[U-Boot] [PATCH 17/17] 85xx: Use gc-sections to reduce image size

[Peter Tyser]

On an XPedite5370 over 11KBytes were saved:
  Before:
       text	   data	    bss	    dec	    hex	filename
   332456	  33364	  33476	 399296	  617c0	./u-boot

  After:
      text	   data	    bss	    dec	    hex	filename
   321075	  33836	  33476	 388387	  5ed23	./u-boot

Signed-off-by: Peter Tyser <ptyser at xes-inc.com>
CC: Kumar Gala <galak at kernel.crashing.org>
---
 arch/powerpc/cpu/mpc85xx/config.mk  |    4 +++
 arch/powerpc/cpu/mpc85xx/u-boot.lds |   52 +++++++----------------------------
 2 files changed, 14 insertions(+), 42 deletions(-)

diff --git a/arch/powerpc/cpu/mpc85xx/config.mk b/arch/powerpc/cpu/mpc85xx/config.mk
index f07d920..ce4376b 100644
--- a/arch/powerpc/cpu/mpc85xx/config.mk
+++ b/arch/powerpc/cpu/mpc85xx/config.mk
@@ -25,6 +25,10 @@ PLATFORM_RELFLAGS += -fPIC -meabi
 
 PLATFORM_CPPFLAGS += -ffixed-r2 -Wa,-me500 -msoft-float -mno-string
 
+# Enable gc-sections to enable generation of smaller images.
+PLATFORM_LDFLAGS += --gc-sections
+PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections
+
 # -mspe=yes is needed to have -mno-spe accepted by a buggy GCC;
 # see "[PATCH,rs6000] make -mno-spe work as expected" on
 # http://gcc.gnu.org/ml/gcc-patches/2008-04/msg00311.html
diff --git a/arch/powerpc/cpu/mpc85xx/u-boot.lds b/arch/powerpc/cpu/mpc85xx/u-boot.lds
index c88b1f3..85042c5 100644
--- a/arch/powerpc/cpu/mpc85xx/u-boot.lds
+++ b/arch/powerpc/cpu/mpc85xx/u-boot.lds
@@ -25,8 +25,7 @@
 #endif
 
 OUTPUT_ARCH(powerpc)
-/* Do we need any of these for elf?
-   __DYNAMIC = 0;    */
+
 PHDRS
 {
   text PT_LOAD;
@@ -38,42 +37,16 @@ SECTIONS
   /* Read-only sections, merged into text segment: */
   . = + SIZEOF_HEADERS;
   .interp : { *(.interp) }
-  .hash          : { *(.hash)		}
-  .dynsym        : { *(.dynsym)		}
-  .dynstr        : { *(.dynstr)		}
-  .rel.text      : { *(.rel.text)		}
-  .rela.text     : { *(.rela.text)	}
-  .rel.data      : { *(.rel.data)		}
-  .rela.data     : { *(.rela.data)	}
-  .rel.rodata    : { *(.rel.rodata)	}
-  .rela.rodata   : { *(.rela.rodata)	}
-  .rel.got       : { *(.rel.got)		}
-  .rela.got      : { *(.rela.got)		}
-  .rel.ctors     : { *(.rel.ctors)	}
-  .rela.ctors    : { *(.rela.ctors)	}
-  .rel.dtors     : { *(.rel.dtors)	}
-  .rela.dtors    : { *(.rela.dtors)	}
-  .rel.bss       : { *(.rel.bss)		}
-  .rela.bss      : { *(.rela.bss)		}
-  .rel.plt       : { *(.rel.plt)		}
-  .rela.plt      : { *(.rela.plt)		}
-  .init          : { *(.init)	}
-  .plt : { *(.plt) }
   .text      :
   {
-    *(.text)
-    *(.got1)
+    *(.text*)
    } :text
     _etext = .;
     PROVIDE (etext = .);
     .rodata    :
    {
-    *(.eh_frame)
     *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*)))
   } :text
-  .fini      : { *(.fini)    } =0
-  .ctors     : { *(.ctors)   }
-  .dtors     : { *(.dtors)   }
 
   /* Read-write section, merged into data segment: */
   . = (. + 0x00FF) & 0xFFFFFF00;
@@ -81,23 +54,19 @@ SECTIONS
   PROVIDE (erotext = .);
   .reloc   :
   {
-    *(.got)
+    KEEP(*(.got))
     _GOT2_TABLE_ = .;
-    *(.got2)
+    KEEP(*(.got2))
     _FIXUP_TABLE_ = .;
-    *(.fixup)
+    KEEP(*(.fixup))
   }
   __got2_entries = (_FIXUP_TABLE_ - _GOT2_TABLE_) >> 2;
   __fixup_entries = (. - _FIXUP_TABLE_) >> 2;
 
   .data    :
   {
-    *(.data)
-    *(.data1)
-    *(.sdata)
-    *(.sdata2)
-    *(.dynamic)
-    CONSTRUCTORS
+    *(.data*)
+    *(.sdata*)
   }
   _edata  =  .;
   PROVIDE (edata = .);
@@ -126,7 +95,7 @@ SECTIONS
 
   .resetvec RESET_VECTOR_ADDRESS :
   {
-    *(.resetvec)
+    KEEP(*(.resetvec))
   } :text = 0xffff
 
   . = RESET_VECTOR_ADDRESS + 0x4;
@@ -145,9 +114,8 @@ SECTIONS
   __bss_start = .;
   .bss (NOLOAD)       :
   {
-   *(.sbss) *(.scommon)
-   *(.dynbss)
-   *(.bss)
+   *(.sbss*)
+   *(.bss*)
    *(COMMON)
   } :bss
 
-- 
1.7.0.4