The inline asm operand modifier 'c' is suppose

to be generic across architectures. It has the
following description in the gnu sources:

    Substitute immediate value without immediate syntax

Several Architectures such as x86 have local implementations
of operand modifier 'c' which go beyond the above description
slightly. To make use of the generic modifiers without overriding
local implementation one can make a call to the base class method
for AsmPrinter::PrintAsmOperand() in the locally derived method's 
"default" case in the switch statement. That way if it is already
defined locally the generic version will never get called.

This change is needed when test/CodeGen/generic/asm-large-immediate.ll
failed on a native Mips board. The test was assuming a generic
implementation was in place.

Affected files:

    lib/Target/Mips/MipsAsmPrinter.cpp:
        Changed the default case to call the base method.
    lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
        Added 'c' to the switch cases.
    test/CodeGen/Mips/asm-large-immediate.ll
        Mips compiled version of the generic one

Contributer: Jack Carter
llvm-svn: 158925

1 files changed, 17 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
index 1844e44a47a..58716b725bf 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
@@ -409,9 +409,23 @@ void AsmPrinter::PrintSpecial(const MachineInstr *MI, raw_ostream &OS,
 /// instruction, using the specified assembler variant.  Targets should
 /// override this to format as appropriate.
 bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
-                                 unsigned AsmVariant, const char *ExtraCode,
-                                 raw_ostream &O) {
-  // Target doesn't support this yet!
+    unsigned AsmVariant, const char *ExtraCode,
+    raw_ostream &O) {
+  // Does this asm operand have a single letter operand modifier?
+  if (ExtraCode && ExtraCode[0]) {
+    if (ExtraCode[1] != 0) return true; // Unknown modifier.
+
+    const MachineOperand &MO = MI->getOperand(OpNo);
+    switch (ExtraCode[0]) {
+    default:
+      return true;  // Unknown modifier.
+    case 'c': // Substitute immediate value without immediate syntax
+      if ((MO.getType()) != MachineOperand::MO_Immediate)
+        return true;
+      O << MO.getImm();
+      return false;
+    }
+  }
   return true;
 }