[PowerPC] Clean up generation of ha16() / lo16() markers

When targeting the Darwin assembler, we need to generate markers ha16() and
lo16() to designate the high and low parts of a (symbolic) immediate.  This
is necessary not just for plain symbols, but also for certain symbolic
expression, typically along the lines of ha16(A - B).  The latter doesn't
work when simply using VariantKind flags on the symbol reference.
This is why the current back-end uses hacks (explicitly called out as such
via multiple FIXMEs) in the symbolLo/symbolHi print methods.

This patch uses target-defined MCExpr codes to represent the Darwin
ha16/lo16 constructs, following along the lines of the equivalent solution
used by the ARM back end to handle their :upper16: / :lower16: markers.
This allows us to get rid of special handling both in the symbolLo/symbolHi
print method and in the common code MCExpr::print routine.  Instead, the
ha16 / lo16 markers are printed simply in a custom print routine for the
target MCExpr types.  (As a result, the symbolLo/symbolHi print methods
can now replaced by a single printS16ImmOperand routine that also handles
symbolic operands.)

The patch also provides a EvaluateAsRelocatableImpl routine to handle
ha16/lo16 constructs.  This is not actually used at the moment by any
in-tree code, but is provided as it makes merging into David Fang's
out-of-tree Mach-O object writer simpler.

Since there is no longer any need to treat VK_PPC_GAS_HA16 and
VK_PPC_DARWIN_HA16 differently, they are merged into a single
VK_PPC_ADDR16_HA (and likewise for the _LO16 types).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182616 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 5 insertions, 41 deletions

diff --git a/lib/Target/PowerPC/InstPrinter/PPCInstPrinter.cpp b/lib/Target/PowerPC/InstPrinter/PPCInstPrinter.cpp
index 3dc7170..432167e 100644
--- a/lib/Target/PowerPC/InstPrinter/PPCInstPrinter.cpp
+++ b/lib/Target/PowerPC/InstPrinter/PPCInstPrinter.cpp
@@ -129,7 +129,10 @@ void PPCInstPrinter::printU6ImmOperand(const MCInst *MI, unsigned OpNo,
 
 void PPCInstPrinter::printS16ImmOperand(const MCInst *MI, unsigned OpNo,
                                         raw_ostream &O) {
-  O << (short)MI->getOperand(OpNo).getImm();
+  if (MI->getOperand(OpNo).isImm())
+    O << (short)MI->getOperand(OpNo).getImm();
+  else
+    printOperand(MI, OpNo, O);
 }
 
 void PPCInstPrinter::printU16ImmOperand(const MCInst *MI, unsigned OpNo,
@@ -174,7 +177,7 @@ void PPCInstPrinter::printcrbitm(const MCInst *MI, unsigned OpNo,
 
 void PPCInstPrinter::printMemRegImm(const MCInst *MI, unsigned OpNo,
                                     raw_ostream &O) {
-  printSymbolLo(MI, OpNo, O);
+  printS16ImmOperand(MI, OpNo, O);
   O << '(';
   if (MI->getOperand(OpNo+1).getReg() == PPC::R0)
     O << "0";
@@ -232,39 +235,4 @@ void PPCInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
   assert(Op.isExpr() && "unknown operand kind in printOperand");
   O << *Op.getExpr();
 }
-  
-void PPCInstPrinter::printSymbolLo(const MCInst *MI, unsigned OpNo,
-                                   raw_ostream &O) {
-  if (MI->getOperand(OpNo).isImm())
-    return printS16ImmOperand(MI, OpNo, O);
-  
-  // FIXME: This is a terrible hack because we can't encode lo16() as an operand
-  // flag of a subtraction.  See the FIXME in GetSymbolRef in PPCMCInstLower.
-  if (MI->getOperand(OpNo).isExpr() &&
-      isa<MCBinaryExpr>(MI->getOperand(OpNo).getExpr())) {
-    O << "lo16(";
-    printOperand(MI, OpNo, O);
-    O << ')';
-  } else {
-    printOperand(MI, OpNo, O);
-  }
-}
-
-void PPCInstPrinter::printSymbolHi(const MCInst *MI, unsigned OpNo,
-                                   raw_ostream &O) {
-  if (MI->getOperand(OpNo).isImm())
-    return printS16ImmOperand(MI, OpNo, O);
-
-  // FIXME: This is a terrible hack because we can't encode lo16() as an operand
-  // flag of a subtraction.  See the FIXME in GetSymbolRef in PPCMCInstLower.
-  if (MI->getOperand(OpNo).isExpr() &&
-      isa<MCBinaryExpr>(MI->getOperand(OpNo).getExpr())) {
-    O << "ha16(";
-    printOperand(MI, OpNo, O);
-    O << ')';
-  } else {
-    printOperand(MI, OpNo, O);
-  }
-}
-
 
diff --git a/lib/Target/PowerPC/InstPrinter/PPCInstPrinter.h b/lib/Target/PowerPC/InstPrinter/PPCInstPrinter.h
index 76f90ef..f64a329 100644
--- a/lib/Target/PowerPC/InstPrinter/PPCInstPrinter.h
+++ b/lib/Target/PowerPC/InstPrinter/PPCInstPrinter.h
@@ -57,10 +57,6 @@ public:
 
   void printMemRegImm(const MCInst *MI, unsigned OpNo, raw_ostream &O);
   void printMemRegReg(const MCInst *MI, unsigned OpNo, raw_ostream &O);
-  
-  // FIXME: Remove
-  void printSymbolLo(const MCInst *MI, unsigned OpNo, raw_ostream &O);
-  void printSymbolHi(const MCInst *MI, unsigned OpNo, raw_ostream &O);
 };
 } // end namespace llvm