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diff gen/main.cpp @ 1052:12ea38902e83

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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.
author Christian Kamm <kamm incasoftware de>
date Sat, 07 Mar 2009 19:38:00 +0100
parents abfe71f5b911
children 7ce8355fbcc6
line wrap: on
line diff
--- 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();