[commit: ghc] master: Correct incorrect free in PE linker (ee2e9ec)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/ee2e9ece388e75ac433097ac726a555a07ae0830/ghc

>---------------------------------------------------------------

commit ee2e9ece388e75ac433097ac726a555a07ae0830
Author: Tamar Christina <tamar at zhox.com>
Date:   Sat Aug 19 08:31:34 2017 +0100

    Correct incorrect free in PE linker
    
    Summary:
    The big-obj support (D3523) had introduced an early free on
    the info structure. Because the pointer is not NULL'd
    and the default of all the utility functions was to the
    standard object format, it all kept working.
    
    The one big-obj test that exists was subjected to a timing issue.
    usually the test ran quickly enough that the allocator hasn't
    had time to reclaim the memory yet, so it still passed.
    
    This corrects it. Also as it so happens, static LLVM libraries
    from mingw-w64 are compiled using big-obj.
    
    Test Plan: ./validate
    
    Reviewers: austin, bgamari, erikd, simonmar
    
    Reviewed By: bgamari
    
    Subscribers: rwbarton, thomie
    
    GHC Trac Issues: #13815, #13093
    
    Differential Revision: https://phabricator.haskell.org/D3862


>---------------------------------------------------------------

ee2e9ece388e75ac433097ac726a555a07ae0830
 rts/linker/PEi386.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/rts/linker/PEi386.c b/rts/linker/PEi386.c
index 22258fe..42e7008 100644
--- a/rts/linker/PEi386.c
+++ b/rts/linker/PEi386.c
@@ -1421,6 +1421,7 @@ ocGetNames_PEi386 ( ObjectCode* oc )
           addr = (char*)cstring_from_COFF_symbol_name(
                                getSymShortName (info, symtab_i),
                                strtab);
+          stgFree (info);
 
           IF_DEBUG(linker,
                    debugBelch("addImportSymbol `%s' => `%s'\n",
@@ -1471,8 +1472,6 @@ ocGetNames_PEi386 ( ObjectCode* oc )
        i += getSymNumberOfAuxSymbols (info, symtab_i);
    }
 
-   stgFree (info);
-
    /* Allocate BSS space */
    SymbolAddr* bss = NULL;
    if (globalBssSize > 0) {
@@ -1570,6 +1569,7 @@ ocGetNames_PEi386 ( ObjectCode* oc )
           if (result != NULL || dllInstance == 0) {
               errorBelch("Could not load `%s'. Reason: %s\n",
                          (char*)dllName, result);
+              stgFree (info);
               return false;
           }
 
@@ -1599,8 +1599,10 @@ ocGetNames_PEi386 ( ObjectCode* oc )
           sname[size-start]='\0';
           stgFree(tmp);
           if (!ghciInsertSymbolTable(oc->fileName, symhash, (SymbolName*)sname,
-                                     addr, false, oc))
+                                     addr, false, oc)) {
+               stgFree (info);
                return false;
+          }
           break;
       }
 
@@ -1617,6 +1619,7 @@ ocGetNames_PEi386 ( ObjectCode* oc )
 
          if (! ghciInsertSymbolTable(oc->fileName, symhash, (SymbolName*)sname, addr,
                                      isWeak, oc)) {
+             stgFree (info);
              return false;
          }
       } else {
@@ -1650,6 +1653,7 @@ ocGetNames_PEi386 ( ObjectCode* oc )
       i += getSymNumberOfAuxSymbols (info, symtab_i);
    }
 
+   stgFree (info);
    return true;
 }