From de7ed84f77d2e27b5fdea1ad0774994df2720caa Mon Sep 17 00:00:00 2001 From: Olly Betts Date: Fri, 21 Feb 2014 08:09:58 +1300 Subject: [PATCH] Recommend compiling with PIC consistently. While shared objects with non-PIC code work on some architectures (notably x86), unless code is always PIC on that arch (not true for x86) doing so requires runtime relocations, which prevents the object actually being shared, and means such segments can't be marked as read-only. --- Doc/Manual/Java.html | 7 +++---- Doc/Manual/Lua.html | 4 ++-- Doc/Manual/Perl5.html | 4 ++-- Doc/Manual/Ruby.html | 20 ++++++++++++++------ Doc/Manual/SWIGPlus.html | 2 +- Doc/Manual/Scripting.html | 7 +------ Doc/Manual/Tcl.html | 12 ++++++------ 7 files changed, 29 insertions(+), 27 deletions(-) diff --git a/Doc/Manual/Java.html b/Doc/Manual/Java.html index 08c80c83a..c1b42f605 100644 --- a/Doc/Manual/Java.html +++ b/Doc/Manual/Java.html @@ -332,8 +332,8 @@ Assuming you have code you need to link to in a file called example.c, 
 $ swig -java example.i
-$ gcc -c example_wrap.c  -I/usr/java/include -I/usr/java/include/solaris
-$ gcc -c example.c
+$ gcc -fPIC -c example_wrap.c -I/usr/java/include -I/usr/java/include/solaris
+$ gcc -fPIC -c example.c
 $ ld -G example_wrap.o example.o -o libexample.so
@@ -493,8 +493,7 @@ compiler. For example: 
 % swig -c++ -java example.i
 % g++ -c -fpic example.cxx
-% g++ -c -fpic example_wrap.cxx -I/usr/java/j2sdk1.4.1/include -I/usr/java/
-j2sdk1.4.1/include/linux
+% g++ -c -fpic example_wrap.cxx -I/usr/java/j2sdk1.4.1/include -I/usr/java/j2sdk1.4.1/include/linux
 % g++ -shared example.o example_wrap.o -o libexample.so
diff --git a/Doc/Manual/Lua.html b/Doc/Manual/Lua.html index 88d26f385..aab6a2ceb 100644 --- a/Doc/Manual/Lua.html +++ b/Doc/Manual/Lua.html @@ -240,8 +240,8 @@ Most, but not all platforms support the dynamic loading of modules (Windows & 

 $ swig -lua example.i -o example_wrap.c
-$ gcc -I/usr/include/lua -c example_wrap.c -o example_wrap.o
-$ gcc -c example.c -o example.o
+$ gcc -fPIC -I/usr/include/lua -c example_wrap.c -o example_wrap.o
+$ gcc -fPIC -c example.c -o example.o
 $ gcc -shared -I/usr/include/lua -L/usr/lib/lua example_wrap.o example.o -o example.so

diff --git a/Doc/Manual/Perl5.html b/Doc/Manual/Perl5.html index db8c0e602..9e577b08b 100644 --- a/Doc/Manual/Perl5.html +++ b/Doc/Manual/Perl5.html @@ -493,8 +493,8 @@ Solaris, you often need to add an extra library -lCrun like this: 

 $ swig -c++ -perl example.i
-$ CC -c example.cxx
-$ CC -c example_wrap.cxx -I/usr/lib/perl/5.14/i386-linux/CORE
+$ CC -Kpic -c example.cxx
+$ CC -Kpic -c example_wrap.cxx -I/usr/lib/perl/5.14/i386-linux/CORE
 $ CC -shared example.o example_wrap.o -o example.so -lCrun
diff --git a/Doc/Manual/Ruby.html b/Doc/Manual/Ruby.html index 301631a20..6ff98ca23 100644 --- a/Doc/Manual/Ruby.html +++ b/Doc/Manual/Ruby.html @@ -259,14 +259,22 @@ operating system would look something like this: 

