Allocate bss section within proper range of other sections

Allocate bss section within proper range of other sections:

* when `+RTS -xp` is passed, allocate it contiguously as we did for
  jump islands
* when we mmap the code to lower 2Gb, we should allocate bss section
  there too

This depends on {D5195}

Test Plan:
1. `./validate`

2.

with

```
DYNAMIC_GHC_PROGRAMS = NO
DYNAMIC_BY_DEFAULT = NO
```

`TEST="T15729" make test` passed in both linux and macos.

3.

Also test in a use case where we used to encouter error like:

```
ghc-iserv-prof: R_X86_64_PC32 relocation out of range: (noname) =
b90282ba
```

and now, everything works fine.

Reviewers: simonmar, bgamari, angerman, erikd

Reviewed By: simonmar

Subscribers: rwbarton, carter

GHC Trac Issues: #15729

Differential Revision: https://phabricator.haskell.org/D5219

1 files changed, 4 insertions, 0 deletions

diff --git a/rts/LinkerInternals.h b/rts/LinkerInternals.h
index 04d873ca99..9c34c18aef 100644
--- a/rts/LinkerInternals.h
+++ b/rts/LinkerInternals.h
@@ -193,6 +193,10 @@ typedef struct _ObjectCode {
     unsigned long   first_symbol_extra;
     unsigned long   n_symbol_extras;
 #endif
+    /* Additional memory that is preallocated and contiguous with image
+       which can be used used to relocate bss sections. */
+    char* bssBegin;
+    char* bssEnd;
 
     ForeignExportStablePtr *stable_ptrs;