[LLD] Remove global state in lld/COFF

Remove globals from the lldCOFF library, by moving globals into a context class.
This patch mostly moves the config object into COFFLinkerContext.

See https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html for
context about removing globals from LLD.

Reviewed By: aganea

Differential Revision: https://reviews.llvm.org/D110450

lld/COFF/COFFLinkerContext.cpp

@@ -10,13 +10,15 @@
 //===----------------------------------------------------------------------===//
 
 #include "COFFLinkerContext.h"
+#include "Symbols.h"
 #include "lld/Common/Memory.h"
+#include "llvm/BinaryFormat/COFF.h"
 #include "llvm/DebugInfo/CodeView/TypeHashing.h"
+#include "llvm/Demangle/Demangle.h"
 
 namespace lld::coff {
-
 COFFLinkerContext::COFFLinkerContext()
-    : symtab(*this), rootTimer("Total Linking Time"),
+    : driver(*this), symtab(*this), rootTimer("Total Linking Time"),
       inputFileTimer("Input File Reading", rootTimer),
       ltoTimer("LTO", rootTimer), gcTimer("GC", rootTimer),
       icfTimer("ICF", rootTimer), codeLayoutTimer("Code Layout", rootTimer),
@@ -33,6 +35,10 @@ COFFLinkerContext::COFFLinkerContext()
       symbolMergingTimer("Symbol Merging", addObjectsTimer),
       publicsLayoutTimer("Publics Stream Layout", totalPdbLinkTimer),
       tpiStreamLayoutTimer("TPI Stream Layout", totalPdbLinkTimer),
-      diskCommitTimer("Commit to Disk", totalPdbLinkTimer) {}
-
+      diskCommitTimer("Commit to Disk", totalPdbLinkTimer) {
+  FakeSection ltoTextSection(llvm::COFF::IMAGE_SCN_MEM_EXECUTE);
+  FakeSection ltoDataSection(llvm::COFF::IMAGE_SCN_CNT_INITIALIZED_DATA);
+  ltoTextSectionChunk = make<FakeSectionChunk>(&ltoTextSection.section);
+  ltoDataSectionChunk = make<FakeSectionChunk>(&ltoDataSection.section);
+}
 } // namespace lld::coff

lld/COFF/COFFLinkerContext.h

@@ -6,12 +6,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLD_COFF_COFFLinkerContext_H
-#define LLD_COFF_COFFLinkerContext_H
+#ifndef LLD_COFF_COFFLINKERCONTEXT_H
+#define LLD_COFF_COFFLINKERCONTEXT_H
 
 #include "Chunks.h"
 #include "Config.h"
 #include "DebugTypes.h"
+#include "Driver.h"
 #include "InputFiles.h"
 #include "SymbolTable.h"
 #include "Writer.h"
@@ -27,9 +28,9 @@ class COFFLinkerContext : public CommonLinkerContext {
   COFFLinkerContext &operator=(const COFFLinkerContext &) = delete;
   ~COFFLinkerContext() = default;
 
-  void addTpiSource(TpiSource *tpi) { tpiSourceList.push_back(tpi); }
-
+  LinkerDriver driver;
   SymbolTable symtab;
+  COFFOptTable optTable;
 
   std::vector<ObjFile *> objFileInstances;
   std::map<std::string, PDBInputFile *> pdbInputFileInstances;
@@ -41,6 +42,8 @@ class COFFLinkerContext : public CommonLinkerContext {
   /// All sources of type information in the program.
   std::vector<TpiSource *> tpiSourceList;
 
+  void addTpiSource(TpiSource *tpi) { tpiSourceList.push_back(tpi); }
+
   std::map<llvm::codeview::GUID, TpiSource *> typeServerSourceMappings;
   std::map<uint32_t, TpiSource *> precompSourceMappings;
 
@@ -52,6 +55,10 @@ class COFFLinkerContext : public CommonLinkerContext {
     return c->osidx == 0 ? nullptr : outputSections[c->osidx - 1];
   }
 
+  // Fake sections for parsing bitcode files.
+  FakeSectionChunk *ltoTextSectionChunk;
+  FakeSectionChunk *ltoDataSectionChunk;
+
   // All timers used in the COFF linker.
   Timer rootTimer;
   Timer inputFileTimer;
@@ -77,6 +84,8 @@ class COFFLinkerContext : public CommonLinkerContext {
   Timer publicsLayoutTimer;
   Timer tpiStreamLayoutTimer;
   Timer diskCommitTimer;
+
+  Configuration config;
 };
 
 } // namespace lld::coff

lld/COFF/CallGraphSort.cpp

@@ -56,6 +56,8 @@ class CallGraphSort {
 private:
   std::vector<Cluster> clusters;
   std::vector<const SectionChunk *> sections;
+
+  const COFFLinkerContext &ctx;
 };
 
 // Maximum amount the combined cluster density can be worse than the original
@@ -71,8 +73,8 @@ using SectionPair = std::pair<const SectionChunk *, const SectionChunk *>;
 // Take the edge list in Config->CallGraphProfile, resolve symbol names to
 // Symbols, and generate a graph between InputSections with the provided
 // weights.
-CallGraphSort::CallGraphSort(const COFFLinkerContext &ctx) {
-  MapVector<SectionPair, uint64_t> &profile = config->callGraphProfile;
+CallGraphSort::CallGraphSort(const COFFLinkerContext &ctx) : ctx(ctx) {
+  const MapVector<SectionPair, uint64_t> &profile = ctx.config.callGraphProfile;
   DenseMap<const SectionChunk *, int> secToCluster;
 
   auto getOrCreateNode = [&](const SectionChunk *isec) -> int {
@@ -85,7 +87,7 @@ CallGraphSort::CallGraphSort(const COFFLinkerContext &ctx) {
   };
 
   // Create the graph.
-  for (std::pair<SectionPair, uint64_t> &c : profile) {
+  for (const std::pair<SectionPair, uint64_t> &c : profile) {
     const auto *fromSec = cast<SectionChunk>(c.first.first->repl);
     const auto *toSec = cast<SectionChunk>(c.first.second->repl);
     uint64_t weight = c.second;
@@ -205,11 +207,11 @@ DenseMap<const SectionChunk *, int> CallGraphSort::run() {
         break;
     }
   }
-  if (!config->printSymbolOrder.empty()) {
+  if (!ctx.config.printSymbolOrder.empty()) {
     std::error_code ec;
-    raw_fd_ostream os(config->printSymbolOrder, ec, sys::fs::OF_None);
+    raw_fd_ostream os(ctx.config.printSymbolOrder, ec, sys::fs::OF_None);
     if (ec) {
-      error("cannot open " + config->printSymbolOrder + ": " + ec.message());
+      error("cannot open " + ctx.config.printSymbolOrder + ": " + ec.message());
       return orderMap;
     }
     // Print the symbols ordered by C3, in the order of increasing curOrder