[SPARC] Repair GOT references to internal symbols.

They had been getting emitted as a section + offset reference, which
is bogus since the value needs to be the offset within the GOT, not
the actual address of the symbol's object.

Differential Revision: http://reviews.llvm.org/D10441

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240020 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/ELFRelocs/Sparc.def

@@ -83,7 +83,7 @@ ELF_RELOC(R_SPARC_TLS_DTPOFF64,   77)
 ELF_RELOC(R_SPARC_TLS_TPOFF32,    78)
 ELF_RELOC(R_SPARC_TLS_TPOFF64,    79)
 ELF_RELOC(R_SPARC_GOTDATA_HIX22,  80)
-ELF_RELOC(R_SPARC_GOTDATA_LOX22,  81)
+ELF_RELOC(R_SPARC_GOTDATA_LOX10,  81)
 ELF_RELOC(R_SPARC_GOTDATA_OP_HIX22,  82)
-ELF_RELOC(R_SPARC_GOTDATA_OP_LOX22,  83)
+ELF_RELOC(R_SPARC_GOTDATA_OP_LOX10,  83)
 ELF_RELOC(R_SPARC_GOTDATA_OP,     84)

lib/Target/Sparc/AsmParser/SparcAsmParser.cpp

@@ -947,6 +947,8 @@ bool SparcAsmParser::matchRegisterName(const AsmToken &Tok,
   return false;
 }
 
+// Determine if an expression contains a reference to the symbol
+// "_GLOBAL_OFFSET_TABLE_".
 static bool hasGOTReference(const MCExpr *Expr) {
   switch (Expr->getKind()) {
   case MCExpr::Target:
@@ -998,6 +1000,13 @@ bool SparcAsmParser::matchSparcAsmModifiers(const MCExpr *&EVal,
 
   bool isPIC = getContext().getObjectFileInfo()->getRelocM() == Reloc::PIC_;
 
+  // Ugly: if a sparc assembly expression says "%hi(...)" but the
+  // expression within contains _GLOBAL_OFFSET_TABLE_, it REALLY means
+  // %pc22. Same with %lo -> %pc10. Worse, if it doesn't contain that,
+  // the meaning depends on whether the assembler was invoked with
+  // -KPIC or not: if so, it really means %got22/%got10; if not, it
+  // actually means what it said! Sigh, historical mistakes...
+
   switch(VK) {
   default: break;
   case SparcMCExpr::VK_Sparc_LO:

lib/Target/Sparc/MCTargetDesc/SparcELFObjectWriter.cpp

@@ -31,6 +31,10 @@ namespace {
   protected:
     unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
                           bool IsPCRel) const override;
+
+    bool needsRelocateWithSymbol(const MCSymbol &Sym,
+                                 unsigned Type) const override;
+
   };
 }
 
@@ -105,6 +109,27 @@ unsigned SparcELFObjectWriter::GetRelocType(const MCValue &Target,
   return ELF::R_SPARC_NONE;
 }
 
+bool SparcELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
+                                                 unsigned Type) const {
+  switch (Type) {
+    default:
+      return false;
+
+    // All relocations that use a GOT need a symbol, not an offset, as
+    // the offset of the symbol within the section is irrelevant to
+    // where the GOT entry is. Don't need to list all the TLS entries,
+    // as they're all marked as requiring a symbol anyways.
+    case ELF::R_SPARC_GOT10:
+    case ELF::R_SPARC_GOT13:
+    case ELF::R_SPARC_GOT22:
+    case ELF::R_SPARC_GOTDATA_HIX22:
+    case ELF::R_SPARC_GOTDATA_LOX10:
+    case ELF::R_SPARC_GOTDATA_OP_HIX22:
+    case ELF::R_SPARC_GOTDATA_OP_LOX10:
+      return true;
+  }
+}
+
 MCObjectWriter *llvm::createSparcELFObjectWriter(raw_pwrite_stream &OS,
                                                  bool Is64Bit,
                                                  bool IsLittleEndian,

