[ThinLTO] Handle -fno-builtin* options for distributed backends

[tejohnson]

Summary

Without this patch, we were ignoring the -fno-builtin* options for clang
invocations performing ThinLTO distributed backends. Create and pass
down to LTO a TargetLibraryInfoImpl. A separate llvm-side patch will be
sent to add the new Config field and its necessary handling.

Depends on D60162.

[tejohnson]

ping

[tejohnson]

The parent revision now includes both clang and llvm side changes.

lib/CodeGen/BackendUtil.cpp

static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
   }
   Conf.CPU = TOpts.CPU;
   Conf.CodeModel = getCodeModel(CGOpts);
   Conf.MAttrs = TOpts.Features;
   Conf.RelocModel = CGOpts.RelocationModel;
   Conf.CGOptLevel = getCGOptLevel(CGOpts);
   initTargetOptions(Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
   Conf.SampleProfile = std::move(SampleProfile);
+  Triple TargetTriple(M->getTargetTriple());
+  std::unique_ptr<TargetLibraryInfoImpl> TLII(createTLII(TargetTriple, CGOpts));
+  Conf.TLII = std::move(TLII);
 
   // Context sensitive profile.
   if (CGOpts.hasProfileCSIRInstr()) {
     Conf.RunCSIRInstr = true;
     Conf.CSIRProfile = std::move(CGOpts.InstrProfileOutput);
   } else if (CGOpts.hasProfileCSIRUse()) {
     Conf.RunCSIRInstr = false;
     Conf.CSIRProfile = std::move(CGOpts.ProfileInstrumentUsePath);

test/CodeGen/thinlto_backend_nobuiltin.ll

+; Make sure that -fno-builtin* is passed down and handled properly in
+; the ThinLTO distributed backend.
+; REQUIRES: x86-registered-target
+
+; RUN: opt -module-summary -o %t.o %s
+; RUN: llvm-lto -thinlto -o %t %t.o
+
+; By default the optimizer will convert memset call to intinsic
+; RUN: %clang -target x86_64-unknown-linux-gnu -O2 -o %t2.o -x ir %t.o -c -fthinlto-index=%t.thinlto.bc -save-temps=obj
+; RUN: llvm-dis %t.s.4.opt.bc -o - | FileCheck %s --check-prefix=BUILTIN
+
+; With -fno-builtin-memset it should not
+; RUN: %clang -target x86_64-unknown-linux-gnu -O2 -o %t2.o -x ir %t.o -c -fthinlto-index=%t.thinlto.bc -save-temps=obj -fno-builtin-memset
+; RUN: llvm-dis %t.s.4.opt.bc -o - | FileCheck %s --check-prefix=NOBUILTIN
+
+; Similarly, with -fno-builtin it should not
+; RUN: %clang -target x86_64-unknown-linux-gnu -O2 -o %t2.o -x ir %t.o -c -fthinlto-index=%t.thinlto.bc -save-temps=obj -fno-builtin
+; RUN: llvm-dis %t.s.4.opt.bc -o - | FileCheck %s --check-prefix=NOBUILTIN
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare i8* @memset(i8*, i8, i64)
+
+define i8* @test(i8* %mem, i8 %val, i64 %size) {
+  ; BUILTIN: call void @llvm.memset.p0i8.i64
+  ; NOBUILTIN: call i8* @memset
+  %ret = call i8* @memset(i8* %mem, i8 %val, i64 %size)
+  ret i8* %ret
+}