Auto merge of rust-lang#89183 - cjgillot:noenc, r=oli-obk

bors · bors · commit 1c0ed0d4c4bd · 2021-10-01T00:35:35.000Z
Move encode_metadata out of CrateStore.

`rustc_metadata` is already accessible by all client crates. It does not need to be called trough a trait object.
diff --git a/Cargo.lock b/Cargo.lock
@@ -3706,6 +3706,7 @@ dependencies = [
  "rustc_incremental",
  "rustc_index",
  "rustc_macros",
+ "rustc_metadata",
  "rustc_middle",
  "rustc_serialize",
  "rustc_session",
diff --git a/compiler/rustc_codegen_cranelift/scripts/filter_profile.rs b/compiler/rustc_codegen_cranelift/scripts/filter_profile.rs
@@ -96,7 +96,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
             stack = &stack[..index + REPORT_SYMBOL_NAMES.len()];
         }
 
-        const ENCODE_METADATA: &str = "rustc_middle::ty::context::TyCtxt::encode_metadata";
+        const ENCODE_METADATA: &str = "rustc_metadata::rmeta::encoder::encode_metadata";
         if let Some(index) = stack.find(ENCODE_METADATA) {
             stack = &stack[..index + ENCODE_METADATA.len()];
         }
diff --git a/compiler/rustc_codegen_cranelift/src/driver/aot.rs b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
@@ -6,8 +6,8 @@ use std::path::PathBuf;
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
 use rustc_codegen_ssa::{CodegenResults, CompiledModule, CrateInfo, ModuleKind};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
-use rustc_middle::middle::cstore::EncodedMetadata;
 use rustc_middle::mir::mono::{CodegenUnit, MonoItem};
 use rustc_session::cgu_reuse_tracker::CguReuse;
 use rustc_session::config::{DebugInfo, OutputType};
diff --git a/compiler/rustc_codegen_cranelift/src/lib.rs b/compiler/rustc_codegen_cranelift/src/lib.rs
@@ -30,8 +30,8 @@ use std::any::Any;
 use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_codegen_ssa::CodegenResults;
 use rustc_errors::ErrorReported;
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
-use rustc_middle::middle::cstore::EncodedMetadata;
 use rustc_session::config::OutputFilenames;
 use rustc_session::Session;
 
diff --git a/compiler/rustc_codegen_cranelift/src/metadata.rs b/compiler/rustc_codegen_cranelift/src/metadata.rs
@@ -3,16 +3,20 @@
 use object::write::{Object, StandardSegment, Symbol, SymbolSection};
 use object::{SectionKind, SymbolFlags, SymbolKind, SymbolScope};
 
-use rustc_middle::middle::cstore::EncodedMetadata;
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::ty::TyCtxt;
 
 // Adapted from https://github.com/rust-lang/rust/blob/da573206f87b5510de4b0ee1a9c044127e409bd3/src/librustc_codegen_llvm/base.rs#L47-L112
-pub(crate) fn new_metadata_object(tcx: TyCtxt<'_>, cgu_name: &str, metadata: &EncodedMetadata) -> Vec<u8> {
+pub(crate) fn new_metadata_object(
+    tcx: TyCtxt<'_>,
+    cgu_name: &str,
+    metadata: &EncodedMetadata,
+) -> Vec<u8> {
     use snap::write::FrameEncoder;
     use std::io::Write;
 
     let mut compressed = rustc_metadata::METADATA_HEADER.to_vec();
-    FrameEncoder::new(&mut compressed).write_all(&metadata.raw_data).unwrap();
+    FrameEncoder::new(&mut compressed).write_all(metadata.raw_data()).unwrap();
 
     let triple = crate::target_triple(tcx.sess);
 
diff --git a/compiler/rustc_codegen_gcc/src/base.rs b/compiler/rustc_codegen_gcc/src/base.rs
@@ -7,14 +7,14 @@ use gccjit::{
     GlobalKind,
 };
 use rustc_middle::dep_graph;
-use rustc_middle::middle::cstore::EncodedMetadata;
 use rustc_middle::middle::exported_symbols;
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::mir::mono::Linkage;
 use rustc_codegen_ssa::{ModuleCodegen, ModuleKind};
 use rustc_codegen_ssa::base::maybe_create_entry_wrapper;
 use rustc_codegen_ssa::mono_item::MonoItemExt;
 use rustc_codegen_ssa::traits::DebugInfoMethods;
+use rustc_metadata::EncodedMetadata;
 use rustc_session::config::DebugInfo;
 use rustc_span::Symbol;
 
