# HG changeset patch
# User Christian Kamm <kamm incasoftware de>
# Date 1236451080 -3600
# Node ID 12ea38902e83ef240c71043b1c224e6016577474
# Parent  dc608dc330812b91f0eecba5bb81d696b8410c24
Add '-singleobj' command line switch that will tell LDC to link LLVM modules internally and only emit a single object file.

The switch allows the optimizer and inliner to run on all modules at once and opens the door for template instantiation improvements that should lower compile time and executable size.

diff -r dc608dc33081 -r 12ea38902e83 dmd/module.h
--- a/dmd/module.h	Sat Mar 07 14:25:30 2009 +0100
+++ b/dmd/module.h	Sat Mar 07 19:38:00 2009 +0100
@@ -30,6 +30,7 @@
 #if IN_LLVM
 struct DValue;
 typedef DValue elem;
+namespace llvm { class Module; }
 #else
 #ifdef IN_GCC
 union tree_node; typedef union tree_node elem;
@@ -133,7 +134,6 @@
 #ifdef _DH
     void genhdrfile();  // generate D import file
 #endif
-    void genobjfile(int multiobj);
 //    void gensymfile();
     void gendocfile();
     int needModuleInfo();
@@ -171,6 +171,7 @@
     void genmoduleinfo();
 
     // LDC
+    llvm::Module* genLLVMModule(int multiobj);
     void buildTargetFiles();
     File* buildFilePath(char* forcename, char* path, char* ext);
     Module *isModule() { return this; }
diff -r dc608dc33081 -r 12ea38902e83 gen/main.cpp
--- a/gen/main.cpp	Sat Mar 07 14:25:30 2009 +0100
+++ b/gen/main.cpp	Sat Mar 07 19:38:00 2009 +0100
@@ -4,6 +4,7 @@
 // which uses the llvm license
 
 #include "gen/llvm.h"
+#include "llvm/Linker.h"
 #include "llvm/Target/SubtargetFeature.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetMachineRegistry.h"
@@ -32,6 +33,7 @@
 #include "gen/logger.h"
 #include "gen/linker.h"
 #include "gen/irstate.h"
+#include "gen/toobj.h"
 
 #include "gen/cl_options.h"
 #include "gen/cl_helpers.h"
@@ -41,6 +43,10 @@
 extern void backend_init();
 extern void backend_term();
 
+static cl::opt<bool> singleObj("singleobj",
+    cl::desc("Create only a single output object file"),
+    cl::ZeroOrMore);
+
 static cl::opt<bool> noDefaultLib("nodefaultlib",
     cl::desc("Don't add a default library for linking implicitly"),
     cl::ZeroOrMore);
@@ -796,6 +802,9 @@
     if (global.errors)
         fatal();
 
+    // collects llvm modules to be linked if singleobj is passed
+    std::vector<llvm::Module*> llvmModules;
+
     // Generate output files
     for (int i = 0; i < modules.dim; i++)
     {
@@ -804,8 +813,16 @@
             printf("code      %s\n", m->toChars());
         if (global.params.obj)
         {
-            m->genobjfile(0);
-            global.params.objfiles->push(m->objfile->name->str);
+            llvm::Module* lm = m->genLLVMModule(0);
+            if (!singleObj)
+            {
+                m->deleteObjFile();
+                writeModule(lm, m->objfile->name->str);
+                global.params.objfiles->push(m->objfile->name->str);
+                delete lm;
+            }
+            else
+                llvmModules.push_back(lm);
         }
         if (global.errors)
             m->deleteObjFile();
@@ -815,7 +832,34 @@
             m->gendocfile();
         }
     }
-
+    
+    // internal linking for singleobj
+    if (singleObj && llvmModules.size() > 0)
+    {
+        Module* m = (Module*)modules.data[0];
+        char* name = m->toChars();
+        char* filename = m->objfile->name->str;
+        
+        llvm::Linker linker(name, name);
+        std::string errormsg;
+        for (int i = 0; i < llvmModules.size(); i++)
+        {
+            if(linker.LinkInModule(llvmModules[i], &errormsg))
+                error(errormsg.c_str());
+            delete llvmModules[i];
+        }
+        
+        // workaround for llvm::Linker bug, see llvm #3749
+        llvm::GlobalVariable* ctors = linker.getModule()->getGlobalVariable("llvm.global_ctors");
+        if (ctors)
+            while (ctors->getNumUses() > 0)
+                delete *ctors->use_begin();
+        
+        m->deleteObjFile();
+        writeModule(linker.getModule(), filename);
+        global.params.objfiles->push(filename);
+    }
+    
     backend_term();
     if (global.errors)
         fatal();
diff -r dc608dc33081 -r 12ea38902e83 gen/toobj.cpp
--- a/gen/toobj.cpp	Sat Mar 07 14:25:30 2009 +0100
+++ b/gen/toobj.cpp	Sat Mar 07 19:38:00 2009 +0100
@@ -70,7 +70,7 @@
 