test/CodeGen/SPARC/obj-relocs.ll

@@ -3,29 +3,35 @@
 
 ;CHECK-ABS:      Relocations [
 ;CHECK-ABS:         0x{{[0-9,A-F]+}} R_SPARC_H44 AGlobalVar 0x0
-;CHECK-ABS:    0x{{[0-9,A-F]+}} R_SPARC_M44 AGlobalVar 0x0
+;CHECK-ABS-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_M44 AGlobalVar 0x0
-;CHECK-ABS:    0x{{[0-9,A-F]+}} R_SPARC_L44 AGlobalVar 0x0
+;CHECK-ABS-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_L44 AGlobalVar 0x0
-;CHECK-ABS:    0x{{[0-9,A-F]+}} R_SPARC_WDISP30 bar 0x0
+;CHECK-ABS-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_H44 .rodata.str1.1 0x0
+;CHECK-ABS-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_M44 .rodata.str1.1 0x0
+;CHECK-ABS-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_WDISP30 bar 0x0
+;CHECK-ABS-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_L44 .rodata.str1.1 0x0
 ;CHECK-ABS:      ]
 
 ; CHECK-PIC:      Relocations [
 ; CHECK-PIC:         0x{{[0-9,A-F]+}} R_SPARC_PC22 _GLOBAL_OFFSET_TABLE_ 0x4
-; CHECK-PIC:    0x{{[0-9,A-F]+}} R_SPARC_PC10 _GLOBAL_OFFSET_TABLE_ 0x8
+; CHECK-PIC-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_PC10 _GLOBAL_OFFSET_TABLE_ 0x8
-; CHECK-PIC:    0x{{[0-9,A-F]+}} R_SPARC_GOT22 AGlobalVar 0x0
+; CHECK-PIC-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_GOT22 AGlobalVar 0x0
-; CHECK-PIC:    0x{{[0-9,A-F]+}} R_SPARC_GOT10 AGlobalVar 0x0
+; CHECK-PIC-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_GOT10 AGlobalVar 0x0
-; CHECK-PIC:    0x{{[0-9,A-F]+}} R_SPARC_WPLT30 bar 0x0
+; CHECK-PIC-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_GOT22 .L.mystr 0x0
+; CHECK-PIC-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_GOT10 .L.mystr 0x0
+; CHECK-PIC-NEXT:    0x{{[0-9,A-F]+}} R_SPARC_WPLT30 bar 0x0
 ; CHECK-PIC:      ]
 
 
 @AGlobalVar = global i64 0, align 8
+@.mystr = private unnamed_addr constant [6 x i8] c"hello\00", align 1
 
 define i64 @foo(i64 %a) {
 entry:
   %0 = load i64, i64* @AGlobalVar, align 4
   %1 = add i64 %a, %0
-  %2 = call i64 @bar(i64 %1)
+  %2 = call i64 @bar(i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.mystr, i32 0, i32 0), i64 %1)
   ret i64 %2
 }
 
 
-declare i64 @bar(i64)
+declare i64 @bar(i8*, i64)

test/MC/Sparc/sparc-pic.s

@@ -7,9 +7,16 @@
 ! CHECK-NEXT:   0x{{[0-9,A-F]+}} R_SPARC_PC10 _GLOBAL_OFFSET_TABLE_ 0x8
 ! CHECK-NEXT:   0x{{[0-9,A-F]+}} R_SPARC_GOT22 AGlobalVar 0x0
 ! CHECK-NEXT:   0x{{[0-9,A-F]+}} R_SPARC_GOT10 AGlobalVar 0x0
+! CHECK-NEXT:   0x{{[0-9,A-F]+}} R_SPARC_GOT22 .LC0 0x0
+! CHECK-NEXT:   0x{{[0-9,A-F]+}} R_SPARC_GOT10 .LC0 0x0
 ! CHECK-NEXT:   0x{{[0-9,A-F]+}} R_SPARC_WPLT30 bar 0x0
 ! CHECK:      ]
 
+        .section        ".rodata"
+        .align 8
+.LC0:
+        .asciz   "string"
+        .section ".text"
         .text
         .globl  foo
         .align  4
@@ -29,8 +36,11 @@ foo:
         add %i1, %o7, %i1
         sethi %hi(AGlobalVar), %i2
         add %i2, %lo(AGlobalVar), %i2
-        ldx [%i1+%i2], %i1
+        ldx [%i1+%i2], %i3
-        ldx [%i1], %i1
+        ldx [%i3], %i3
+        sethi %hi(.LC0), %i2
+        add %i2, %lo(.LC0), %i2
+        ldx [%i1+%i2], %i4
         call bar
         add %i0, %i1, %o0
         ret
@@ -46,4 +56,3 @@ foo:
 AGlobalVar:
         .xword  0                       ! 0x0
         .size   AGlobalVar, 8
-