[MC][ELF] fix newly added test

[nickdesaulniers]

Summary

Reland of

• r344197 "[MC][ELF] compute entity size for explicit sections"
• r344206 "[MC][ELF] Fix section_mergeable_size.ll"

after being reverted in r344278 due to build breakages from not
specifying a target triple.

Move test from test/CodeGen/Generic/ to test/MC/ELF/.
Add explicit target triple so we don't try to run
this test on non ELF targets.

Reported: https://reviews.llvm.org/D53056#1261707

[rengolin]

The failure in Arm had nothing to do with not being ELF, but the asm syntax was different.

.init.rodata,"aM",%progbits,4

instead of

.init.rodata,"aM",@progbits,4

A CHECK line like:

.init.rodata,"aM",{{.}}progbits,4

would probably work.

[rengolin]

Oh, you've done that. The diff isn't clear.

Also, I don't think CodeGen/Generic is the right place. Why can't you just leave in MC/ELF with the new CHECK line?

[nickdesaulniers]

but the asm syntax was different
Oh, you've done that. The diff isn't clear.

@MaskRay fixed this mistake of mine in r344206.

I don't think CodeGen/Generic is the right place. Why can't you just leave in MC/ELF with the new CHECK line?

I agree; note that phabricator has funny UI for a moved file that was then modified. Triple check the direction of the arrows (-->, <--); note how they flip for the modification.

[NoQ]

I reverted rL344197 and rL344206 in rL344278 because buildbots kept failing and it sounds like you're still discussing the details of how to fix this. Let's try to not keep buildbots red for more than a couple of hours because it masks other people's failures and quickly snowballs. Thx! And sry if you were actually about to commit the fix.

[nickdesaulniers]

• reland r344197

[rnk]

test/MC/ELF/section_mergeable_size.ll

1 ↗

(On Diff #169286)

This is an LLC test testing an implementation detail of lib/CodeGen/TargetLoweringObjectFile.cpp, which is not part of MC. It should probably be in llvm/test/CodeGen/X86.

[nickdesaulniers]

• move test from test/MC/ELF/ to test/CodeGen/X86/

[rnk]

lgtm

[nickdesaulniers]

Thanks @rnk for the review, @NoQ for the quick revert (I agree with the quick revert, clean landing policy). @fhahn can you test this for me on OSX to triple check? Any additional code review @rengolin ?

[fhahn]

In D53146#1262606, @nickdesaulniers wrote:

Thanks @rnk for the review, @NoQ for the quick revert (I agree with the quick revert, clean landing policy). @fhahn can you test this for me on OSX to triple check? Any additional code review @rengolin ?

This should be fine now, with the -linux- triple

llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

static const MCSymbolELF *getAssociatedSymbol(const GlobalObject *GO,
   auto *VM = dyn_cast<ValueAsMetadata>(Op);
   if (!VM)
     report_fatal_error("MD_associated operand is not ValueAsMetadata");
 
   GlobalObject *OtherGO = dyn_cast<GlobalObject>(VM->getValue());
   return OtherGO ? dyn_cast<MCSymbolELF>(TM.getSymbol(OtherGO)) : nullptr;
 }
 
+static unsigned getEntrySizeForKind(SectionKind Kind) {
+  if (Kind.isMergeable1ByteCString())
+    return 1;
+  else if (Kind.isMergeable2ByteCString())
+    return 2;
+  else if (Kind.isMergeable4ByteCString())
+    return 4;
+  else if (Kind.isMergeableConst4())
+    return 4;
+  else if (Kind.isMergeableConst8())
+    return 8;
+  else if (Kind.isMergeableConst16())
+    return 16;
+  else if (Kind.isMergeableConst32())
+    return 32;
+  else {
+    // We shouldn't have mergeable C strings or mergeable constants that we
+    // didn't handle above.
+    assert(!Kind.isMergeableCString() && "unknown string width");
+    assert(!Kind.isMergeableConst() && "unknown data width");
+    return 0;
+  }
+}
+
 MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal(
     const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
   StringRef SectionName = GO->getSection();
 
   // Check if '#pragma clang section' name is applicable.
   // Note that pragma directive overrides -ffunction-section, -fdata-section
   // and so section name is exactly as user specified and not uniqued.
   const GlobalVariable *GV = dyn_cast<GlobalVariable>(GO);
MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal(
   const MCSymbolELF *AssociatedSymbol = getAssociatedSymbol(GO, TM);
   if (AssociatedSymbol) {
     UniqueID = NextUniqueID++;
     Flags |= ELF::SHF_LINK_ORDER;
   }
 
   MCSectionELF *Section = getContext().getELFSection(
       SectionName, getELFSectionType(SectionName, Kind), Flags,
-      /*EntrySize=*/0, Group, UniqueID, AssociatedSymbol);
+      getEntrySizeForKind(Kind), Group, UniqueID, AssociatedSymbol);
   // Make sure that we did not get some other section with incompatible sh_link.
   // This should not be possible due to UniqueID code above.
   assert(Section->getAssociatedSymbol() == AssociatedSymbol &&
          "Associated symbol mismatch between sections");
   return Section;
 }
 
 /// Return the section prefix name used by options FunctionsSections and
static StringRef getSectionPrefixForGlobal(SectionKind Kind) {
   if (Kind.isThreadBSS())
     return ".tbss";
   if (Kind.isData())
     return ".data";
   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
   return ".data.rel.ro";
 }
 
-static unsigned getEntrySizeForKind(SectionKind Kind) {
-  if (Kind.isMergeable1ByteCString())
-    return 1;
-  else if (Kind.isMergeable2ByteCString())
-    return 2;
-  else if (Kind.isMergeable4ByteCString())
-    return 4;
-  else if (Kind.isMergeableConst4())
-    return 4;
-  else if (Kind.isMergeableConst8())
-    return 8;
-  else if (Kind.isMergeableConst16())
-    return 16;
-  else if (Kind.isMergeableConst32())
-    return 32;
-  else {
-    // We shouldn't have mergeable C strings or mergeable constants that we
-    // didn't handle above.
-    assert(!Kind.isMergeableCString() && "unknown string width");
-    assert(!Kind.isMergeableConst() && "unknown data width");
-    return 0;
-  }
-}
-
 static MCSectionELF *selectELFSectionForGlobal(
     MCContext &Ctx, const GlobalObject *GO, SectionKind Kind, Mangler &Mang,
     const TargetMachine &TM, bool EmitUniqueSection, unsigned Flags,
     unsigned *NextUniqueID, const MCSymbolELF *AssociatedSymbol) {
 
   StringRef Group = "";
   if (const Comdat *C = getELFComdat(GO)) {
     Flags |= ELF::SHF_GROUP;

llvm/trunk/test/CodeGen/X86/section_mergeable_size.ll

+; RUN: llc -mtriple x86_64-linux-gnu < %s | FileCheck %s
+@a = internal unnamed_addr constant [1 x [1 x i32]] zeroinitializer, section ".init.rodata", align 4
+; CHECK: .init.rodata,"aM",{{[@%]}}progbits,4