[PATCH] D16925: [mips] Support LA expansion in PIC mode

[Srdjan Obucina via llvm-commits]

obucina updated this revision to Diff 47453.
obucina added a comment.

We couldn't extend test/MC/Mips/macro-la.s because some tests in it failed in pic mode. For example, 'la $5, symbol+8' gives: 'LLVM ERROR: unsupported reloc value'. Also, istruction la in the case 'la $5, 1f' does not expand properly because symbol 1 is defined at the end of the test file, so condition 'Sym->isInSection()' fails because of one pass structure of assembler.


http://reviews.llvm.org/D16925

Files:
  lib/Target/Mips/AsmParser/MipsAsmParser.cpp
  test/MC/Mips/la.pic.s

Index: test/MC/Mips/la.pic.s
===================================================================
--- test/MC/Mips/la.pic.s
+++ test/MC/Mips/la.pic.s
@@ -0,0 +1,29 @@
+# RUN: llvm-mc  %s -triple=mipsel-unknown-linux -mcpu=mips32 -show-encoding -relocation-model=pic | FileCheck %s -check-prefix=CHECK-PIC
+
+la $5, symbol         # CHECK-PIC: lw $5, %got(symbol)($gp)        # encoding: [A,A,0x85,0x8f]
+                      # CHECK-PIC:                                 # fixup A - offset: 0, value: symbol at GOT, kind: fixup_Mips_GOT_Local
+la $5, symbol($6)     # CHECK-PIC: lw $5, %got(symbol)($gp)        # encoding: [A,A,0x85,0x8f]
+                      # CHECK-PIC:                                 # fixup A - offset: 0, value: symbol at GOT, kind: fixup_Mips_GOT_Local
+                      # CHECK-PIC: addu    $5, $5, $6              # encoding: [0x21,0x28,0xa6,0x00]
+la $6, symbol($6)     # CHECK-PIC: lw      $1, %got(symbol)($gp)   # encoding: [A,A,0x81,0x8f]
+                      # CHECK-PIC:                                 # fixup A - offset: 0, value: symbol at GOT, kind: fixup_Mips_GOT_Local
+                      # CHECK-PIC: addu    $6, $1, $6              # encoding: [0x21,0x30,0x26,0x00]
+la $4, foo
+                      # CHECK-PIC: lw      $4, %got(foo)($gp)      # encoding: [A,A,0x84,0x8f]
+                      # CHECK-PIC:                                 # fixup A - offset: 0, value: foo at GOT, kind: fixup_Mips_GOT_Local
+dl:
+la $5,
+                      # CHECK-PIC: lw      $5, %got(dl)($gp)       # encoding: [A,A,0x85,0x8f]
+                      # CHECK-PIC:                                 # fixup A - offset: 0, value: dl at GOT, kind: fixup_Mips_GOT_Local
+                      # CHECK-PIC: addiu   $5, $5, %lo(dl)         # encoding: [A,A,0xa5,0x24]
+                      # CHECK-PIC:                                 # fixup A - offset: 0, value: %lo(dl), kind: fixup_Mips_LO16
+.globl  dg
+dg:
+la $5, dg
+                      # CHECK-PIC: lw      $5, %got(dg)($gp)       # encoding: [A,A,0x85,0x8f]
+                      # CHECK-PIC:                                 # fixup A - offset: 0, value: dg at GOT, kind: fixup_Mips_GOT_Local
+                      # CHECK-PIC: addiu   $5, $5, %lo(dg)         # encoding: [A,A,0xa5,0x24]
+                      # CHECK-PIC:                                 # fixup A - offset: 0, value: %lo(dg), kind: fixup_Mips_LO16
+
+
+
Index: lib/Target/Mips/AsmParser/MipsAsmParser.cpp
===================================================================
--- lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -2476,10 +2476,22 @@
     TmpReg = ATReg;
   }
 
-  emitRX(Mips::LUi, TmpReg, MCOperand::createExpr(HiExpr), IDLoc, Instructions);
-  emitRRX(Mips::ADDiu, TmpReg, TmpReg, MCOperand::createExpr(LoExpr), IDLoc,
-          Instructions);
-
+  const MCSymbol *Sym = getSingleMCSymbol(SymExpr);
+
+  if (inPicMode()) {
+    const MCExpr *Got16RelocExpr = evaluateRelocExpr(SymExpr, "got");
+    emitRRX(Mips::LW, TmpReg, Mips::GP, MCOperand::createExpr(Got16RelocExpr),
+            IDLoc, Instructions);
+    if(Sym->isInSection() && !Sym->isExternal())
+       emitRRX(Mips::ADDiu, TmpReg, TmpReg, MCOperand::createExpr(LoExpr),
+               IDLoc, Instructions);
+  } else {
+    emitRX(Mips::LUi, TmpReg, MCOperand::createExpr(HiExpr), IDLoc,
+           Instructions);
+    emitRRX(Mips::ADDiu, TmpReg, TmpReg, MCOperand::createExpr(LoExpr), IDLoc,
+            Instructions);
+  }
+
   if (UseSrcReg)
     emitRRR(Mips::ADDu, DstReg, TmpReg, SrcReg, IDLoc, Instructions);
   else


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