[AIX] Make sure to use QualNames for external global objects

[daltenty]

Summary

Previously we only handled the case where the csect hadn't been set up yet, so we'd hit an assert later on.

[hubert.reinterpretcast]

llvm/test/CodeGen/PowerPC/aix-xcoff-toc.ll

31

This needs a comment to explain why a second function is useful for the test. The fact that this tests for a bug that need not have existed is non-obvious.

86

It is possible to use an expression here that is based on the value observed for the TOC base? Similarly for the lines below.

[daltenty]

llvm/test/CodeGen/PowerPC/aix-xcoff-toc.ll

86

I believe doing so is dependent on the hex format support under review in D60389

[jasonliu]

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

1897

nit: This return statement is like a short cut, maybe we could remove it to make this if block simpler?

[daltenty]

• Add comment

[daltenty]

• Remove redundant return

[jasonliu]

LGTM with minor nit.

llvm/test/CodeGen/PowerPC/aix-xcoff-toc.ll

31

Suggestion for comment:
Reference external globals again to make sure setting up csect for external global is properly guarded.

[hubert.reinterpretcast]

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

1888

How do we know that having the containing csect set is enough to know that the storage class has been set? Should we have an assume after the if block that the storage class is set? Or perhaps a comment that the containing csect could not have been set without the storage class being set on the symbol.

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

PPCAIXAsmPrinter::getMCSymbolForTOCPseudoMO(const MachineOperand &MO) {
   }
 
   MCSymbolXCOFF *XSym = cast<MCSymbolXCOFF>(getSymbol(GO));
 
   // If the global object is a global variable without initializer or is a
   // declaration of a function, then XSym is an external referenced symbol.
   // Hence we may need to explictly create a MCSectionXCOFF for it so that we
   // can return its symbol later.
-  if (GO->isDeclaration() && !XSym->hasContainingCsect()) {
+  if (GO->isDeclaration()) {
+    if (!XSym->hasContainingCsect()) {
       // Make sure the storage class is set.
       const XCOFF::StorageClass SC =
           TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(GO);
       XSym->setStorageClass(SC);
 
       MCSectionXCOFF *Csect = OutStreamer->getContext().getXCOFFSection(
           XSym->getName(), isa<Function>(GO) ? XCOFF::XMC_DS : XCOFF::XMC_UA,
           XCOFF::XTY_ER, SC, SectionKind::getMetadata());
       XSym->setContainingCsect(Csect);
+    }
 
-    return Csect->getQualNameSymbol();
+    return XSym->getContainingCsect()->getQualNameSymbol();
   }
 
   // Handle initialized global variables.
   if (GV) {
     SectionKind GVKind = getObjFileLowering().getKindForGlobal(GV, TM);
 
     // If the operand is a common then we should refer to the csect symbol.
     if (GVKind.isCommon() || GVKind.isBSSLocal()) {

llvm/test/CodeGen/PowerPC/aix-xcoff-toc.ll

define void @bar() {
   store i64 0, i64* @b, align 8
   store i16 0, i16* @c, align 2
   store i32 0, i32* @globa, align 4
   store void (...)* bitcast (void ()* @bar to void (...)*), void (...)** @ptr, align 4
   store i8* bitcast (void ()* @foo to i8*), i8** %1, align 8
   ret void
 }
 
+; We initialize a csect when we first reference an external global, so make sure we don't run into problems when we see it again.
+define void @bar2() {
+  store i32 0, i32* @a, align 4
+  store i64 0, i64* @b, align 8
+  store i16 0, i16* @c, align 2
+  ret void
+}
+
 ; CHECK-NOT: .comm a
 ; CHECK-NOT: .lcomm a
 ; CHECK-NOT: .comm b
 ; CHECK-NOT: .lcomm b
 ; CHECK-NOT: .comm c
 ; CHECK-NOT: .lcomm c
 ; CHECK: .comm globa[RW],4,2
 ; CHECK32: .lcomm ptr,4,ptr[BS],2

 ; CHECK-NEXT: .tc   ptr[TC],ptr[BS]
 ; CHECK-NEXT: LC5:
 ; CHECK-NEXT: .tc   bar[TC],bar[DS]
 ; CHECK-NEXT: LC6:
 ; CHECK-NEXT: .tc   foo[TC],foo[DS]
 
 ; SYM:       File: {{.*}}aix-xcoff-toc.ll.tmp.o
 ; SYM:       Symbol {{[{][[:space:]] *}}Index: [[#INDX:]]{{[[:space:]] *}}Name: TOC
-; SYM-NEXT:    Value (RelocatableAddress): 0x54
+; SYM-NEXT:    Value (RelocatableAddress): 0x8C
 ; SYM-NEXT:    Section: .data
 ; SYM-NEXT:    Type: 0x0
 ; SYM-NEXT:    StorageClass: C_HIDEXT (0x6B)
 ; SYM-NEXT:    NumberOfAuxEntries: 1
 ; SYM-NEXT:    CSECT Auxiliary Entry {
 ; SYM-NEXT:      Index: [[#INDX+1]]
 ; SYM-NEXT:      SectionLen: 0
 ; SYM-NEXT:      ParameterHashIndex: 0x0
 ; SYM-NEXT:      TypeChkSectNum: 0x0
 ; SYM-NEXT:      SymbolAlignmentLog2: 2
 ; SYM-NEXT:      SymbolType: XTY_SD (0x1)
 ; SYM-NEXT:      StorageMappingClass: XMC_TC0 (0xF)
 ; SYM-NEXT:      StabInfoIndex: 0x0
 ; SYM-NEXT:      StabSectNum: 0x0
 ; SYM-NEXT:    }
 ; SYM-NEXT:  }
 ; SYM-NEXT:  Symbol {
 ; SYM-NEXT:    Index: [[#INDX+2]]
 ; SYM-NEXT:    Name: a
-; SYM-NEXT:    Value (RelocatableAddress): 0x54
+; SYM-NEXT:    Value (RelocatableAddress): 0x8C
 ; SYM-NEXT:    Section: .data
 ; SYM-NEXT:    Type: 0x0
 ; SYM-NEXT:    StorageClass: C_HIDEXT (0x6B)
 ; SYM-NEXT:    NumberOfAuxEntries: 1
 ; SYM-NEXT:    CSECT Auxiliary Entry {
 ; SYM-NEXT:      Index: [[#INDX+3]]
 ; SYM-NEXT:      SectionLen: 4
 ; SYM-NEXT:      ParameterHashIndex: 0x0
 ; SYM-NEXT:      TypeChkSectNum: 0x0
 ; SYM-NEXT:      SymbolAlignmentLog2: 2
 ; SYM-NEXT:      SymbolType: XTY_SD (0x1)
 ; SYM-NEXT:      StorageMappingClass: XMC_TC (0x3)
 ; SYM-NEXT:      StabInfoIndex: 0x0
 ; SYM-NEXT:      StabSectNum: 0x0
 ; SYM-NEXT:    }
 ; SYM-NEXT:  }
 ; SYM-NEXT:  Symbol {
 ; SYM-NEXT:    Index: [[#INDX+4]]
 ; SYM-NEXT:    Name: b
-; SYM-NEXT:    Value (RelocatableAddress): 0x58
+; SYM-NEXT:    Value (RelocatableAddress): 0x90
 ; SYM-NEXT:    Section: .data
 ; SYM-NEXT:    Type: 0x0
 ; SYM-NEXT:    StorageClass: C_HIDEXT (0x6B)
 ; SYM-NEXT:    NumberOfAuxEntries: 1
 ; SYM-NEXT:    CSECT Auxiliary Entry {
 ; SYM-NEXT:      Index: [[#INDX+5]]
 ; SYM-NEXT:      SectionLen: 4
 ; SYM-NEXT:      ParameterHashIndex: 0x0
 ; SYM-NEXT:      TypeChkSectNum: 0x0
 ; SYM-NEXT:      SymbolAlignmentLog2: 2
 ; SYM-NEXT:      SymbolType: XTY_SD (0x1)
 ; SYM-NEXT:      StorageMappingClass: XMC_TC (0x3)
 ; SYM-NEXT:      StabInfoIndex: 0x0
 ; SYM-NEXT:      StabSectNum: 0x0
 ; SYM-NEXT:    }
 ; SYM-NEXT:  }
 ; SYM-NEXT:  Symbol {
 ; SYM-NEXT:    Index: [[#INDX+6]]
 ; SYM-NEXT:    Name: c
-; SYM-NEXT:    Value (RelocatableAddress): 0x5C
+; SYM-NEXT:    Value (RelocatableAddress): 0x94
 ; SYM-NEXT:    Section: .data
 ; SYM-NEXT:    Type: 0x0
 ; SYM-NEXT:    StorageClass: C_HIDEXT (0x6B)
 ; SYM-NEXT:    NumberOfAuxEntries: 1
 ; SYM-NEXT:    CSECT Auxiliary Entry {
 ; SYM-NEXT:      Index: [[#INDX+7]]
 ; SYM-NEXT:      SectionLen: 4
 ; SYM-NEXT:      ParameterHashIndex: 0x0
 ; SYM-NEXT:      TypeChkSectNum: 0x0
 ; SYM-NEXT:      SymbolAlignmentLog2: 2
 ; SYM-NEXT:      SymbolType: XTY_SD (0x1)
 ; SYM-NEXT:      StorageMappingClass: XMC_TC (0x3)
 ; SYM-NEXT:      StabInfoIndex: 0x0
 ; SYM-NEXT:      StabSectNum: 0x0
 ; SYM-NEXT:    }
 ; SYM-NEXT:  }
 ; SYM-NEXT:  Symbol {
 ; SYM-NEXT:    Index: [[#INDX+8]]
 ; SYM-NEXT:    Name: globa
-; SYM-NEXT:    Value (RelocatableAddress): 0x60
+; SYM-NEXT:    Value (RelocatableAddress): 0x98
 ; SYM-NEXT:    Section: .data
 ; SYM-NEXT:    Type: 0x0
 ; SYM-NEXT:    StorageClass: C_HIDEXT (0x6B)
 ; SYM-NEXT:    NumberOfAuxEntries: 1
 ; SYM-NEXT:    CSECT Auxiliary Entry {
 ; SYM-NEXT:      Index: [[#INDX+9]]
 ; SYM-NEXT:      SectionLen: 4
 ; SYM-NEXT:      ParameterHashIndex: 0x0
 ; SYM-NEXT:      TypeChkSectNum: 0x0
 ; SYM-NEXT:      SymbolAlignmentLog2: 2
 ; SYM-NEXT:      SymbolType: XTY_SD (0x1)
 ; SYM-NEXT:      StorageMappingClass: XMC_TC (0x3)
 ; SYM-NEXT:      StabInfoIndex: 0x0
 ; SYM-NEXT:      StabSectNum: 0x0
 ; SYM-NEXT:    }
 ; SYM-NEXT:  }
 ; SYM-NEXT:  Symbol {
 ; SYM-NEXT:    Index: [[#INDX+10]]
 ; SYM-NEXT:    Name: ptr
-; SYM-NEXT:    Value (RelocatableAddress): 0x64
+; SYM-NEXT:    Value (RelocatableAddress): 0x9C
 ; SYM-NEXT:    Section: .data
 ; SYM-NEXT:    Type: 0x0
 ; SYM-NEXT:    StorageClass: C_HIDEXT (0x6B)
 ; SYM-NEXT:    NumberOfAuxEntries: 1
 ; SYM-NEXT:    CSECT Auxiliary Entry {
 ; SYM-NEXT:      Index: [[#INDX+11]]
 ; SYM-NEXT:      SectionLen: 4
 ; SYM-NEXT:      ParameterHashIndex: 0x0
 ; SYM-NEXT:      TypeChkSectNum: 0x0
 ; SYM-NEXT:      SymbolAlignmentLog2: 2
 ; SYM-NEXT:      SymbolType: XTY_SD (0x1)
 ; SYM-NEXT:      StorageMappingClass: XMC_TC (0x3)
 ; SYM-NEXT:      StabInfoIndex: 0x0
 ; SYM-NEXT:      StabSectNum: 0x0
 ; SYM-NEXT:    }
 ; SYM-NEXT:  }
 ; SYM-NEXT:  Symbol {
 ; SYM-NEXT:    Index: [[#INDX+12]]
 ; SYM-NEXT:    Name: bar
-; SYM-NEXT:    Value (RelocatableAddress): 0x68
+; SYM-NEXT:    Value (RelocatableAddress): 0xA0
 ; SYM-NEXT:    Section: .data
 ; SYM-NEXT:    Type: 0x0
 ; SYM-NEXT:    StorageClass: C_HIDEXT (0x6B)
 ; SYM-NEXT:    NumberOfAuxEntries: 1
 ; SYM-NEXT:    CSECT Auxiliary Entry {
 ; SYM-NEXT:      Index: [[#INDX+13]]
 ; SYM-NEXT:      SectionLen: 4
 ; SYM-NEXT:      ParameterHashIndex: 0x0
 ; SYM-NEXT:      TypeChkSectNum: 0x0
 ; SYM-NEXT:      SymbolAlignmentLog2: 2
 ; SYM-NEXT:      SymbolType: XTY_SD (0x1)
 ; SYM-NEXT:      StorageMappingClass: XMC_TC (0x3)
 ; SYM-NEXT:      StabInfoIndex: 0x0
 ; SYM-NEXT:      StabSectNum: 0x0
 ; SYM-NEXT:    }
 ; SYM-NEXT:  }
 ; SYM-NEXT:  Symbol {
 ; SYM-NEXT:    Index: [[#INDX+14]]
 ; SYM-NEXT:    Name: foo
-; SYM-NEXT:    Value (RelocatableAddress): 0x6C
+; SYM-NEXT:    Value (RelocatableAddress): 0xA4
 ; SYM-NEXT:    Section: .data
 ; SYM-NEXT:    Type: 0x0
 ; SYM-NEXT:    StorageClass: C_HIDEXT (0x6B)
 ; SYM-NEXT:    NumberOfAuxEntries: 1
 ; SYM-NEXT:    CSECT Auxiliary Entry {
 ; SYM-NEXT:      Index: [[#INDX+15]]
 ; SYM-NEXT:      SectionLen: 4
 ; SYM-NEXT:      ParameterHashIndex: 0x0
 ; SYM-NEXT:      TypeChkSectNum: 0x0
 ; SYM-NEXT:      SymbolAlignmentLog2: 2
 ; SYM-NEXT:      SymbolType: XTY_SD (0x1)
 ; SYM-NEXT:      StorageMappingClass: XMC_TC (0x3)
 ; SYM-NEXT:      StabInfoIndex: 0x0
 ; SYM-NEXT:      StabSectNum: 0x0
 ; SYM-NEXT:    }
 ; SYM-NEXT:  }