Do not duplicate build variables, reuse variables from cc toolchain

Before this cl each linking and compilation action would contain a full copy of
all build variables. However, some build variables can be reused, for the
memory consumption benefit. With this cl, we contruct a Variables instance in
the CcToolchain, and make it a parent of all per-linking and per-compilation
variables.

RELNOTES: None.
PiperOrigin-RevId: 169233756

1 files changed, 1 insertions, 2 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java
index 4d4a6c9286..c171c9fe01 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java
@@ -397,8 +397,7 @@ public final class LinkCommandLine extends CommandLine {
     argv.addAll(
         featureConfiguration.getCommandLine(
             actionName,
-            new Variables.Builder()
-                .addAll(variables)
+            new Variables.Builder(variables)
                 .addStringSequenceVariable(
                     CppLinkActionBuilder.LEGACY_LINK_FLAGS_VARIABLE, getToolchainFlags())
                 .build()));