Make building dll less a hack on Windows

Add .dll as a shared library type like .so

If we have target:
cc_binary(
  name = "bar.dll",
  srcs = ["bar.cc"],
  linkshared = 1,
)
Now we can build a dll using bazel build //foo:bar.dll

If the target name is still bar.so, the wrapper script also
build the dll by copying the output file to bar.dll.

--
Change-Id: Ie3d1fb83965ddf691d0cc4734a61a0b0ce89d948
Reviewed-on: https://bazel-review.googlesource.com/#/c/3931
MOS_MIGRATED_REVID=126301390

2 files changed, 6 insertions, 4 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java
index c31f6ab688..061e6fea73 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java
@@ -185,9 +185,11 @@ public abstract class CcBinary implements RuleConfiguredTargetFactory {
     // if cc_binary includes "linkshared=1", then gcc will be invoked with
     // linkopt "-shared", which causes the result of linking to be a shared
     // library. In this case, the name of the executable target should end
-    // in ".so".
-    PathFragment binaryPath =
-        new PathFragment(ruleContext.getTarget().getName() + OsUtils.executableExtension());
+    // in ".so" or "dylib" or ".dll".
+    PathFragment binaryPath = new PathFragment(ruleContext.getTarget().getName());
+    if (!isLinkShared(ruleContext)) {
+      binaryPath = new PathFragment(binaryPath.getPathString() + OsUtils.executableExtension());
+    }
     Artifact binary = ruleContext.getPackageRelativeArtifact(
         binaryPath, ruleContext.getConfiguration().getBinDirectory());
     CppLinkAction.Builder linkActionBuilder =
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppFileTypes.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppFileTypes.java
index c3bd853ff6..ef6e7a1570 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppFileTypes.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppFileTypes.java
@@ -116,7 +116,7 @@ public final class CppFileTypes {
     };
 
 
-  public static final FileType SHARED_LIBRARY = FileType.of(".so", ".dylib");
+  public static final FileType SHARED_LIBRARY = FileType.of(".so", ".dylib", ".dll");
   public static final FileType INTERFACE_SHARED_LIBRARY = FileType.of(".ifso");
   public static final FileType LINKER_SCRIPT = FileType.of(".ld", ".lds", ".ldscript");
   // Matches shared libraries with version names in the extension, i.e.