Check all targets before generating shortnames

Bug: 421951995

Change-Id: I1ccd6cd9e8df1f1d80b88338ce3ce65cf8004f80
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/18820
Reviewed-by: Takuto Ikuta <tikuta@google.com>
Commit-Queue: Takuto Ikuta <tikuta@google.com>

src/gn/ninja_build_writer.cc

diff --git a/src/gn/ninja_build_writer.cc b/src/gn/ninja_build_writer.cc
index 5349948..ca8ff17 100644
--- a/src/gn/ninja_build_writer.cc
+++ b/src/gn/ninja_build_writer.cc
@@ -578,13 +578,15 @@
                dir_string.compare(2, label.name().size(), label.name()) == 0) {
       toplevel_dir_targets.push_back(target);
     }
+  }
 
-    // Add the output files from each target to the written rules so that
-    // we don't write phony rules that collide with anything generated by the
-    // build.
-    //
-    // If at this point there is a collision (no phony rules have been
-    // generated yet), two targets make the same output so throw an error.
+  // Add the output files from each target to the written rules so that
+  // we don't write phony rules that collide with anything generated by the
+  // build.
+  //
+  // If at this point there is a collision (no phony rules have been
+  // generated yet), two targets make the same output so throw an error.
+  for (const Target* target : all_targets_) {
     for (const auto& output : target->computed_outputs()) {
       // Need to normalize because many toolchain outputs will be preceded
       // with "./".