Add sort_bss_symbols_by_size property for shared libs
If sort_bss_symbols_by_size is true, a shared library is built twice.
The first build generates an unsorted output file, which is used to
generate the symbol ordering file. The output of the second build is
a shared library with its bss symbols sorted by their size.
With this, the only user of symbol_ordering_file, libc, is migrated to
use the new property, so we remove symbol_ordering_file support as well.
Bug: 135754984
Test: Build and check the resulting libc.so has its bss symbols sorted.
Change-Id: I5c892b44d82eb99cbc070cfa2c680be3087f3364
diff --git a/cc/library.go b/cc/library.go
index 7cbfdb5..2b7c9a1 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -110,6 +110,9 @@
// Symbol tags that should be ignored from the symbol file
Exclude_symbol_tags []string
}
+
+ // Order symbols in .bss section by their sizes. Only useful for shared libraries.
+ Sort_bss_symbols_by_size *bool
}
type LibraryMutatedProperties struct {
@@ -758,6 +761,18 @@
linkerDeps = append(linkerDeps, deps.LateSharedLibsDeps...)
linkerDeps = append(linkerDeps, objs.tidyFiles...)
+ if Bool(library.Properties.Sort_bss_symbols_by_size) {
+ unsortedOutputFile := android.PathForModuleOut(ctx, "unsorted", fileName)
+ TransformObjToDynamicBinary(ctx, objs.objFiles, sharedLibs,
+ deps.StaticLibs, deps.LateStaticLibs, deps.WholeStaticLibs,
+ linkerDeps, deps.CrtBegin, deps.CrtEnd, false, builderFlags, unsortedOutputFile, implicitOutputs)
+
+ symbolOrderingFile := android.PathForModuleOut(ctx, "unsorted", fileName+".symbol_order")
+ symbolOrderingFlag := library.baseLinker.sortBssSymbolsBySize(ctx, unsortedOutputFile, symbolOrderingFile, builderFlags)
+ builderFlags.ldFlags += " " + symbolOrderingFlag
+ linkerDeps = append(linkerDeps, symbolOrderingFile)
+ }
+
TransformObjToDynamicBinary(ctx, objs.objFiles, sharedLibs,
deps.StaticLibs, deps.LateStaticLibs, deps.WholeStaticLibs,
linkerDeps, deps.CrtBegin, deps.CrtEnd, false, builderFlags, outputFile, implicitOutputs)
diff --git a/cc/linker.go b/cc/linker.go
index fa3b0a6..daacec1 100644
--- a/cc/linker.go
+++ b/cc/linker.go
@@ -147,9 +147,6 @@
// local file name to pass to the linker as --version_script
Version_script *string `android:"path,arch_variant"`
-
- // Local file name to pass to the linker as --symbol-ordering-file
- Symbol_ordering_file *string `android:"arch_variant"`
}
func NewBaseLinker(sanitize *sanitize) *baseLinker {
@@ -442,16 +439,6 @@
}
}
- if !linker.dynamicProperties.BuildStubs {
- symbolOrderingFile := ctx.ExpandOptionalSource(
- linker.Properties.Symbol_ordering_file, "Symbol_ordering_file")
- if symbolOrderingFile.Valid() {
- flags.LdFlags = append(flags.LdFlags,
- "-Wl,--symbol-ordering-file,"+symbolOrderingFile.String())
- flags.LdFlagsDeps = append(flags.LdFlagsDeps, symbolOrderingFile.Path())
- }
- }
-
return flags
}
@@ -487,3 +474,29 @@
},
})
}
+
+// Rule to generate .bss symbol ordering file.
+
+var (
+ _ = pctx.SourcePathVariable("genSortedBssSymbolsPath", "build/soong/scripts/gen_sorted_bss_symbols.sh")
+ gen_sorted_bss_symbols = pctx.AndroidStaticRule("gen_sorted_bss_symbols",
+ blueprint.RuleParams{
+ Command: "CROSS_COMPILE=$crossCompile $genSortedBssSymbolsPath ${in} ${out}",
+ CommandDeps: []string{"$genSortedBssSymbolsPath"},
+ },
+ "crossCompile")
+)
+
+func (linker *baseLinker) sortBssSymbolsBySize(ctx ModuleContext, in android.Path, symbolOrderingFile android.ModuleOutPath, flags builderFlags) string {
+ crossCompile := gccCmd(flags.toolchain, "")
+ ctx.Build(pctx, android.BuildParams{
+ Rule: gen_sorted_bss_symbols,
+ Description: "generate bss symbol order " + symbolOrderingFile.Base(),
+ Output: symbolOrderingFile,
+ Input: in,
+ Args: map[string]string{
+ "crossCompile": crossCompile,
+ },
+ })
+ return "-Wl,--symbol-ordering-file," + symbolOrderingFile.String()
+}