part as well than have yet another FFI calling convention. (it'd be useful in other cases as well, to have the ability to uniformly transform the ABI-level C symbol name; e.g. for GMP, all official function names are prefixed by `__g` prefix at the ABI level) E.g. something like: {{{#!hs foreign import ccall C_PKG_NAME("a.h","get_something") :: IO Int }}} This will, however, require a better CPP than the current traditional CPP mode to work... -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9351#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9351: add ability to version symbols .c for packages with C code -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.8.3 Component: Compiler | Keywords: backpack Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by slyfox): Yeah, it's just an idea of symbol mangling control. Maybe macro introduction better be done on cabal's side? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9351#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9351: add ability to version symbols .c for packages with C code -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.8.3 Component: Compiler | Keywords: backpack Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by duncan): Or a more automagic approach might be to use binutils to rename or hide C symbols. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9351#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9351: add ability to version symbols .c for packages with C code -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: backpack Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by ezyang): duncan: the problem with a more magic approach is that mangling the symbols could break uses of `dlopen` in the compiled objects, since you have no idea if a string is referring to a specific symbol. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9351#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9351: add ability to version symbols .c for packages with C code -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: backpack Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * cc: RyanGlScott (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9351#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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