Split Rust crate builds into compile and link phases.

Teach rustc to generate object files instead of a linked executable
for binary and shared library crates. This lets us skip the lengthy
Rust compilation phase when only the C++ dependencies of these crates
have changed.

This works using a Python script that replaces the linker invoked by
rustc and converts the linker command line into a rspfile that can be
used during the link phase. The script makes certain assumptions about
how rustc invokes the linker, but since we control the version of Rust
we use, we can update the script if those assumptions ever break. I've
asked the Rust developers about adding an official way to do this so
hopefully we won't need to rely on this hack in the future.

The rustc rule for Kythe has been altered to pass linker=true, somewhat
consistent with the main rustc rule, which now doesn't invoke the actual
linker either. `m xref_rust` still succeeds, but hopefully we can find
someone who knows more about the rest of the Kythe pipeline who can let
us know whether it should still work. Otherwise, let's use this CL as
an opportunity to find out whether the rest of the pipeline is happy
with linker=true, since otherwise we will find it hard to maintain the
Kythe rule in the future.

Change-Id: Ifb9c8689c1bd78c0afcf6fdfd111140d20377536
This commit is contained in:
Peter Collingbourne
2023-03-31 20:21:19 -07:00
parent 38c39aff61
commit e7c71c344d
13 changed files with 201 additions and 92 deletions

