#11340: linker_unload test fails on ARM -------------------------------------+------------------------------ Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.10.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: arm Type of failure: Runtime crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------ Comment (by bgamari): Interesting, it appears that the linker built a symbol extra for this symbol due to a long jump. With this patch, {{{#!patch diff --git a/rts/Linker.c b/rts/Linker.c index cb90c97..0cf3fe5 100644 --- a/rts/Linker.c +++ b/rts/Linker.c @@ -2731,6 +2731,7 @@ static int ocAllocateSymbolExtras( ObjectCode* oc, int count, int first ) if (oc->symbol_extras != NULL) { memset( oc->symbol_extras, 0, sizeof (SymbolExtra) * count ); + IF_DEBUG(linker, debugBelch("Symbol extras at %p\n", oc->symbol_extras)); } oc->first_symbol_extra = first; @@ -5019,7 +5020,7 @@ do_Elf_Rel_relocations ( ObjectCode* oc, char* ehdrC, int is_target_thm=0, T=0; #endif - IF_DEBUG(linker,debugBelch( "Rel entry %3d is raw(%6p %6p)", + IF_DEBUG(linker,debugBelch( "Rel entry %3d is raw(%6p %6p): ", j, (void*)offset, (void*)info )); if (!info) { IF_DEBUG(linker,debugBelch( " ZERO" )); @@ -5115,6 +5116,9 @@ do_Elf_Rel_relocations ( ObjectCode* oc, char* ehdrC, // The -8 below is to compensate for PC bias offset = (StgWord32) &extra->jumpIsland - P - 8; offset &= ~1; // Clear thumb indicator bit + IF_DEBUG(linker, debugBelch("Made symbol extra %p due to %s\n", + &extra->jumpIsland, + overflow ? "overflow" : "R_ARM_JUMP24 to Thumb target")); } else if (is_target_thm && ELF_R_TYPE(info) == R_ARM_CALL) { StgWord32 cond = (*word & 0xf0000000) >> 28; if (cond == 0xe) { @@ -5123,6 +5127,8 @@ do_Elf_Rel_relocations ( ObjectCode* oc, char* ehdrC, *word = (*word & ~0x01ffffff) | ((offset >> 2) & 0x00ffffff) // imm24 | ((offset & 0x2) << 23); // H + + IF_DEBUG(linker, debugBelch("Changed BL to BLX at %p\n", word)); break; } else { errorBelch("%s: Can't transition from ARM to Thumb when cond != 0xe\n", }}} I see, {{{ Rel entry 49 is raw( 0x21c 0x461c): lookupSymbol: looking up foreignExportStablePtr lookupSymbol: value of foreignExportStablePtr is 0x3ece80c `foreignExportStablePtr' resolves to 0x3ece80c Reloc: P = 0xb6ff7224 S = 0x3ece80c A = 0xebfffffe Made symbol extra 0xb4f6cf70 due to overflow }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11340#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler