[PowerPC] Support absolute branches

There is currently only limited support for the "absolute" variants
of branch instructions.  This patch adds support for the absolute
variants of all branches that are currently otherwise supported.

This requires adding new fixup types so that the correct variant
of relocation type can be selected by the object writer.

While the compiler will continue to usually choose the relative
branch variants, this will allow the asm parser to fully support
the absolute branches, with either immediate (numerical) or
symbolic target addresses.

No change in code generation intended.

llvm-svn: 184721

1 files changed, 14 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp b/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
index 6318d416f5e..999c6778248 100644
--- a/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
+++ b/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
@@ -267,6 +267,12 @@ public:
   bool isS16ImmX4() const { return Kind == Expression ||
                                    (Kind == Immediate && isInt<16>(getImm()) &&
                                     (getImm() & 3) == 0); }
+  bool isDirectBr() const { return Kind == Expression ||
+                                   (Kind == Immediate && isInt<26>(getImm()) &&
+                                    (getImm() & 3) == 0); }
+  bool isCondBr() const { return Kind == Expression ||
+                                 (Kind == Immediate && isInt<16>(getImm()) &&
+                                  (getImm() & 3) == 0); }
   bool isRegNumber() const { return Kind == Immediate && isUInt<5>(getImm()); }
   bool isCCRegNumber() const { return Kind == Immediate &&
                                       isUInt<3>(getImm()); }
@@ -351,6 +357,14 @@ public:
       Inst.addOperand(MCOperand::CreateExpr(getExpr()));
   }
 
+  void addBranchTargetOperands(MCInst &Inst, unsigned N) const {
+    assert(N == 1 && "Invalid number of operands!");
+    if (Kind == Immediate)
+      Inst.addOperand(MCOperand::CreateImm(getImm() / 4));
+    else
+      Inst.addOperand(MCOperand::CreateExpr(getExpr()));
+  }
+
   StringRef getToken() const {
     assert(Kind == Token && "Invalid access!");
     return StringRef(Tok.Data, Tok.Length);