AArch64: Reformat inline-asm in elf_machine_load_address

This patch reformats the inline-asm in elf_machine_load_address so it is
easier to change only part of the inline-asm.  That is using string
concatenating instead of string continuation.

Also document why this inline-asm works - it depends on the 32bit
relocation being resolved at link time.

ChangeLog:

2014-11-21  Will Newton  <will.newton@linaro.org>
	    Andrew Pinski  <andrew.pinski@caviumnetworks.com>

	* sysdeps/aarch64/dl-machine.h (elf_machine_load_address):
	Refactor inline-asm.  Also add comment.

diff --git a/ChangeLog b/ChangeLog
index 3fd08436cb6fa08eaa8aeb21548212f92225b050..076c09df189593d35fb1471e0d61d5d06e126d69 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,9 @@
 2014-11-21  Will Newton  <will.newton@linaro.org>
            Andrew Pinski  <andrew.pinski@caviumnetworks.com>
 
+       * sysdeps/aarch64/dl-machine.h (elf_machine_load_address):
+       Refactor inline-asm.  Also add comment.
+
        * sysdeps/aarch64/bits/link.h (la_aarch64_gnu_pltenter): Use
        ElfW macro instead of hardcoded Elf64 types.
        (la_aarch64_gnu_pltenter): Likewise.

diff --git a/sysdeps/aarch64/dl-machine.h b/sysdeps/aarch64/dl-machine.h
index 7f5ce2b6711caef1222d9a338491e6296d71bd40..1294369268c93cf804b6221c5797ea550d73dd84 100644 (file)
--- a/sysdeps/aarch64/dl-machine.h
+++ b/sysdeps/aarch64/dl-machine.h
@@ -52,19 +52,22 @@ elf_machine_load_address (void)
      The choice of symbol is arbitrary. The static address we obtain
      by constructing a non GOT reference to the symbol, the dynamic
      address of the symbol we compute using adrp/add to compute the
-     symbol's address relative to the PC. */
+     symbol's address relative to the PC.
+     This depends on 32bit relocations being resolved at link time
+     and that the static address fits in the 32bits.  */
 
   ElfW(Addr) static_addr;
   ElfW(Addr) dynamic_addr;
 
-  asm ("                                       \n\
-       adrp    %1, _dl_start;                  \n\
-        add    %1, %1, #:lo12:_dl_start        \n\
-        ldr    %w0, 1f                         \n\
-       b       2f                              \n\
-1:     .word   _dl_start                       \n\
-2:                                             \n\
-       " : "=r" (static_addr),  "=r" (dynamic_addr));
+  asm ("                                       \n"
+"      adrp    %1, _dl_start;                  \n"
+"      add     %1, %1, #:lo12:_dl_start        \n"
+"      ldr     %w0, 1f                         \n"
+"      b       2f                              \n"
+"1:                                            \n"
+"      .word   _dl_start                       \n"
+"2:                                            \n"
+    : "=r" (static_addr),  "=r" (dynamic_addr));
   return dynamic_addr - static_addr;
 }