[llvm-commits] [dragonegg] r100182 - /dragonegg/trunk/www/index.html

[Duncan Sands]

Author: baldrick
Date: Fri Apr  2 03:44:52 2010
New Revision: 100182

URL: http://llvm.org/viewvc/llvm-project?rev=100182&view=rev
Log:
Explain more about getting LLVM IR output.

Modified:
    dragonegg/trunk/www/index.html

Modified: dragonegg/trunk/www/index.html
URL: http://llvm.org/viewvc/llvm-project/dragonegg/trunk/www/index.html?rev=100182&r1=100181&r2=100182&view=diff
==============================================================================
--- dragonegg/trunk/www/index.html (original)
+++ dragonegg/trunk/www/index.html Fri Apr  2 03:44:52 2010
@@ -67,7 +67,7 @@
   <h2>DragonEgg in action</h2>
   <!--=====================================================================-->
 
-  <p>Here is the result of compiling a simple "hello world" program with gcc-4.5.</p>
+  <p>Here is the result of compiling a simple "hello world" program with gcc-4.5:</p>
   <pre>
 $ gcc hello.c -S -O1 -o -
 	.file	"hello.c"
@@ -90,7 +90,7 @@
   </pre>
 
   <p>Adding <tt>-fplugin=path/dragonegg.so</tt> to the gcc command line causes
-  the program to be optimized and codegened by LLVM instead.</p>
+  the program to be optimized and codegened by LLVM instead:</p>
   <pre>
 $ gcc hello.c -S -O1 -o - -fplugin=./dragonegg.so
 	.file	"hello.c"
@@ -120,7 +120,10 @@
 	.section	.note.GNU-stack,"", at progbits
   </pre>
 
-  <p>Adding <tt>-fplugin-arg-dragonegg-emit-ir</tt> causes LLVM IR to be output.</p>
+  <p>Adding <tt>-fplugin-arg-dragonegg-emit-ir</tt> or <tt>-flto</tt> causes
+     LLVM IR to be output (you need to request assembler output, -S, rather
+     than object code output, -c, since otherwise gcc will pass the LLVM IR
+     to the system assembler, which will doubtless fail to assemble it):</p>
   <pre>
 $ gcc hello.c -S -O1 -o - -fplugin=./dragonegg.so -fplugin-arg-dragonegg-emit-ir
 ; ModuleID = 'hello.c'