[PATCH] OvmfPkg/QemuKernelLoaderFsDxe: drop tentative const object definition

["Ard Biesheuvel" <ard.biesheuvel@linaro.org>]

Bob reports that VS2017 chokes on a tentative definition of the const
object 'mEfiFileProtocolTemplate', with the following error:

  OvmfPkg\QemuKernelLoaderFsDxe\QemuKernelLoaderFsDxe.c(130):
      error C2220: warning treated as error - no 'object' file generated
  OvmfPkg\QemuKernelLoaderFsDxe\QemuKernelLoaderFsDxe.c(130):
      warning C4132: 'mEfiFileProtocolTemplate': const object should be initialized

Let's turn the only function that relies on this tentative definition
into a forward declaration itself, and move its definition after the
normal definition of the object. That allows us to drop the tentative
definition of the const object, and hopefully make VS2017 happy.

Cc: "Feng, Bob C" <bob.c.feng@intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c | 134 ++++++++++----------
 1 file changed, 70 insertions(+), 64 deletions(-)

diff --git a/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c b/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
index 869549f164f0..fbcdf019bf56 100644
--- a/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
+++ b/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
@@ -123,13 +123,6 @@ typedef struct {
 #define STUB_FILE_FROM_FILE(FilePointer) \
         CR (FilePointer, STUB_FILE, File, STUB_FILE_SIG)
 
-//
-// Tentative definition of the file protocol template. The initializer
-// (external definition) will be provided later.
-//
-STATIC CONST EFI_FILE_PROTOCOL mEfiFileProtocolTemplate;
-
-
 //
 // Protocol member functions for File.
 //
@@ -181,65 +174,10 @@ StubFileOpen (
   IN CHAR16             *FileName,
   IN UINT64             OpenMode,
   IN UINT64             Attributes
-  )
-{
-  CONST STUB_FILE *StubFile;
-  UINTN           BlobType;
-  STUB_FILE       *NewStubFile;
-
+  );
   //
-  // We're read-only.
+  // Forward declaration.
   //
-  switch (OpenMode) {
-    case EFI_FILE_MODE_READ:
-      break;
-
-    case EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE:
-    case EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE | EFI_FILE_MODE_CREATE:
-      return EFI_WRITE_PROTECTED;
-
-    default:
-      return EFI_INVALID_PARAMETER;
-  }
-
-  //
-  // Only the root directory supports opening files in it.
-  //
-  StubFile = STUB_FILE_FROM_FILE (This);
-  if (StubFile->BlobType != KernelBlobTypeMax) {
-    return EFI_UNSUPPORTED;
-  }
-
-  //
-  // Locate the file.
-  //
-  for (BlobType = 0; BlobType < KernelBlobTypeMax; ++BlobType) {
-    if (StrCmp (FileName, mKernelBlob[BlobType].Name) == 0) {
-      break;
-    }
-  }
-  if (BlobType == KernelBlobTypeMax) {
-    return EFI_NOT_FOUND;
-  }
-
-  //
-  // Found it.
-  //
-  NewStubFile = AllocatePool (sizeof *NewStubFile);
-  if (NewStubFile == NULL) {
-    return EFI_OUT_OF_RESOURCES;
-  }
-
-  NewStubFile->Signature = STUB_FILE_SIG;
-  NewStubFile->BlobType  = (KERNEL_BLOB_TYPE)BlobType;
-  NewStubFile->Position  = 0;
-  CopyMem (&NewStubFile->File, &mEfiFileProtocolTemplate,
-    sizeof mEfiFileProtocolTemplate);
-  *NewHandle = &NewStubFile->File;
-
-  return EFI_SUCCESS;
-}
-
 
 /**
   Closes a specified file handle.
@@ -797,6 +735,74 @@ STATIC CONST EFI_FILE_PROTOCOL mEfiFileProtocolTemplate = {
   NULL                        // FlushEx, revision 2
 };
 
+STATIC
+EFI_STATUS
+EFIAPI
+StubFileOpen (
+  IN EFI_FILE_PROTOCOL  *This,
+  OUT EFI_FILE_PROTOCOL **NewHandle,
+  IN CHAR16             *FileName,
+  IN UINT64             OpenMode,
+  IN UINT64             Attributes
+  )
+{
+  CONST STUB_FILE *StubFile;
+  UINTN           BlobType;
+  STUB_FILE       *NewStubFile;
+
+  //
+  // We're read-only.
+  //
+  switch (OpenMode) {
+    case EFI_FILE_MODE_READ:
+      break;
+
+    case EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE:
+    case EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE | EFI_FILE_MODE_CREATE:
+      return EFI_WRITE_PROTECTED;
+
+    default:
+      return EFI_INVALID_PARAMETER;
+  }
+
+  //
+  // Only the root directory supports opening files in it.
+  //
+  StubFile = STUB_FILE_FROM_FILE (This);
+  if (StubFile->BlobType != KernelBlobTypeMax) {
+    return EFI_UNSUPPORTED;
+  }
+
+  //
+  // Locate the file.
+  //
+  for (BlobType = 0; BlobType < KernelBlobTypeMax; ++BlobType) {
+    if (StrCmp (FileName, mKernelBlob[BlobType].Name) == 0) {
+      break;
+    }
+  }
+  if (BlobType == KernelBlobTypeMax) {
+    return EFI_NOT_FOUND;
+  }
+
+  //
+  // Found it.
+  //
+  NewStubFile = AllocatePool (sizeof *NewStubFile);
+  if (NewStubFile == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  NewStubFile->Signature = STUB_FILE_SIG;
+  NewStubFile->BlobType  = (KERNEL_BLOB_TYPE)BlobType;
+  NewStubFile->Position  = 0;
+  CopyMem (&NewStubFile->File, &mEfiFileProtocolTemplate,
+    sizeof mEfiFileProtocolTemplate);
+  *NewHandle = &NewStubFile->File;
+
+  return EFI_SUCCESS;
+}
+
 
 //
 // Protocol member functions for SimpleFileSystem.
-- 
2.17.1