[gn build] Remove unnecessary lld dependency on DebugInfo/Symbolize.

[noajshu]

Summary

The gn script for lld's COFF lib adds an unnecessary dependency on llvm/lib/DebugInfo/Symbolize. There is no such dependency in lld/COFF/CMakeLists.txt. This can be safely removed.

[phosek]

LGTM

[noajshu]

Replace include of Symbolize.h with DIContext.h in lld/COFF/SymbolTable.cpp. LLD just needs llvm/DebugInfo/DIContext.h which it currently gets through
Symbolize.h -> SymbolizableModule.h -> DIContext.h.
This needlessly pulls in extra headers (and perhaps led to the gn dep line fixed in this diff, although I'm not familiar with how the gn build is maintained.).

[noajshu]

Thanks for the review @phosek . Just to avoid any possible confusion I've also corrected SymbolTable.cpp to include "DIContext.h" instead of "Symbolize.h". Does this still LGTY?

[phosek]

In D115554#3186592, @noajshu wrote:

Thanks for the review @phosek . Just to avoid any possible confusion I've also corrected SymbolTable.cpp to include "DIContext.h" instead of "Symbolize.h". Does this still LGTY?

Can we do that in a separate change?

[thakis]

This change lg, looks like https://reviews.llvm.org/D69198 removed this dep.

[noajshu]

Removed change of Symbolize header include.

[noajshu]

In D115554#3188370, @phosek wrote:

In D115554#3186592, @noajshu wrote:

Thanks for the review @phosek . Just to avoid any possible confusion I've also corrected SymbolTable.cpp to include "DIContext.h" instead of "Symbolize.h". Does this still LGTY?

Can we do that in a separate change?

Sure! I've moved that change into D115659.

llvm/utils/gn/secondary/lld/COFF/BUILD.gn

static_library("COFF") {
   configs += [ "//llvm/utils/gn/build:lld_code" ]
   deps = [
     ":Options",
     "//lld/Common",
     "//llvm/lib/BinaryFormat",
     "//llvm/lib/DebugInfo/CodeView",
     "//llvm/lib/DebugInfo/MSF",
     "//llvm/lib/DebugInfo/PDB",
-    "//llvm/lib/DebugInfo/Symbolize",
     "//llvm/lib/IR",
     "//llvm/lib/LTO",
     "//llvm/lib/MC",
     "//llvm/lib/Object",
     "//llvm/lib/Option",
     "//llvm/lib/Support",
     "//llvm/lib/Target:TargetsToBuild",
     "//llvm/lib/ToolDrivers/llvm-lib:LibDriver",