@@ -149,7 +149,7 @@ pub fn write_compressed_metadata<'tcx>(tcx: TyCtxt<'tcx>, metadata: &EncodedMeta
 
     let context = &gcc_module.context;
     let mut compressed = rustc_metadata::METADATA_HEADER.to_vec();
-    FrameEncoder::new(&mut compressed).write_all(&metadata.raw_data).unwrap();
+    FrameEncoder::new(&mut compressed).write_all(&metadata.raw_data()).unwrap();
 
     let name = exported_symbols::metadata_symbol_name(tcx);
     let typ = context.new_array_type(None, context.new_type::<u8>(), compressed.len() as i32);
diff --git a/compiler/rustc_codegen_gcc/src/lib.rs b/compiler/rustc_codegen_gcc/src/lib.rs
@@ -60,8 +60,8 @@ use rustc_codegen_ssa::target_features::supported_target_features;
 use rustc_codegen_ssa::traits::{CodegenBackend, ExtraBackendMethods, ModuleBufferMethods, ThinBufferMethods, WriteBackendMethods};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{ErrorReported, Handler};
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
-use rustc_middle::middle::cstore::EncodedMetadata;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{Lto, OptLevel, OutputFilenames};
 use rustc_session::Session;
diff --git a/compiler/rustc_codegen_llvm/src/base.rs b/compiler/rustc_codegen_llvm/src/base.rs
@@ -25,9 +25,9 @@ use rustc_codegen_ssa::mono_item::MonoItemExt;
 use rustc_codegen_ssa::traits::*;
 use rustc_codegen_ssa::{ModuleCodegen, ModuleKind};
 use rustc_data_structures::small_c_str::SmallCStr;
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
-use rustc_middle::middle::cstore::EncodedMetadata;
 use rustc_middle::middle::exported_symbols;
 use rustc_middle::mir::mono::{Linkage, Visibility};
 use rustc_middle::ty::TyCtxt;
@@ -64,7 +64,7 @@ pub fn write_compressed_metadata<'tcx>(
 
     let (metadata_llcx, metadata_llmod) = (&*llvm_module.llcx, llvm_module.llmod());
     let mut compressed = rustc_metadata::METADATA_HEADER.to_vec();
-    FrameEncoder::new(&mut compressed).write_all(&metadata.raw_data).unwrap();
+    FrameEncoder::new(&mut compressed).write_all(metadata.raw_data()).unwrap();
 
     let llmeta = common::bytes_in_context(metadata_llcx, &compressed);
     let llconst = common::struct_in_context(metadata_llcx, &[llmeta], false);
diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs
@@ -27,8 +27,8 @@ use rustc_codegen_ssa::ModuleCodegen;
 use rustc_codegen_ssa::{CodegenResults, CompiledModule};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{ErrorReported, FatalError, Handler};
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
-use rustc_middle::middle::cstore::EncodedMetadata;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{OptLevel, OutputFilenames, PrintRequest};
 use rustc_session::Session;
diff --git a/compiler/rustc_codegen_ssa/Cargo.toml b/compiler/rustc_codegen_ssa/Cargo.toml
@@ -32,6 +32,7 @@ rustc_hir = { path = "../rustc_hir" }
 rustc_incremental = { path = "../rustc_incremental" }
 rustc_index = { path = "../rustc_index" }
 rustc_macros = { path = "../rustc_macros" }
+rustc_metadata = { path = "../rustc_metadata" }
 rustc_target = { path = "../rustc_target" }
 rustc_session = { path = "../rustc_session" }
 
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -327,7 +327,7 @@ fn link_rlib<'a, B: ArchiveBuilder<'a>>(
             // metadata in rlib files is wrapped in a "dummy" object file for
             // the target platform so the rlib can be processed entirely by
             // normal linkers for the platform.
-            let metadata = create_metadata_file(sess, &codegen_results.metadata.raw_data);
+            let metadata = create_metadata_file(sess, codegen_results.metadata.raw_data());
             ab.add_file(&emit_metadata(sess, &metadata, tmpdir));
 
