From 73a74be705bbcc6c31412acd09306087174b42b5 Mon Sep 17 00:00:00 2001
From: Reid Spencer <rspencer@reidspencer.com>
Date: Wed, 21 Dec 2005 05:03:23 +0000
Subject: [PATCH] Implement PR512: This patch adds a -post-link-opts option to
 llvm-ld which allows an arbitrary program to optimize bytecode after linking.
 The program is passed two file names. The first is the input (linked
 bytecode) the second is where it must place its output (presumably after
 optimizing). If the output file is bytecode, it is used as a substitute for
 the input. This will allow things like poolalloc to be written as a separate
 program instead of a loadable module or built into LLVM.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24893 91177308-0d34-0410-b5e6-96231b3b80d8
---
 tools/llvm-ld/llvm-ld.cpp | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/tools/llvm-ld/llvm-ld.cpp b/tools/llvm-ld/llvm-ld.cpp
index 03f1c45cb4f..0c633d2462d 100644
--- a/tools/llvm-ld/llvm-ld.cpp
+++ b/tools/llvm-ld/llvm-ld.cpp
@@ -76,6 +76,10 @@ static cl::opt<bool>NativeCBE("native-cbe",
 static cl::opt<bool>DisableCompression("disable-compression",cl::init(false),
   cl::desc("Disable writing of compressed bytecode files"));
 
+static cl::list<std::string> PostLinkOpts("post-link-opts",
+  cl::value_desc("path to post-link optimization programs"),
+  cl::desc("Run one or more optimization programs after linking"));
+
 // Compatibility options that are ignored but supported by LD
 static cl::opt<std::string> CO3("soname", cl::Hidden,
   cl::desc("Compatibility option: ignored"));
@@ -450,6 +454,41 @@ int main(int argc, char **argv, char **envp) {
     // If we are not linking a library, generate either a native executable
     // or a JIT shell script, depending upon what the user wants.
     if (!LinkAsLibrary) {
+      // If the user wants to run a post-link optimization, run it now.
+      if (!PostLinkOpts.empty()) {
+        std::vector<std::string> opts = PostLinkOpts;
+        for (std::vector<std::string>::iterator I = opts.begin(),
+             E = opts.end(); I != E; ++I) {
+          sys::Path prog(*I);
+          if (!prog.canExecute()) {
+            prog = sys::Program::FindProgramByName(*I);
+            if (prog.isEmpty())
+              return PrintAndReturn(std::string("Optimization program '") + *I +
+                "' is not found or not executable.");
+          }
+          // Get the program arguments
+          sys::Path tmp_output("opt_result");
+          if (!tmp_output.createTemporaryFileOnDisk()) {
+            return PrintAndReturn(
+              "Can't create temporary file for post-link optimization");
+          }
+          const char* args[4];
+          args[0] = I->c_str();
+          args[1] = RealBytecodeOutput.c_str();
+          args[2] = tmp_output.c_str();
+          args[3] = 0;
+          if (0 == sys::Program::ExecuteAndWait(prog, args)) {
+            if (tmp_output.isBytecodeFile()) {
+              sys::Path target(RealBytecodeOutput);
+              target.eraseFromDisk();
+              tmp_output.renamePathOnDisk(target);
+            } else
+              return PrintAndReturn(
+                "Post-link optimization output is not bytecode");
+          }
+        }
+      }
+
       // If the user wants to generate a native executable, compile it from the
       // bytecode file.
       //