Re: [Qemu-devel] [Bug 1257099] [NEW] QEMU fails to build on CentOS 5.10 with relocation R_X86_64_PC32 error

[Don Slutz <dslutz@verizon.com>]

On 12/05/13 10:18, Paolo Bonzini wrote:
> Il 04/12/2013 02:32, Don Slutz ha scritto:
>> Any hints or pointers about the bug in RHEL5 binutils?  I can try and
>> make a patch to auto detect this.
> Actually it's RHEL5 GCC:
>
> $ cat f.c
> void *
> f(unsigned char *buf, int len)
> {
>      return (void*)0L;
> }
>
>
> void *
> g(unsigned char *buf, int len)
> {
>      return f(buf, len);
> }
> $ gcc -shared -o f.so f.c -fPIE -fPIC
> /usr/bin/ld: /tmp/ccQc9els.o: relocation R_X86_64_PC32 against `f' can not be used when making a shared object; recompile with -fPIC
> /usr/bin/ld: final link failed: Bad value
> collect2: ld returned 1 exit status
>
>
> The bug is simply that "-fPIE -fPIC" counts as -fPIE rather than -fPIC:
>
> $ gcc -S -o - f.c -fPIE |grep call
> 	call	f                      # PC32 relocation
> $ gcc -S -o - f.c -fPIC |grep call
> 	call	f@PLT                  # PLT32 relocation
>
> On RHEL5:
> $ gcc -S -o - f.c -fPIE -fPIC |grep call
> 	call	f
>
> On RHEL6:
> $ gcc -S -o - f.c -fPIE -fPIC |grep call
> 	call	f@PLT
>
> Paolo
How about this as a patch:

 From 282fba086186ff3b8e2b2b15e647df2b58d082dd Mon Sep 17 00:00:00 2001
From: Don Slutz <dslutz@verizon.com>
Date: Thu, 5 Dec 2013 18:50:18 +0000
Subject: [PATCH] configure: Auto disabling of PIE due to broken toolchain
  support (bug #1257099)

See https://bugs.launchpad.net/bugs/1257099

On RHEL5 GCC, you can get 'relocation R_X86_64_PC32' errors from ld.
So disable PIE is this is true.

Signed-off-by: Don Slutz <dslutz@verizon.com>
---
  configure | 43 +++++++++++++++++++++++++++++++++++--------
  1 file changed, 35 insertions(+), 8 deletions(-)

diff --git a/configure b/configure
index cf8123b..a51a9dd 100755
--- a/configure
+++ b/configure
@@ -1339,23 +1339,50 @@ if test "$pie" != "no" ; then
  #  define THREAD
  #endif

+void *f(unsigned char *buf, int len);
+void *g(unsigned char *buf, int len);
+
+void *
+f(unsigned char *buf, int len)
+{
+    return (void*)0L;
+}
+
+
+void *
+g(unsigned char *buf, int len)
+{
+    return f(buf, len);
+}
+
+#ifdef PIE
  static THREAD int tls_var;

  int main(void) { return tls_var; }
+#endif

  EOF
-  if compile_prog "-fPIE -DPIE" "-pie"; then
-    QEMU_CFLAGS="-fPIE -DPIE $QEMU_CFLAGS"
-    LDFLAGS="-pie $LDFLAGS"
-    pie="yes"
-    if compile_prog "" "-Wl,-z,relro -Wl,-z,now" ; then
-      LDFLAGS="-Wl,-z,relro -Wl,-z,now $LDFLAGS"
+  if compile_prog "-shared -fPIE -fPIC" ""; then
+    if compile_prog "-fPIE -DPIE" "-pie"; then
+      QEMU_CFLAGS="-fPIE -DPIE $QEMU_CFLAGS"
+      LDFLAGS="-pie $LDFLAGS"
+      pie="yes"
+      if compile_prog "" "-Wl,-z,relro -Wl,-z,now" ; then
+        LDFLAGS="-Wl,-z,relro -Wl,-z,now $LDFLAGS"
+      fi
+    else
+      if test "$pie" = "yes"; then
+        error_exit "PIE not available due to missing toolchain support"
+      else
+        echo "Disabling PIE due to missing toolchain support"
+        pie="no"
+      fi
      fi
    else
      if test "$pie" = "yes"; then
-      error_exit "PIE not available due to missing toolchain support"
+      error_exit "PIE not available due to broken toolchain support"
      else
-      echo "Disabling PIE due to missing toolchain support"
+      echo "Disabling PIE due to broken toolchain support"
        pie="no"
      fi
    fi
-- 
1.8.2.1