[ModuleUtils] Move EmbedBufferInModule to LLVMTransformsUtils

D116542 adds EmbedBufferInModule which introduces a layer violation
(https://llvm.org/docs/CodingStandards.html#library-layering).
See 2d5f857 for detail.

EmbedBufferInModule does not use BitcodeWriter functionality and should be moved
LLVMTransformsUtils. While here, change the function case to the prevailing
convention.

It seems that EmbedBufferInModule just follows the steps of
EmbedBitcodeInModule. EmbedBitcodeInModule calls WriteBitcodeToFile but has IR
update operations which ideally should be refactored to another library.

Reviewed By: jhuber6

Differential Revision: https://reviews.llvm.org/D118666

clang/lib/CodeGen/BackendUtil.cpp

@@ -84,6 +84,7 @@
 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
 #include "llvm/Transforms/Utils/Debugify.h"
 #include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
 #include "llvm/Transforms/Utils/SymbolRewriter.h"
 #include <memory>
@@ -1775,6 +1776,6 @@ void clang::EmbedObject(llvm::Module *M, const CodeGenOptions &CGOpts,
 
     SmallString<128> SectionName(
         {".llvm.offloading.", std::get<1>(FilenameAndSection)});
-    llvm::EmbedBufferInModule(*M, **ObjectOrErr, SectionName);
+    llvm::embedBufferInModule(*M, **ObjectOrErr, SectionName);
   }
 }

llvm/include/llvm/Bitcode/BitcodeWriter.h

@@ -165,11 +165,6 @@ class raw_ostream;
                             bool EmbedCmdline,
                             const std::vector<uint8_t> &CmdArgs);
 
-  /// Embeds the memory buffer \p Buf into the module \p M as a global using the
-  /// section name \p SectionName.
-  void EmbedBufferInModule(Module &M, MemoryBufferRef Buf,
-                           StringRef SectionName);
-
 } // end namespace llvm
 
 #endif // LLVM_BITCODE_BITCODEWRITER_H

llvm/include/llvm/Transforms/Utils/ModuleUtils.h

@@ -15,6 +15,7 @@
 
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/MemoryBuffer.h"
 #include <utility> // for std::pair
 
 namespace llvm {
@@ -106,6 +107,10 @@ void filterDeadComdatFunctions(
 /// unique identifier for this module, so we return the empty string.
 std::string getUniqueModuleId(Module *M);
 
+/// Embed the memory buffer \p Buf into the module \p M as a global using the
+/// specified section name.
+void embedBufferInModule(Module &M, MemoryBufferRef Buf, StringRef SectionName);
+
 class CallInst;
 namespace VFABI {
 /// Overwrite the Vector Function ABI variants attribute with the names provide

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

@@ -4973,52 +4973,3 @@ void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
   NewUsed->setSection("llvm.metadata");
 }
-
-static void appendToCompilerUsed(Module &M, ArrayRef<GlobalValue *> Values) {
-  GlobalVariable *GV = M.getGlobalVariable("llvm.compiler.used");
-  SmallPtrSet<Constant *, 16> InitAsSet;
-  SmallVector<Constant *, 16> Init;
-  if (GV) {
-    if (GV->hasInitializer()) {
-      auto *CA = cast<ConstantArray>(GV->getInitializer());
-      for (auto &Op : CA->operands()) {
-        Constant *C = cast_or_null<Constant>(Op);
-        if (InitAsSet.insert(C).second)
-          Init.push_back(C);
-      }
-    }
-    GV->eraseFromParent();
-  }
-
-  Type *Int8PtrTy = llvm::Type::getInt8PtrTy(M.getContext());
-  for (auto *V : Values) {
-    Constant *C = ConstantExpr::getPointerBitCastOrAddrSpaceCast(V, Int8PtrTy);
-    if (InitAsSet.insert(C).second)
-      Init.push_back(C);
-  }
-
-  if (Init.empty())
-    return;
-
-  ArrayType *ATy = ArrayType::get(Int8PtrTy, Init.size());
-  GV = new llvm::GlobalVariable(M, ATy, false, GlobalValue::AppendingLinkage,
-                                ConstantArray::get(ATy, Init),
-                                "llvm.compiler.used");
-  GV->setSection("llvm.metadata");
-}
-
-void llvm::EmbedBufferInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
-                               StringRef SectionName) {
-  ArrayRef<char> ModuleData =
-      ArrayRef<char>(Buf.getBufferStart(), Buf.getBufferSize());
-
-  // Embed the buffer into the module.
-  llvm::Constant *ModuleConstant =
-      llvm::ConstantDataArray::get(M.getContext(), ModuleData);
-  llvm::GlobalVariable *GV = new llvm::GlobalVariable(
-      M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
-      ModuleConstant, "llvm.embedded.object");
-  GV->setSection(SectionName);
-
-  appendToCompilerUsed(M, GV);
-}

llvm/lib/Transforms/Utils/ModuleUtils.cpp

@@ -264,3 +264,16 @@ void VFABI::setVectorVariantNames(
   CI->addFnAttr(
       Attribute::get(M->getContext(), MappingsAttrName, Buffer.str()));
 }
+
+void llvm::embedBufferInModule(Module &M, MemoryBufferRef Buf,
+                               StringRef SectionName) {
+  // Embed the buffer into the module.
+  Constant *ModuleConstant = ConstantDataArray::get(
+      M.getContext(), makeArrayRef(Buf.getBufferStart(), Buf.getBufferSize()));
+  GlobalVariable *GV = new GlobalVariable(
+      M, ModuleConstant->getType(), true, GlobalValue::PrivateLinkage,
+      ModuleConstant, "llvm.embedded.object");
+  GV->setSection(SectionName);
+
+  appendToCompilerUsed(M, GV);
+}

utils/bazel/llvm-project-overlay/llvm/BUILD.bazel

@@ -904,7 +904,6 @@ cc_library(
         "include/llvm/Bitcode/BitcodeWriter.h",
         "include/llvm/Bitcode/BitcodeWriterPass.h",
         "include/llvm/Bitcode/LLVMBitCodes.h",
-        "include/llvm/Transforms/Utils/ModuleUtils.h",
     ],
     copts = llvm_copts,
     deps = [