LOCALMODs from hg 0b098ca44de7 against r158408 (hg 90a87d6bfe45)

(only non-new files; new files in git 4f429c8b)

Change-Id: Ia39f818088485bd90e4d048db404f8d6ba5f836b

2 files changed, 38 insertions, 1 deletions

diff --git a/lib/Linker/LinkArchives.cpp b/lib/Linker/LinkArchives.cpp
index c16d1958cd..c5656a54c9 100644
--- a/lib/Linker/LinkArchives.cpp
+++ b/lib/Linker/LinkArchives.cpp
@@ -16,10 +16,24 @@
 #include "llvm/Module.h"
 #include "llvm/ADT/SetOperations.h"
 #include "llvm/Bitcode/Archive.h"
+
+#include "llvm/Support/CommandLine.h" // @LOCALMOD
+
 #include <memory>
 #include <set>
 using namespace llvm;
 
+// @LOCALMOD-START
+// NOTE: this has a similar effect as
+//        tools/llvm/llvm-preserve.ll
+// which in turn is similar to the GNUS's attribute((used))
+// TODO(robertm): This is a little hackish for now
+static cl::list<std::string>
+UndefList("referenced-list", cl::value_desc("list"),
+          cl::desc("A list of symbols assumed to be referenced externally"),
+          cl::CommaSeparated);
+// @LOCALMOD-END
+  
 /// GetAllUndefinedSymbols - calculates the set of undefined symbols that still
 /// exist in an LLVM module. This is a bit tricky because there may be two
 /// symbols with the same name but different LLVM types that will be resolved to
@@ -36,7 +50,10 @@ static void
 GetAllUndefinedSymbols(Module *M, std::set<std::string> &UndefinedSymbols) {
   std::set<std::string> DefinedSymbols;
   UndefinedSymbols.clear();
-
+  // @LOCALMOD-START
+  UndefinedSymbols.insert(UndefList.begin(), UndefList.end());
+  // @LOCALMOD-END
+  
   // If the program doesn't define a main, try pulling one in from a .a file.
   // This is needed for programs where the main function is defined in an
   // archive, such f2c'd programs.
diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index 7293f3d0e8..aec2547f00 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -932,6 +932,19 @@ void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) {
     ValueMap[I] = DI;
   }
 
+  // @LOCALMOD-BEGIN
+  // Local patch for http://llvm.org/bugs/show_bug.cgi?id=11112
+  // and http://llvm.org/bugs/show_bug.cgi?id=10887
+  // Create an identity mapping for instructions so that alloca instructions
+  // do not get dropped and related debug info isn't lost.  E.g., prevent
+  //   call @llvm.dbg.declare(metadata !{i32 * %local_var}, ...)
+  // from becoming
+  //   call @llvm.dbg.declare(null, ...)
+  for (Function::iterator BB = Src->begin(), BE = Src->end(); BB != BE; ++BB)
+    for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
+      ValueMap[I] = I;
+  // @LOCALMOD-END
+
   if (Mode == Linker::DestroySource) {
     // Splice the body of the source function into the dest function.
     Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList());
@@ -949,6 +962,13 @@ void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) {
     SmallVector<ReturnInst*, 8> Returns; // Ignore returns.
     CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap);
   }
+
+  // @LOCALMOD-BEGIN
+  // There is no need for the identity mapping anymore.
+  for (Function::iterator BB = Src->begin(), BE = Src->end(); BB != BE; ++BB)
+    for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
+      ValueMap.erase(I);
+  // @LOCALMOD-END
   
   // There is no need to map the arguments anymore.
   for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();