Adding back support for printing operands symbolically to ARM's new disassembler

using llvm's public 'C' disassembler API now including annotations.

Hooked this up to Darwin's otool(1) so it can again print things like branch
targets for example this:
 blx _puts
instead of this:
 blx #-36
and includes support for annotations for branches to symbol stubs like:
 bl	0x40 @ symbol stub for: _puts
and annotations for pc relative loads like this:
 ldr	r3, #8 @ literal pool for: Hello, world!
Also again can print the expression encoded in the Mach-O relocation entries for
things like this:
 movt r0, :upper16:((_foo-_bar)+1234)

llvm-svn: 141129

1 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp b/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
index f3e29f80b8f..e70f8460d6f 100644
--- a/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
+++ b/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
@@ -207,7 +207,18 @@ void ARMInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
     O << '#' << Op.getImm();
   } else {
     assert(Op.isExpr() && "unknown operand kind in printOperand");
-    O << *Op.getExpr();
+    // If a symbolic branch target was added as a constant expression then print
+    // that address in hex.
+    const MCConstantExpr *BranchTarget = dyn_cast<MCConstantExpr>(Op.getExpr());
+    int64_t Address;
+    if (BranchTarget && BranchTarget->EvaluateAsAbsolute(Address)) {
+      O << "0x";
+      O.write_hex(Address);
+    }
+    else {
+      // Otherwise, just print the expression.
+      O << *Op.getExpr();
+    }
   }
 }