[PECOFF] Do not set the entry address if /noentry option is given.

This is the first step towards DLL creation support. Resource-only DLLs
don't have entry point address.

llvm-svn: 195510

3 files changed, 24 insertions, 1 deletions

diff --git a/lld/lib/Driver/WinLinkDriver.cpp b/lld/lib/Driver/WinLinkDriver.cpp
index 7e9a55cfcbd..7864f034e96 100644
--- a/lld/lib/Driver/WinLinkDriver.cpp
+++ b/lld/lib/Driver/WinLinkDriver.cpp
@@ -891,12 +891,18 @@ WinLinkDriver::parse(int argc, const char *argv[], PECOFFLinkingContext &ctx,
         new PECOFFFileNode(ctx, path)));
 
   // Use the default entry name if /entry option is not given.
-  if (ctx.entrySymbolName().empty())
+  if (ctx.entrySymbolName().empty() && !parsedArgs->getLastArg(OPT_noentry))
     ctx.setEntrySymbolName(getDefaultEntrySymbolName(ctx));
   StringRef entry = ctx.entrySymbolName();
   if (!entry.empty())
     ctx.addInitialUndefinedSymbol(entry);
 
+  // Specify /noentry without /dll is an error.
+  if (parsedArgs->getLastArg(OPT_noentry) && !parsedArgs->getLastArg(OPT_dll)) {
+    diagnostics << "/noentry must be specified with /dll\n";
+    return false;
+  }
+
   // Specifying both /opt:ref and /opt:noref is an error.
   if (parsedArgs->getLastArg(OPT_ref) && parsedArgs->getLastArg(OPT_ref_no)) {
     diagnostics << "/opt:ref must not be specified with /opt:noref\n";
diff --git a/lld/lib/Driver/WinLinkOptions.td b/lld/lib/Driver/WinLinkOptions.td
index 6404680bd62..8e9f5b21d2c 100644
--- a/lld/lib/Driver/WinLinkOptions.td
+++ b/lld/lib/Driver/WinLinkOptions.td
@@ -50,6 +50,8 @@ def incl : Joined<["/", "-"], "include:">,
 def incl_c : Separate<["/", "-"], "include">, Alias<incl>;
 
 def nodefaultlib_all : F<"nodefaultlib">;
+def noentry : F<"noentry">;
+def dll : F<"dll">;
 
 def debug : F<"debug">;
 def swaprun_cd : F<"swaprun:cd">;
diff --git a/lld/unittests/DriverTests/WinLinkDriverTest.cpp b/lld/unittests/DriverTests/WinLinkDriverTest.cpp
index 89a590fbd91..fbe6cdd8498 100644
--- a/lld/unittests/DriverTests/WinLinkDriverTest.cpp
+++ b/lld/unittests/DriverTests/WinLinkDriverTest.cpp
@@ -341,6 +341,21 @@ TEST_F(WinLinkParserTest, DisallowLib) {
 }
 
 //
+// Tests for DLL.
+//
+
+TEST_F(WinLinkParserTest, NoEntry) {
+  EXPECT_TRUE(parse("link.exe", "/noentry", "/dll", "a.obj", nullptr));
+  EXPECT_EQ("", _context.entrySymbolName());
+}
+
+TEST_F(WinLinkParserTest, NoEntryError) {
+  // /noentry without /dll is an error.
+  EXPECT_FALSE(parse("link.exe", "/noentry", "a.obj", nullptr));
+  EXPECT_EQ("/noentry must be specified with /dll\n", errorMessage());
+}
+
+//
 // Tests for boolean flags.
 //