cmDepends: merge dependers of depend makefile

Since one depender has multiple dependees, depend makefile generated
same depender line by line, to reduce file size and refine make file
parse speed, merge same dependers to one. And add a testcase for
large depend.make which generated source file includes 20000 header
files and run build and incremental build

Signed-off-by: Wangkai <wangkai86@huawei.com>
Signed-off-by: Zhaoyingdong <zhaoyingdong@huawei.com>

1 files changed, 22 insertions, 7 deletions

diff --git a/Source/cmDependsFortran.cxx b/Source/cmDependsFortran.cxx
index a239418fd0..1a06f31706 100644
--- a/Source/cmDependsFortran.cxx
+++ b/Source/cmDependsFortran.cxx
@@ -12,6 +12,7 @@
 
 #include "cmFortranParser.h" /* Interface to parser object.  */
 #include "cmGeneratedFileStream.h"
+#include "cmGlobalUnixMakefileGenerator3.h"
 #include "cmLocalUnixMakefileGenerator3.h"
 #include "cmMakefile.h"
 #include "cmOutputConverter.h"
@@ -320,14 +321,28 @@ bool cmDependsFortran::WriteDependenciesReal(std::string const& obj,
   std::string obj_i = this->MaybeConvertToRelativePath(binDir, obj);
   std::string obj_m = cmSystemTools::ConvertToOutputPath(obj_i);
   internalDepends << obj_i << "\n " << src << '\n';
-  for (std::string const& i : info.Includes) {
-    makeDepends << obj_m << ": "
-                << cmSystemTools::ConvertToOutputPath(
-                     this->MaybeConvertToRelativePath(binDir, i))
-                << '\n';
-    internalDepends << ' ' << i << '\n';
+  if (!info.Includes.empty()) {
+    const auto& lineContinue = static_cast<cmGlobalUnixMakefileGenerator3*>(
+                                 this->LocalGenerator->GetGlobalGenerator())
+                                 ->LineContinueDirective;
+    bool supportLongLineDepend = static_cast<cmGlobalUnixMakefileGenerator3*>(
+                                   this->LocalGenerator->GetGlobalGenerator())
+                                   ->SupportsLongLineDependencies();
+    if (supportLongLineDepend) {
+      makeDepends << obj_m << ':';
+    }
+    for (std::string const& i : info.Includes) {
+      std::string dependee = cmSystemTools::ConvertToOutputPath(
+        this->MaybeConvertToRelativePath(binDir, i));
+      if (supportLongLineDepend) {
+        makeDepends << ' ' << lineContinue << ' ' << dependee;
+      } else {
+        makeDepends << obj_m << ": " << dependee << '\n';
+      }
+      internalDepends << ' ' << i << '\n';
+    }
+    makeDepends << '\n';
   }
-  makeDepends << '\n';
 
   // Write module requirements to the output stream.
   for (std::string const& i : info.Requires) {