             // After adding all files to the archive, we need to update the
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -21,8 +21,8 @@ use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_incremental::{
     copy_cgu_workproduct_to_incr_comp_cache_dir, in_incr_comp_dir, in_incr_comp_dir_sess,
 };
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
-use rustc_middle::middle::cstore::EncodedMetadata;
 use rustc_middle::middle::exported_symbols::SymbolExportLevel;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::cgu_reuse_tracker::CguReuseTracker;
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
@@ -18,8 +18,8 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::lang_items::LangItem;
 use rustc_index::vec::Idx;
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
-use rustc_middle::middle::cstore::EncodedMetadata;
 use rustc_middle::middle::lang_items;
 use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, MonoItem};
 use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, TyAndLayout};
diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -158,7 +158,7 @@ pub struct CodegenResults {
     pub modules: Vec<CompiledModule>,
     pub allocator_module: Option<CompiledModule>,
     pub metadata_module: Option<CompiledModule>,
-    pub metadata: rustc_middle::middle::cstore::EncodedMetadata,
+    pub metadata: rustc_metadata::EncodedMetadata,
     pub crate_info: CrateInfo,
 }
 
diff --git a/compiler/rustc_codegen_ssa/src/traits/backend.rs b/compiler/rustc_codegen_ssa/src/traits/backend.rs
@@ -6,8 +6,9 @@ use crate::{CodegenResults, ModuleCodegen};
 use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::ErrorReported;
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
-use rustc_middle::middle::cstore::{EncodedMetadata, MetadataLoaderDyn};
+use rustc_middle::middle::cstore::MetadataLoaderDyn;
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt, LayoutOf, TyAndLayout};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{Ty, TyCtxt};
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
@@ -16,9 +16,9 @@ use rustc_hir::def_id::{StableCrateId, LOCAL_CRATE};
 use rustc_hir::Crate;
 use rustc_lint::LintStore;
 use rustc_metadata::creader::CStore;
+use rustc_metadata::{encode_metadata, EncodedMetadata};
 use rustc_middle::arena::Arena;
 use rustc_middle::dep_graph::DepGraph;
-use rustc_middle::middle;
 use rustc_middle::middle::cstore::{MetadataLoader, MetadataLoaderDyn};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, GlobalCtxt, ResolverOutputs, TyCtxt};
@@ -977,7 +977,7 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
 fn encode_and_write_metadata(
     tcx: TyCtxt<'_>,
     outputs: &OutputFilenames,
-) -> (middle::cstore::EncodedMetadata, bool) {
+) -> (EncodedMetadata, bool) {
     #[derive(PartialEq, Eq, PartialOrd, Ord)]
     enum MetadataKind {
         None,
@@ -1000,8 +1000,8 @@ fn encode_and_write_metadata(
         .unwrap_or(MetadataKind::None);
 
     let metadata = match metadata_kind {
-        MetadataKind::None => middle::cstore::EncodedMetadata::new(),
-        MetadataKind::Uncompressed | MetadataKind::Compressed => tcx.encode_metadata(),
+        MetadataKind::None => EncodedMetadata::new(),
+        MetadataKind::Uncompressed | MetadataKind::Compressed => encode_metadata(tcx),
     };
 
     let _prof_timer = tcx.sess.prof.generic_activity("write_crate_metadata");
@@ -1020,7 +1020,7 @@ fn encode_and_write_metadata(
             .tempdir_in(out_filename.parent().unwrap())
             .unwrap_or_else(|err| tcx.sess.fatal(&format!("couldn't create a temp dir: {}", err)));
         let metadata_tmpdir = MaybeTempDir::new(metadata_tmpdir, tcx.sess.opts.cg.save_temps);
-        let metadata_filename = emit_metadata(tcx.sess, &metadata.raw_data, &metadata_tmpdir);
+        let metadata_filename = emit_metadata(tcx.sess, metadata.raw_data(), &metadata_tmpdir);
         if let Err(e) = util::non_durable_rename(&metadata_filename, &out_filename) {
             tcx.sess.fatal(&format!("failed to write {}: {}", out_filename.display(), e));
         }
diff --git a/compiler/rustc_metadata/src/lib.rs b/compiler/rustc_metadata/src/lib.rs
@@ -30,4 +30,4 @@ pub mod creader;
 pub mod dynamic_lib;
 pub mod locator;
 
