[LTO API] add lto_codegen_set_module to set the destination module.

When debugging LTO issues with ld64, we use -save-temps to save the merged
optimized bitcode file, then invoke ld64 again on the single bitcode file to
speed up debugging code generation passes and ld64 stuff after code generation.

llvm linking a single bitcode file via lto_codegen_add_module will generate a
different bitcode file from the single input. With the newly-added
lto_codegen_set_module, we can make sure the destination module is the same as
the input.

lto_codegen_set_module will transfer the ownship of the module to code
generator.

rdar://19024554

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230290 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm-c/lto.h b/include/llvm-c/lto.h
index 1fe0cd5c75d27d6aee047e4d30b90a6501103e6e..c6acdaddca535e3a1cae32ddd451a3272a3cccc3 100644 (file)
--- a/include/llvm-c/lto.h
+++ b/include/llvm-c/lto.h
@@ -40,7 +40,7 @@ typedef bool lto_bool_t;
  * @{
  */
 
-#define LTO_API_VERSION 12
+#define LTO_API_VERSION 13
 
 /**
  * \since prior to LTO_API_VERSION=3
@@ -395,6 +395,17 @@ lto_codegen_dispose(lto_code_gen_t);
 extern lto_bool_t
 lto_codegen_add_module(lto_code_gen_t cg, lto_module_t mod);
 
+/**
+ * Sets the object module for code generation. This will transfer the ownship of
+ * the module to code generator.
+ *
+ * \c cg and \c mod must both be in the same context.
+ *
+ * \since prior to LTO_API_VERSION=13
+ */
+extern void
+lto_codegen_set_module(lto_code_gen_t cg, lto_module_t mod);
+
 /**
  * Sets if debug info should be generated.
  * Returns true on error (check lto_get_error_message() for details).

diff --git a/include/llvm/LTO/LTOCodeGenerator.h b/include/llvm/LTO/LTOCodeGenerator.h
index ab307bf2d0c33fe89d592559b3e9e100b6ddfb01..cdfc543ec243d96a090afd40c7a92bbbc9fe1fa4 100644 (file)
--- a/include/llvm/LTO/LTOCodeGenerator.h
+++ b/include/llvm/LTO/LTOCodeGenerator.h
@@ -67,6 +67,9 @@ struct LTOCodeGenerator {
   // Merge given module, return true on success.
   bool addModule(struct LTOModule *);
 
+  // Set the destination module.
+  void setModule(struct LTOModule *);
+
   void setTargetOptions(TargetOptions options);
   void setDebugInfo(lto_debug_model);
   void setCodePICModel(lto_codegen_model);

diff --git a/include/llvm/Linker/Linker.h b/include/llvm/Linker/Linker.h
index 9c3ecea590bdc623604595621cdf7474c27833ad..aac9dcdcb36bb6bc932018f33e27d8980404a21d 100644 (file)
--- a/include/llvm/Linker/Linker.h
+++ b/include/llvm/Linker/Linker.h
@@ -70,6 +70,9 @@ public:
   /// Returns true on error.
   bool linkInModule(Module *Src);
 
+  /// \brief Set the composite to the passed-in module.
+  void setModule(Module *Dst);
+
   static bool LinkModules(Module *Dest, Module *Src,
                           DiagnosticHandlerFunction DiagnosticHandler);
 

diff --git a/lib/LTO/LTOCodeGenerator.cpp b/lib/LTO/LTOCodeGenerator.cpp
index 6e5bdaa97c77ddcdc21d27d51d72486ee912a091..1ba4159c9bf14f2eec3686b07d0e1aac35d45f8a 100644 (file)
--- a/lib/LTO/LTOCodeGenerator.cpp
+++ b/lib/LTO/LTOCodeGenerator.cpp
@@ -141,6 +141,22 @@ bool LTOCodeGenerator::addModule(LTOModule *mod) {
   return !ret;
 }
 
+void LTOCodeGenerator::setModule(LTOModule *Mod) {
+  assert(&Mod->getModule().getContext() == &Context &&
+         "Expected module in same context");
+
+  // Delete the old merged module.
+  if (IRLinker.getModule())
+    IRLinker.deleteModule();
+  AsmUndefinedRefs.clear();
+
+  IRLinker.setModule(&Mod->getModule());
+
+  const std::vector<const char*> &Undefs = Mod->getAsmUndefinedRefs();
+  for (int I = 0, E = Undefs.size(); I != E; ++I)
+    AsmUndefinedRefs[Undefs[I]] = 1;
+}
+
 void LTOCodeGenerator::setTargetOptions(TargetOptions options) {
   Options = options;
 }

diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index b55fe483fb2a1dcb69c7c47834d07ceb144c209c..e6d9acc50981372836f2103f3be35dd453caa863 100644 (file)
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -1748,6 +1748,10 @@ bool Linker::linkInModule(Module *Src) {
   return RetCode;
 }
 
