BaseTools GCC: add unified GCC linker script for all archs and versions

This unifies all GCC linker scripts into a single parametrised GCC
linker script that can be used for all GCC versions and architectures.

The two parameters that can be set on the linker command line are:
- PECOFF_HEADER_SIZE, this is a build time property of GenFw, but
  its value is different between 32-bit and 64-bit;
- common-page-size, this can be set using -z on the ld command line,
  and controls the value of the COMMONPAGESIZE constant when used in
  a linker script. This value is used for the minimum section alignment.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Tested-by: Liming Gao <liming.gao@intel.com>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18135 6f19259b-4bc3-4df7-8a09-765794883524

BaseTools/Scripts/GccBase.lds

@@ -0,0 +1,63 @@
+/** @file
+
+  Unified linker script for GCC based builds
+
+  Copyright (c) 2010 - 2015, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2015, Linaro Ltd. All rights reserved.<BR>
+
+  This program and the accompanying materials are licensed and made available under
+  the terms and conditions of the BSD License that accompanies this distribution.
+  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php.
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+SECTIONS {
+
+  /*
+   * The PE/COFF binary consists of DOS and PE/COFF headers, and a sequence of
+   * section headers adding up to PECOFF_HEADER_SIZE bytes (which differs
+   * between 32-bit and 64-bit builds). The actual start of the .text section
+   * will be rounded up based on its actual alignment.
+   */
+  . = PECOFF_HEADER_SIZE;
+
+  .text : ALIGN(CONSTANT(COMMONPAGESIZE)) {
+    *(.text .text.* .stub .gnu.linkonce.t.*)
+    *(.rodata .rodata.* .gnu.linkonce.r.*)
+    *(.got .got.*)
+  }
+
+  /*
+   * The alignment of the .data section should be less than or equal to the
+   * alignment of the .text section. This ensures that the relative offset
+   * between these sections is the same in the ELF and the PE/COFF versions of
+   * this binary.
+   */
+  .data : ALIGN(CONSTANT(COMMONPAGESIZE)) {
+    *(.data .data.* .gnu.linkonce.d.*)
+    *(.bss .bss.* *COM*)
+  }
+
+  .eh_frame ALIGN(CONSTANT(COMMONPAGESIZE)) : {
+    KEEP (*(.eh_frame))
+  }
+
+  .rela ALIGN(CONSTANT(COMMONPAGESIZE)) : {
+    *(.rela .rela.*)
+  }
+
+  /DISCARD/ : {
+    *(.note.GNU-stack)
+    *(.gnu_debuglink)
+    *(.interp)
+    *(.dynsym)
+    *(.dynstr)
+    *(.dynamic)
+    *(.hash)
+    *(.comment)
+  }
+}