-pub use rmeta::METADATA_HEADER;
+pub use rmeta::{encode_metadata, EncodedMetadata, METADATA_HEADER};
diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -1,7 +1,6 @@
 use crate::creader::{CStore, LoadedMacro};
 use crate::foreign_modules;
 use crate::native_libs;
-use crate::rmeta::encoder;
 
 use rustc_ast as ast;
 use rustc_data_structures::stable_map::FxHashMap;
@@ -10,7 +9,7 @@ use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, CRATE_DEF_INDEX, LOCAL_CRATE}
 use rustc_hir::definitions::{DefKey, DefPath, DefPathHash};
 use rustc_middle::hir::exports::Export;
 use rustc_middle::middle::cstore::ForeignModule;
-use rustc_middle::middle::cstore::{CrateSource, CrateStore, EncodedMetadata};
+use rustc_middle::middle::cstore::{CrateSource, CrateStore};
 use rustc_middle::middle::exported_symbols::ExportedSymbol;
 use rustc_middle::middle::stability::DeprecationEntry;
 use rustc_middle::ty::query::Providers;
@@ -511,8 +510,4 @@ impl CrateStore for CStore {
     fn expn_hash_to_expn_id(&self, cnum: CrateNum, index_guess: u32, hash: ExpnHash) -> ExpnId {
         self.get_crate_data(cnum).expn_hash_to_expn_id(index_guess, hash)
     }
-
-    fn encode_metadata(&self, tcx: TyCtxt<'_>) -> EncodedMetadata {
-        encoder::encode_metadata(tcx)
-    }
 }
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -18,7 +18,7 @@ use rustc_hir::{AnonConst, GenericParamKind};
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_index::vec::Idx;
 use rustc_middle::hir::map::Map;
-use rustc_middle::middle::cstore::{EncodedMetadata, ForeignModule, LinkagePreference, NativeLib};
+use rustc_middle::middle::cstore::{ForeignModule, LinkagePreference, NativeLib};
 use rustc_middle::middle::dependency_format::Linkage;
 use rustc_middle::middle::exported_symbols::{
     metadata_symbol_name, ExportedSymbol, SymbolExportLevel,
@@ -2101,7 +2101,26 @@ fn prefetch_mir(tcx: TyCtxt<'_>) {
 // will allow us to slice the metadata to the precise length that we just
 // generated regardless of trailing bytes that end up in it.
 
-pub(super) fn encode_metadata(tcx: TyCtxt<'_>) -> EncodedMetadata {
+#[derive(Encodable, Decodable)]
+pub struct EncodedMetadata {
+    raw_data: Vec<u8>,
+}
+
+impl EncodedMetadata {
+    #[inline]
+    pub fn new() -> EncodedMetadata {
+        EncodedMetadata { raw_data: Vec::new() }
+    }
+
+    #[inline]
+    pub fn raw_data(&self) -> &[u8] {
+        &self.raw_data[..]
+    }
+}
+
+pub fn encode_metadata(tcx: TyCtxt<'_>) -> EncodedMetadata {
+    let _prof_timer = tcx.prof.verbose_generic_activity("generate_crate_metadata");
+
     // Since encoding metadata is not in a query, and nothing is cached,
     // there's no need to do dep-graph tracking for any of it.
     tcx.dep_graph.assert_ignored();
diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -33,6 +33,7 @@ use decoder::DecodeContext;
 pub use decoder::{provide, provide_extern};
 crate use decoder::{CrateMetadata, CrateNumMap, MetadataBlob};
 use encoder::EncodeContext;
+pub use encoder::{encode_metadata, EncodedMetadata};
 use rustc_span::hygiene::SyntaxContextData;
 
 mod decoder;
diff --git a/compiler/rustc_middle/src/middle/cstore.rs b/compiler/rustc_middle/src/middle/cstore.rs
@@ -2,8 +2,6 @@
 //! are *mostly* used as a part of that interface, but these should
 //! probably get a better home if someone can find one.
 