View File

@@ -26,14 +26,14 @@ import (
var (
_ = pctx.SourcePathVariable("rustcCmd", "${config.RustBin}/rustc")
_ = pctx.SourcePathVariable("mkcraterspCmd", "build/soong/scripts/mkcratersp.py")
rustc = pctx.AndroidStaticRule("rustc",
blueprint.RuleParams{
Command: "$envVars $rustcCmd " +
"-C linker=${config.RustLinker} " +
"-C link-args=\"${crtBegin} ${config.RustLinkerArgs} ${linkFlags} ${crtEnd}\" " +
"-C linker=$mkcraterspCmd " +
"--emit link -o $out --emit dep-info=$out.d.raw $in ${libFlags} $rustcFlags" +
" && grep \"^$out:\" $out.d.raw > $out.d",
CommandDeps: []string{"$rustcCmd"},
CommandDeps: []string{"$rustcCmd", "$mkcraterspCmd"},
// Rustc deps-info writes out make compatible dep files: https://github.com/rust-lang/rust/issues/7633
// Rustc emits unneeded dependency lines for the .d and input .rs files.
// Those extra lines cause ninja warning:
@@ -42,7 +42,12 @@ var (
Deps: blueprint.DepsGCC,
Depfile: "$out.d",
},
"rustcFlags", "linkFlags", "libFlags", "crtBegin", "crtEnd", "envVars")
"rustcFlags", "libFlags", "envVars")
rustLink = pctx.AndroidStaticRule("rustLink",
blueprint.RuleParams{
Command: "${config.RustLinker} -o $out ${crtBegin} ${config.RustLinkerArgs} @$in ${linkFlags} ${crtEnd}",
},
"linkFlags", "crtBegin", "crtEnd")
_ = pctx.SourcePathVariable("rustdocCmd", "${config.RustBin}/rustdoc")
rustdoc = pctx.AndroidStaticRule("rustdoc",
@@ -101,14 +106,13 @@ var (
`KYTHE_CANONICALIZE_VNAME_PATHS=prefer-relative ` +
`$rustExtractor $envVars ` +
`$rustcCmd ` +
`-C linker=${config.RustLinker} ` +
`-C link-args="${crtBegin} ${config.RustLinkerArgs} ${linkFlags} ${crtEnd}" ` +
`-C linker=true ` +
`$in ${libFlags} $rustcFlags`,
CommandDeps: []string{"$rustExtractor", "$kytheVnames"},
Rspfile: "${out}.rsp",
RspfileContent: "$in",
},
"rustcFlags", "linkFlags", "libFlags", "crtBegin", "crtEnd", "envVars")
"rustcFlags", "libFlags", "envVars")
)
type buildOutput struct {
@@ -220,11 +224,9 @@ func transformSrctoCrate(ctx ModuleContext, main android.Path, deps PathDeps, fl
outputFile android.WritablePath, crateType string) buildOutput {
var inputs android.Paths
var implicits android.Paths
var orderOnly android.Paths
var implicits, linkImplicits, linkOrderOnly android.Paths
var output buildOutput
var rustcFlags, linkFlags []string
var implicitOutputs android.WritablePaths
output.outputFile = outputFile
crateName := ctx.RustModule().CrateName()
@@ -281,15 +283,15 @@ func transformSrctoCrate(ctx ModuleContext, main android.Path, deps PathDeps, fl
implicits = append(implicits, rustLibsToPaths(deps.RLibs)...)
implicits = append(implicits, rustLibsToPaths(deps.DyLibs)...)
implicits = append(implicits, rustLibsToPaths(deps.ProcMacros)...)
implicits = append(implicits, deps.StaticLibs...)
implicits = append(implicits, deps.SharedLibDeps...)
implicits = append(implicits, deps.srcProviderFiles...)
implicits = append(implicits, deps.AfdoProfiles...)
implicits = append(implicits, deps.srcProviderFiles...)
implicits = append(implicits, deps.WholeStaticLibs...)
implicits = append(implicits, deps.CrtBegin...)
implicits = append(implicits, deps.CrtEnd...)
linkImplicits = append(linkImplicits, deps.LibDeps...)
linkImplicits = append(linkImplicits, deps.CrtBegin...)
linkImplicits = append(linkImplicits, deps.CrtEnd...)
orderOnly = append(orderOnly, deps.SharedLibs...)
linkOrderOnly = append(linkOrderOnly, deps.linkObjects...)
if len(deps.SrcDeps) > 0 {
moduleGenDir := ctx.RustModule().compiler.CargoOutDir()
@@ -328,16 +330,16 @@ func transformSrctoCrate(ctx ModuleContext, main android.Path, deps PathDeps, fl
}
}
envVars = append(envVars, "AR=${cc_config.ClangBin}/llvm-ar")
if flags.Clippy {
clippyFile := android.PathForModuleOut(ctx, outputFile.Base()+".clippy")
ctx.Build(pctx, android.BuildParams{
Rule: clippyDriver,
Description: "clippy " + main.Rel(),
Output: clippyFile,
ImplicitOutputs: nil,
Inputs: inputs,
Implicits: implicits,
OrderOnly: orderOnly,
Rule: clippyDriver,
Description: "clippy " + main.Rel(),
Output: clippyFile,
Inputs: inputs,
Implicits: implicits,
Args: map[string]string{
"rustcFlags": strings.Join(rustcFlags, " "),
"libFlags": strings.Join(libFlags, " "),
@@ -349,24 +351,41 @@ func transformSrctoCrate(ctx ModuleContext, main android.Path, deps PathDeps, fl
implicits = append(implicits, clippyFile)
}
rustcOutputFile := outputFile
usesLinker := crateType == "bin" || crateType == "dylib" || crateType == "cdylib" || crateType == "proc-macro"
if usesLinker {
rustcOutputFile = android.PathForModuleOut(ctx, outputFile.Base()+".rsp")
}
ctx.Build(pctx, android.BuildParams{
Rule: rustc,
Description: "rustc " + main.Rel(),
Output: outputFile,
ImplicitOutputs: implicitOutputs,
Inputs: inputs,
Implicits: implicits,
OrderOnly: orderOnly,
Rule: rustc,
Description: "rustc " + main.Rel(),
Output: rustcOutputFile,
Inputs: inputs,
Implicits: implicits,
Args: map[string]string{
"rustcFlags": strings.Join(rustcFlags, " "),
"linkFlags": strings.Join(linkFlags, " "),
"libFlags": strings.Join(libFlags, " "),
"crtBegin": strings.Join(deps.CrtBegin.Strings(), " "),
"crtEnd": strings.Join(deps.CrtEnd.Strings(), " "),
"envVars": strings.Join(envVars, " "),
},
})
if usesLinker {
ctx.Build(pctx, android.BuildParams{
Rule: rustLink,
Description: "rustLink " + main.Rel(),
Output: outputFile,
Inputs: android.Paths{rustcOutputFile},
Implicits: linkImplicits,
OrderOnly: linkOrderOnly,
Args: map[string]string{
"linkFlags": strings.Join(linkFlags, " "),
"crtBegin": strings.Join(deps.CrtBegin.Strings(), " "),
"crtEnd": strings.Join(deps.CrtEnd.Strings(), " "),
},
})
}
if flags.EmitXrefs {
kytheFile := android.PathForModuleOut(ctx, outputFile.Base()+".kzip")
ctx.Build(pctx, android.BuildParams{
@@ -375,13 +394,9 @@ func transformSrctoCrate(ctx ModuleContext, main android.Path, deps PathDeps, fl
Output: kytheFile,
Inputs: inputs,
Implicits: implicits,
OrderOnly: orderOnly,
Args: map[string]string{
"rustcFlags": strings.Join(rustcFlags, " "),
"linkFlags": strings.Join(linkFlags, " "),
"libFlags": strings.Join(libFlags, " "),
"crtBegin": strings.Join(deps.CrtBegin.Strings(), " "),
"crtEnd": strings.Join(deps.CrtEnd.Strings(), " "),
"envVars": strings.Join(envVars, " "),
},
})