$ swig -ruby example.i
-$ gcc -c example.c
-$ gcc -c example_wrap.c -I/usr/local/lib/ruby/1.6/i686-linux
+$ gcc -O2 -fPIC -c example.c
+$ gcc -O2 -fPIC -c example_wrap.c -I/usr/local/lib/ruby/1.6/i686-linux
 $ gcc -shared example.o example_wrap.o -o example.so
-

For other platforms it may be necessary to compile with the -fPIC -option to generate position-independent code. If in doubt, consult the +

+The -fPIC option tells GCC to generate position-independent code (PIC) +which is required for most architectures (it's not vital on x86, but +still a good idea as it allows code pages from the library to be shared between +processes). Other compilers may need a different option specified instead of +-fPIC. +

+ +

+If in doubt, consult the manual pages for your compiler and linker to determine the correct set of options. You might also check the SWIG Wiki for additional information.

@@ -325,8 +333,8 @@ using the C++ compiler. For example: 

 $ swig -c++ -ruby example.i
-$ g++ -c example.cxx
-$ g++ -c example_wrap.cxx -I/usr/local/lib/ruby/1.6/i686-linux
+$ g++ -fPIC -c example.cxx
+$ g++ -fPIC -c example_wrap.cxx -I/usr/local/lib/ruby/1.6/i686-linux
 $ g++ -shared example.o example_wrap.o -o example.so
diff --git a/Doc/Manual/SWIGPlus.html b/Doc/Manual/SWIGPlus.html index e0e7dbcaf..aa02b2dee 100644 --- a/Doc/Manual/SWIGPlus.html +++ b/Doc/Manual/SWIGPlus.html @@ -216,7 +216,7 @@ to use the C++ compiler. For example: 
 $ swig -c++ -tcl example.i
-$ c++ -c example_wrap.cxx 
+$ c++ -fPIC -c example_wrap.cxx 
 $ c++ example_wrap.o $(OBJS) -o example.so
diff --git a/Doc/Manual/Scripting.html b/Doc/Manual/Scripting.html index 26a8dd017..c714fa0d7 100644 --- a/Doc/Manual/Scripting.html +++ b/Doc/Manual/Scripting.html @@ -368,17 +368,12 @@ for a few common platforms is shown below:

 # Build a shared library for Solaris
-gcc -c example.c example_wrap.c -I/usr/local/include
+gcc -fpic -c example.c example_wrap.c -I/usr/local/include
 ld -G example.o example_wrap.o -o example.so
 
 # Build a shared library for Linux
 gcc -fpic -c example.c example_wrap.c -I/usr/local/include
 gcc -shared example.o example_wrap.o -o example.so
-
-# Build a shared library for Irix
-gcc -c example.c example_wrap.c -I/usr/local/include
-ld -shared example.o example_wrap.o -o example.so
-

diff --git a/Doc/Manual/Tcl.html b/Doc/Manual/Tcl.html index e6b3b4a43..9b9cd7218 100644 --- a/Doc/Manual/Tcl.html +++ b/Doc/Manual/Tcl.html @@ -139,8 +139,8 @@ using commands like this (shown for Linux): 

 $ swig -tcl example.i
-$ gcc -c example.c
-$ gcc -c example_wrap.c -I/usr/local/include
+$ gcc -fPIC -c example.c
+$ gcc -fPIC -c example_wrap.c -I/usr/local/include
 $ gcc -shared example.o example_wrap.o -o example.so
@@ -374,8 +374,8 @@ compiler. For example: 
 % swig -c++ -tcl example.i
-% g++ -c example.cxx
-% g++ -c example_wrap.cxx -I/usr/local/include
+% g++ -fPIC -c example.cxx
+% g++ -fPIC -c example_wrap.cxx -I/usr/local/include
 % g++ -shared example.o example_wrap.o -o example.so
@@ -387,8 +387,8 @@ Solaris, you often need to add an extra library -lCrun like this: 
 % swig -c++ -tcl example.i
-% CC -c example.cxx
-% CC -c example_wrap.cxx -I/usr/local/include
+% CC -KPIC -c example.cxx
+% CC -KPIC -c example_wrap.cxx -I/usr/local/include
 % CC -G example.o example_wrap.o -L/opt/SUNWspro/lib -o example.so -lCrun