In general, a gensrc directory is a package root, meaning that the subdirectories of gensrc/ are typically directories like com/, sun/, java/, javax/, etc

But CompilerProperties.java breaks the guideline and has an extra "share/classes", as shown here:

$ find build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javah
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javah/resources
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javah/resources/l10n_zh_CN.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javah/resources/l10n_ja.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javah/resources/version.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javah/resources/l10n.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javah/resources/version.properties
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources/javac.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources/ct.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources/version.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources/legacy.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources/javac_ja.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources/compiler_zh_CN.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources/javac_zh_CN.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources/compiler_ja.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources/compiler.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javac/resources/version.properties
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/doclint
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/doclint/resources
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/doclint/resources/doclint_ja.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/doclint/resources/doclint_zh_CN.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/doclint/resources/doclint.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javap
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javap/resources
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javap/resources/javap_ja.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javap/resources/javap.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javap/resources/version.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javap/resources/version.properties
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/com/sun/tools/javap/resources/javap_zh_CN.java
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/_the_parsed_props
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/_the_props
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com/sun
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com/sun/tools
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com/sun/tools/javac
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com/sun/tools/javac/resources
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com/sun/tools/javac/resources/CompilerProperties.java

FWIW, jdk.compiler is the only subdirectory of gensrc to have a share/ component

$ find build/linux-x86_64-normal-server-release/support/gensrc/*/share
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com/sun
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com/sun/tools
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com/sun/tools/javac
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com/sun/tools/javac/resources
build/linux-x86_64-normal-server-release/support/gensrc/jdk.compiler/share/classes/com/sun/tools/javac/resources/CompilerProperties.java