-use crate::ty::TyCtxt;
-
 use rustc_ast as ast;
 use rustc_data_structures::sync::{self, MetadataRef};
 use rustc_hir::def_id::{CrateNum, DefId, StableCrateId, LOCAL_CRATE};
@@ -150,17 +148,6 @@ pub enum ExternCrateSource {
     Path,
 }
 
-#[derive(Encodable, Decodable)]
-pub struct EncodedMetadata {
-    pub raw_data: Vec<u8>,
-}
-
-impl EncodedMetadata {
-    pub fn new() -> EncodedMetadata {
-        EncodedMetadata { raw_data: Vec::new() }
-    }
-}
-
 /// The backend's way to give the crate store access to the metadata in a library.
 /// Note that it returns the raw metadata bytes stored in the library file, whether
 /// it is compressed, uncompressed, some weird mix, etc.
@@ -204,9 +191,6 @@ pub trait CrateStore: std::fmt::Debug {
     /// Fetch a DefId from a DefPathHash for a foreign crate.
     fn def_path_hash_to_def_id(&self, cnum: CrateNum, hash: DefPathHash) -> DefId;
     fn expn_hash_to_expn_id(&self, cnum: CrateNum, index_guess: u32, hash: ExpnHash) -> ExpnId;
-
-    // utility functions
-    fn encode_metadata(&self, tcx: TyCtxt<'_>) -> EncodedMetadata;
 }
 
 pub type CrateStoreDyn = dyn CrateStore + sync::Sync;
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
@@ -7,7 +7,6 @@ use crate::ich::{NodeIdHashingMode, StableHashingContext};
 use crate::infer::canonical::{Canonical, CanonicalVarInfo, CanonicalVarInfos};
 use crate::lint::{struct_lint_level, LintDiagnosticBuilder, LintLevelSource};
 use crate::middle;
-use crate::middle::cstore::EncodedMetadata;
 use crate::middle::resolve_lifetime::{self, LifetimeScopeForPath, ObjectLifetimeDefault};
 use crate::middle::stability;
 use crate::mir::interpret::{self, AllocId, Allocation, ConstValue, Scalar};
@@ -1324,11 +1323,6 @@ impl<'tcx> TyCtxt<'tcx> {
         )
     }
 
-    pub fn encode_metadata(self) -> EncodedMetadata {
-        let _prof_timer = self.prof.verbose_generic_activity("generate_crate_metadata");
-        self.untracked_resolutions.cstore.encode_metadata(self)
-    }
-
     /// Note that this is *untracked* and should only be used within the query
     /// system if the result is otherwise tracked through queries
     pub fn cstore_untracked(self) -> &'tcx ty::CrateStoreDyn {
diff --git a/src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs b/src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs
@@ -2,11 +2,12 @@
 #![deny(warnings)]
 
 extern crate rustc_codegen_ssa;
-extern crate rustc_errors;
-extern crate rustc_middle;
 extern crate rustc_data_structures;
 extern crate rustc_driver;
+extern crate rustc_errors;
 extern crate rustc_hir;
+extern crate rustc_metadata;
+extern crate rustc_middle;
 extern crate rustc_session;
 extern crate rustc_span;
 extern crate rustc_symbol_mangling;
@@ -16,8 +17,8 @@ use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_codegen_ssa::{CodegenResults, CrateInfo};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::ErrorReported;
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
-use rustc_middle::middle::cstore::EncodedMetadata;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::OutputFilenames;
 use rustc_session::Session;

Original file line number	Diff line number	Diff line change
`@@ -96,7 +96,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {`
`96`	`96`	`stack = &stack[..index + REPORT_SYMBOL_NAMES.len()];`
`97`	`97`	`}`
`98`	`98`
`99`		`- const ENCODE_METADATA: &str = "rustc_middle::ty::context::TyCtxt::encode_metadata";`
	`99`	`+ const ENCODE_METADATA: &str = "rustc_metadata::rmeta::encoder::encode_metadata";`
`100`	`100`	`if let Some(index) = stack.find(ENCODE_METADATA) {`
`101`	`101`	`stack = &stack[..index + ENCODE_METADATA.len()];`
`102`	`102`	`}`