 //////////////////////////////////////////////////////////////////////////////////////////
 
-void Module::genobjfile(int multiobj)
+llvm::Module* Module::genLLVMModule(int multiobj)
 {
     bool logenabled = Logger::enabled();
     if (llvmForceLogging && !logenabled)
@@ -85,9 +85,6 @@
 
     assert(!global.errors);
 
-    // start by deleting the old object file
-    deleteObjFile();
-
     // name the module
     std::string mname(toChars());
     if (md != 0)
@@ -174,17 +171,29 @@
         }
     }
 
+    gIR = NULL;
+    
+    if (llvmForceLogging && !logenabled)
+    {
+        Logger::disable();
+    }
+    
+    return ir.module;
+}
+
+void writeModule(llvm::Module* m, std::string filename)
+{
     // run optimizer
-    ldc_optimize_module(ir.module, global.params.optimizeLevel, global.params.llvmInline);
+    ldc_optimize_module(m, global.params.optimizeLevel, global.params.llvmInline);
 
     // verify the llvm
     if (!noVerify && (global.params.optimizeLevel >= 0 || global.params.llvmInline)) {
         std::string verifyErr;
         Logger::println("Verifying module... again...");
         LOG_SCOPE;
-        if (llvm::verifyModule(*ir.module,llvm::ReturnStatusAction,&verifyErr))
+        if (llvm::verifyModule(*m,llvm::ReturnStatusAction,&verifyErr))
         {
-            error("%s", verifyErr.c_str());
+            //error("%s", verifyErr.c_str());
             fatal();
         }
         else {
@@ -197,27 +206,27 @@
 
     // write LLVM bitcode
     if (global.params.output_bc) {
-        LLPath bcpath = LLPath(objfile->name->toChars());
+        LLPath bcpath = LLPath(filename);
         bcpath.eraseSuffix();
         bcpath.appendSuffix(std::string(global.bc_ext));
         Logger::println("Writing LLVM bitcode to: %s\n", bcpath.c_str());
         std::ofstream bos(bcpath.c_str(), std::ios::binary);
-        llvm::WriteBitcodeToFile(ir.module, bos);
+        llvm::WriteBitcodeToFile(m, bos);
     }
 
     // write LLVM IR
     if (global.params.output_ll) {
-        LLPath llpath = LLPath(objfile->name->toChars());
+        LLPath llpath = LLPath(filename);
         llpath.eraseSuffix();
         llpath.appendSuffix(std::string(global.ll_ext));
         Logger::println("Writing LLVM asm to: %s\n", llpath.c_str());
         std::ofstream aos(llpath.c_str());
-        ir.module->print(aos, NULL);
+        m->print(aos, NULL);
     }
 
     // write native assembly
     if (global.params.output_s || global.params.output_o) {
-        LLPath spath = LLPath(objfile->name->toChars());
+        LLPath spath = LLPath(filename);
         spath.eraseSuffix();
         spath.appendSuffix(std::string(global.s_ext));
         if (!global.params.output_s) {
@@ -227,12 +236,12 @@
         std::string err;
         {
             llvm::raw_fd_ostream out(spath.c_str(), false, err);
-            write_asm_to_file(*gTargetMachine, *ir.module, out);
+            write_asm_to_file(*gTargetMachine, *m, out);
         }
 
         // call gcc to convert assembly to object file
         if (global.params.output_o) {
-            LLPath objpath = LLPath(objfile->name->toChars());
+            LLPath objpath = LLPath(filename);
             assemble(spath, objpath);
         }
 
@@ -240,14 +249,6 @@
             spath.eraseFromDisk();
         }
     }
-
-    delete ir.module;
-    gIR = NULL;
-    
-    if (llvmForceLogging && !logenabled)
-    {
-        Logger::disable();
-    }
 }
 
 /* ================================================================== */
diff -r dc608dc33081 -r 12ea38902e83 gen/toobj.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gen/toobj.h	Sat Mar 07 19:38:00 2009 +0100
@@ -0,0 +1,6 @@
+#ifndef LDC_GEN_TOOBJ_H
+#define LDC_GEN_TOOBJ_H
+
+void writeModule(llvm::Module* m, std::string filename);
+
+#endif