diff --git a/build.xml b/build.xml
index b640140f6c7..0ca66cdc154 100644
--- a/build.xml
+++ b/build.xml
@@ -10,6 +10,8 @@
     <!-- Set to false to disable compiler's javadoc generation. Speeds up the build -->
     <property name="generate.javadoc" value="true"/>
 
+    <property name="max.heap.size.for.forked.jvm" value="1024m"/>
+
     <property name="bootstrap.home" value="dependencies/bootstrap-compiler"/>
     <property name="bootstrap.compiler.home" value="${bootstrap.home}/Kotlin/kotlinc"/>
     <property name="bootstrap.runtime" value="${bootstrap.compiler.home}/lib/kotlin-runtime.jar"/>
@@ -258,7 +260,7 @@
 
             <pathconvert property="src.line" refid="src.path" pathsep=" "/>
 
-            <java classname="org.jetbrains.kotlin.cli.js.K2JSCompiler" failonerror="true" fork="true">
+            <java classname="org.jetbrains.kotlin.cli.js.K2JSCompiler" failonerror="true" fork="true" maxmemory="${max.heap.size.for.forked.jvm}">
                 <classpath>
                     <file file="${bootstrap.runtime}"/>
                     <pathelement location="${kotlin-home}/lib/kotlin-compiler.jar"/>
@@ -395,7 +397,8 @@
         <java classname="org.jetbrains.kotlin.preloading.Preloader"
               classpath="${bootstrap.compiler.home}/lib/kotlin-preloader.jar"
               failonerror="true"
-              fork="true">
+              fork="true"
+              maxmemory="${max.heap.size.for.forked.jvm}">
             <assertions>
                 <enable/>
             </assertions>
@@ -686,7 +689,7 @@
             <local name="src.line"/>
             <pathconvert property="src.line" refid="src.dirset" pathsep=" "/>
 
-            <java classname="org.jetbrains.kotlin.cli.jvm.K2JVMCompiler" failonerror="true" fork="true">
+            <java classname="org.jetbrains.kotlin.cli.jvm.K2JVMCompiler" failonerror="true" fork="true" maxmemory="${max.heap.size.for.forked.jvm}">
                 <classpath>
                     <file file="${bootstrap.runtime}"/>
                     <pathelement location="${kotlin-home}/lib/kotlin-compiler.jar"/>