LTO: Reduce memory consumption by creating an in-memory symbol table for InputFiles. NFCI.

Introduce symbol table data structures that can be potentially written to
disk, have the LTO library build those data structures using temporarily
constructed modules and redirect the LTO library implementation to go through
those data structures. This allows us to remove the LLVMContext and Modules
owned by InputFile.

With this change I measured a peak memory consumption decrease from 5.4GB to
2.8GB in a no-op incremental ThinLTO link of Chromium on Linux. The impact on
memory consumption is larger in COFF linkers where we are currently forced
to materialize all metadata in order to read linker options. Peak memory
consumption linking a large piece of Chromium for Windows with full LTO and
debug info decreases from >64GB (OOM) to 15GB.

Part of PR27551.

Differential Revision: https://reviews.llvm.org/D31364

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299168 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 2 deletions

diff --git a/tools/gold/gold-plugin.cpp b/tools/gold/gold-plugin.cpp
index 8c3fa42981fe..9b783d19a283 100644
--- a/tools/gold/gold-plugin.cpp
+++ b/tools/gold/gold-plugin.cpp
@@ -465,7 +465,7 @@ static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
           EC == object::object_error::bitcode_section_not_found)
         *claimed = 0;
       else
-        message(LDPL_ERROR,
+        message(LDPL_FATAL,
                 "LLVM gold plugin has failed to create LTO module: %s",
                 EI.message().c_str());
     });
@@ -536,7 +536,7 @@ static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
 
     sym.size = 0;
     sym.comdat_key = nullptr;
-    int CI = check(Sym.getComdatIndex());
+    int CI = Sym.getComdatIndex();
     if (CI != -1) {
       StringRef C = Obj->getComdatTable()[CI];
       sym.comdat_key = strdup(C.str().c_str());