yaml2obj: add -format=<fmt> to choose input YAML interpretation

See the comment in yaml2obj.cpp for why this is currently needed.
Eventually we can get rid of this, but for now it is needed in order to
make forward progress with adding ELF support, and should be
straightforward to remove later.

Also, preserve the default of COFF, to avoid breaking existing tests.
This policy can easily be changed later though.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183332 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 39 insertions, 11 deletions

diff --git a/tools/yaml2obj/yaml2obj.cpp b/tools/yaml2obj/yaml2obj.cpp
index ac3e4ca..d042d7d 100644
--- a/tools/yaml2obj/yaml2obj.cpp
+++ b/tools/yaml2obj/yaml2obj.cpp
@@ -36,6 +36,25 @@ using namespace llvm;
 static cl::opt<std::string>
   Input(cl::Positional, cl::desc("<input>"), cl::init("-"));
 
+// TODO: The "right" way to tell what kind of object file a given YAML file
+// corresponds to is to look at YAML "tags" (e.g. `!Foo`). Then, different
+// tags (`!ELF`, `!COFF`, etc.) would be used to discriminate between them.
+// Interpreting the tags is needed eventually for when writing test cases,
+// so that we can e.g. have `!Archive` contain a sequence of `!ELF`, and
+// just Do The Right Thing. However, interpreting these tags and acting on
+// them appropriately requires some work in the YAML parser and the YAMLIO
+// library.
+enum YAMLObjectFormat {
+  YOF_COFF
+};
+
+cl::opt<YAMLObjectFormat> Format(
+  "format",
+  cl::desc("Interpret input as this type of object file"),
+  cl::values(
+    clEnumValN(YOF_COFF, "coff", "COFF object file format"),
+  clEnumValEnd));
+
 /// This parses a yaml stream that represents a COFF object file.
 /// See docs/yaml2obj for the yaml scheema.
 struct COFFParser {
@@ -289,16 +308,7 @@ bool writeCOFF(COFFParser &CP, raw_ostream &OS) {
   return true;
 }
 
-int main(int argc, char **argv) {
-  cl::ParseCommandLineOptions(argc, argv);
-  sys::PrintStackTraceOnErrorSignal();
-  PrettyStackTraceProgram X(argc, argv);
-  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
-
-  OwningPtr<MemoryBuffer> Buf;
-  if (MemoryBuffer::getFileOrSTDIN(Input, Buf))
-    return 1;
-
+static int yaml2coff(llvm::raw_ostream &Out, llvm::MemoryBuffer *Buf) {
   yaml::Input YIn(Buf->getBuffer());
   COFFYAML::Object Doc;
   YIn >> Doc;
@@ -317,8 +327,26 @@ int main(int argc, char **argv) {
     errs() << "yaml2obj: Failed to layout COFF file!\n";
     return 1;
   }
-  if (!writeCOFF(CP, outs())) {
+  if (!writeCOFF(CP, Out)) {
     errs() << "yaml2obj: Failed to write COFF file!\n";
     return 1;
   }
+  return 0;
+}
+
+int main(int argc, char **argv) {
+  cl::ParseCommandLineOptions(argc, argv);
+  sys::PrintStackTraceOnErrorSignal();
+  PrettyStackTraceProgram X(argc, argv);
+  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
+
+  OwningPtr<MemoryBuffer> Buf;
+  if (MemoryBuffer::getFileOrSTDIN(Input, Buf))
+    return 1;
+  if (Format == YOF_COFF) {
+    return yaml2coff(outs(), Buf.get());
+  } else {
+    errs() << "Not yet implemented\n";
+    return 1;
+  }
 }