+void Linker::setModule(Module *Dst) {
+  init(Dst, DiagnosticHandler);
+}
+
 //===----------------------------------------------------------------------===//
 // LinkModules entrypoint.
 //===----------------------------------------------------------------------===//

diff --git a/test/LTO/X86/set-merged.ll b/test/LTO/X86/set-merged.ll
new file mode 100644 (file)
index 0000000..0e2e1ea
--- /dev/null
+++ b/test/LTO/X86/set-merged.ll
@@ -0,0 +1,36 @@
+; RUN: llvm-as < %s >%t1
+; RUN: llvm-lto -exported-symbol=_main -set-merged-module -o %t2 %t1
+; RUN: llvm-objdump -d %t2 | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.10.0"
+
+; CHECK: _main
+; CHECK: movl $132
+define i32 @_Z3fooi(i32 %a) {
+entry:
+  %a.addr = alloca i32, align 4
+  store i32 %a, i32* %a.addr, align 4
+  %0 = load i32* %a.addr, align 4
+  %1 = load i32* %a.addr, align 4
+  %call = call i32 @_Z4bar2i(i32 %1)
+  %add = add nsw i32 %0, %call
+  ret i32 %add
+}
+
+define i32 @_Z4bar2i(i32 %a) {
+entry:
+  %a.addr = alloca i32, align 4
+  store i32 %a, i32* %a.addr, align 4
+  %0 = load i32* %a.addr, align 4
+  %mul = mul nsw i32 2, %0
+  ret i32 %mul
+}
+
+define i32 @main() {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval
+  %call = call i32 @_Z3fooi(i32 44)
+  ret i32 %call
+}

diff --git a/tools/llvm-lto/llvm-lto.cpp b/tools/llvm-lto/llvm-lto.cpp
index 92bac8351fd791f4939d68ff62e3fa86f66d7368..32b31343411f1074f9a597fb9214abb6c9dcada7 100644 (file)
--- a/tools/llvm-lto/llvm-lto.cpp
+++ b/tools/llvm-lto/llvm-lto.cpp
@@ -69,6 +69,10 @@ static cl::opt<bool> ListSymbolsOnly(
     "list-symbols-only", cl::init(false),
     cl::desc("Instead of running LTO, list the symbols in each IR file"));
 
+static cl::opt<bool> SetMergedModule(
+    "set-merged-module", cl::init(false),
+    cl::desc("Use the first input module as the merged module"));
+
 namespace {
 struct ModuleInfo {
   std::vector<bool> CanBeHidden;
@@ -194,15 +198,22 @@ int main(int argc, char **argv) {
       return 1;
     }
 
-    if (!CodeGen.addModule(Module.get()))
+    LTOModule *LTOMod = Module.get();
+
+    // We use the first input module as the destination module when
+    // SetMergedModule is true.
+    if (SetMergedModule && i == BaseArg) {
+      // Transfer ownership to the code generator.
+      CodeGen.setModule(Module.release());
+    } else if (!CodeGen.addModule(Module.get()))
       return 1;
 
-    unsigned NumSyms = Module->getSymbolCount();
+    unsigned NumSyms = LTOMod->getSymbolCount();
     for (unsigned I = 0; I < NumSyms; ++I) {
-      StringRef Name = Module->getSymbolName(I);
+      StringRef Name = LTOMod->getSymbolName(I);
       if (!DSOSymbolsSet.count(Name))
         continue;
-      lto_symbol_attributes Attrs = Module->getSymbolAttributes(I);
+      lto_symbol_attributes Attrs = LTOMod->getSymbolAttributes(I);
       unsigned Scope = Attrs & LTO_SYMBOL_SCOPE_MASK;
       if (Scope != LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN)
         KeptDSOSyms.push_back(Name);

diff --git a/tools/lto/lto.cpp b/tools/lto/lto.cpp
index 3a336526e6b301babc40e9f31d53b75c2309deef..714b8e02d20dd9bd960e8e6a2534a03923eadbdd 100644 (file)
--- a/tools/lto/lto.cpp
+++ b/tools/lto/lto.cpp
@@ -248,6 +248,10 @@ bool lto_codegen_add_module(lto_code_gen_t cg, lto_module_t mod) {
   return !unwrap(cg)->addModule(unwrap(mod));
 }
 
+void lto_codegen_set_module(lto_code_gen_t cg, lto_module_t mod) {
+  unwrap(cg)->setModule(unwrap(mod));
+}
+
 bool lto_codegen_set_debug_model(lto_code_gen_t cg, lto_debug_model debug) {
   unwrap(cg)->setDebugInfo(debug);
   return false;

diff --git a/tools/lto/lto.exports b/tools/lto/lto.exports
index 9ef60772fb85227973ff5290d15658115bb8c80c..8729050123e690183962ec1a0e09c7af3148417d 100644 (file)
--- a/tools/lto/lto.exports
+++ b/tools/lto/lto.exports
@@ -25,6 +25,7 @@ lto_module_dispose
 lto_api_version
 lto_codegen_set_diagnostic_handler
 lto_codegen_add_module
+lto_codegen_set_module
 lto_codegen_add_must_preserve_symbol
 lto_codegen_compile
 lto_codegen_create