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-rw-r--r--wasm/MarkLive.cpp120
1 files changed, 0 insertions, 120 deletions
diff --git a/wasm/MarkLive.cpp b/wasm/MarkLive.cpp
deleted file mode 100644
index 3bbd1148f6ad..000000000000
--- a/wasm/MarkLive.cpp
+++ /dev/null
@@ -1,120 +0,0 @@
-//===- MarkLive.cpp -------------------------------------------------------===//
-//
-// The LLVM Linker
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements --gc-sections, which is a feature to remove unused
-// chunks from the output. Unused chunks are those that are not reachable from
-// known root symbols or chunks. This feature is implemented as a mark-sweep
-// garbage collector.
-//
-// Here's how it works. Each InputChunk has a "Live" bit. The bit is off by
-// default. Starting with the GC-roots, visit all reachable chunks and set their
-// Live bits. The Writer will then ignore chunks whose Live bits are off, so
-// that such chunk are not appear in the output.
-//
-//===----------------------------------------------------------------------===//
-
-#include "MarkLive.h"
-#include "Config.h"
-#include "InputChunks.h"
-#include "InputEvent.h"
-#include "InputGlobal.h"
-#include "SymbolTable.h"
-#include "Symbols.h"
-
-#define DEBUG_TYPE "lld"
-
-using namespace llvm;
-using namespace llvm::wasm;
-
-void lld::wasm::markLive() {
- if (!Config->GcSections)
- return;
-
- LLVM_DEBUG(dbgs() << "markLive\n");
- SmallVector<InputChunk *, 256> Q;
-
- auto Enqueue = [&](Symbol *Sym) {
- if (!Sym || Sym->isLive())
- return;
- LLVM_DEBUG(dbgs() << "markLive: " << Sym->getName() << "\n");
- Sym->markLive();
- if (InputChunk *Chunk = Sym->getChunk())
- Q.push_back(Chunk);
- };
-
- // Add GC root symbols.
- if (!Config->Entry.empty())
- Enqueue(Symtab->find(Config->Entry));
- Enqueue(WasmSym::CallCtors);
-
- // We need to preserve any exported symbol
- for (Symbol *Sym : Symtab->getSymbols())
- if (Sym->isExported())
- Enqueue(Sym);
-
- // The ctor functions are all used in the synthetic __wasm_call_ctors
- // function, but since this function is created in-place it doesn't contain
- // relocations which mean we have to manually mark the ctors.
- for (const ObjFile *Obj : Symtab->ObjectFiles) {
- const WasmLinkingData &L = Obj->getWasmObj()->linkingData();
- for (const WasmInitFunc &F : L.InitFunctions)
- Enqueue(Obj->getFunctionSymbol(F.Symbol));
- }
-
- // Follow relocations to mark all reachable chunks.
- while (!Q.empty()) {
- InputChunk *C = Q.pop_back_val();
-
- for (const WasmRelocation Reloc : C->getRelocations()) {
- if (Reloc.Type == R_WEBASSEMBLY_TYPE_INDEX_LEB)
- continue;
- Symbol *Sym = C->File->getSymbol(Reloc.Index);
-
- // If the function has been assigned the special index zero in the table,
- // the relocation doesn't pull in the function body, since the function
- // won't actually go in the table (the runtime will trap attempts to call
- // that index, since we don't use it). A function with a table index of
- // zero is only reachable via "call", not via "call_indirect". The stub
- // functions used for weak-undefined symbols have this behaviour (compare
- // equal to null pointer, only reachable via direct call).
- if (Reloc.Type == R_WEBASSEMBLY_TABLE_INDEX_SLEB ||
- Reloc.Type == R_WEBASSEMBLY_TABLE_INDEX_I32) {
- FunctionSymbol *FuncSym = cast<FunctionSymbol>(Sym);
- if (FuncSym->hasTableIndex() && FuncSym->getTableIndex() == 0)
- continue;
- }
-
- Enqueue(Sym);
- }
- }
-
- // Report garbage-collected sections.
- if (Config->PrintGcSections) {
- for (const ObjFile *Obj : Symtab->ObjectFiles) {
- for (InputChunk *C : Obj->Functions)
- if (!C->Live)
- message("removing unused section " + toString(C));
- for (InputChunk *C : Obj->Segments)
- if (!C->Live)
- message("removing unused section " + toString(C));
- for (InputGlobal *G : Obj->Globals)
- if (!G->Live)
- message("removing unused section " + toString(G));
- for (InputEvent *E : Obj->Events)
- if (!E->Live)
- message("removing unused section " + toString(E));
- }
- for (InputChunk *C : Symtab->SyntheticFunctions)
- if (!C->Live)
- message("removing unused section " + toString(C));
- for (InputGlobal *G : Symtab->SyntheticGlobals)
- if (!G->Live)
- message("removing unused section " + toString(G));
- }
-}