From e409f0a779008ad71f8ebb88431630d1d9e33a86 Mon Sep 17 00:00:00 2001
From: Sanjiv Gupta <sanjiv.gupta@microchip.com>
Date: Thu, 30 Jul 2009 04:15:15 +0000
Subject: [PATCH] Keep track of references to mem(cpy,move,set) and then print
 only one extern declaration for them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77578 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/PIC16/PIC16.h             | 14 ++++++++++++++
 lib/Target/PIC16/PIC16AsmPrinter.cpp | 29 ++++++++++++++++++++++++++--
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/lib/Target/PIC16/PIC16.h b/lib/Target/PIC16/PIC16.h
index 447beba7d69..09453fb3c61 100644
--- a/lib/Target/PIC16/PIC16.h
+++ b/lib/Target/PIC16/PIC16.h
@@ -255,6 +255,20 @@ namespace PIC16CC {
       return false;
     }
 
+    // FIXME: currently we track both @memcpy and memcpy, as 
+    // the first one is generated by clang, and the second one by codegen
+    // while lowering intrinsics. One we fix codegen to use RTLIB, we can
+    // have only @memcpy here.
+    inline static bool isMemIntrinsic (const std::string &Name) {
+      if (Name.compare("@memcpy") == 0 || Name.compare("memcpy") == 0 ||
+          Name.compare("@memset") == 0 || Name.compare("memset") == 0 ||
+          Name.compare("@memmove") == 0 || Name.compare("memmove") == 0) {
+        return true;
+      }
+      
+      return false;
+    }
+
     inline static bool isLocalToFunc (std::string &Func, std::string &Var) {
       if (! isLocalName(Var)) return false;
 
diff --git a/lib/Target/PIC16/PIC16AsmPrinter.cpp b/lib/Target/PIC16/PIC16AsmPrinter.cpp
index 4a35a1e2879..743ce9f09fe 100644
--- a/lib/Target/PIC16/PIC16AsmPrinter.cpp
+++ b/lib/Target/PIC16/PIC16AsmPrinter.cpp
@@ -137,7 +137,15 @@ void PIC16AsmPrinter::printOperand(const MachineInstr *MI, int opNum) {
       return;
 
     case MachineOperand::MO_GlobalAddress: {
-      O << Mang->getMangledName(MO.getGlobal());
+      std::string Sname = Mang->getMangledName(MO.getGlobal());
+      // FIXME: currently we do not have a memcpy def coming in the module
+      // by any chance, as we do not link in those as .bc lib. So these calls
+      // are always external and it is safe to emit an extern.
+      if (PAN::isMemIntrinsic(Sname)) {
+        LibcallDecls.push_back(createESName(Sname));
+      }
+
+      O << Sname;
       break;
     }
     case MachineOperand::MO_ExternalSymbol: {
@@ -148,7 +156,14 @@ void PIC16AsmPrinter::printOperand(const MachineInstr *MI, int opNum) {
         LibcallDecls.push_back(Sname);
       }
 
-      O  << Sname;
+      // Record a call to intrinsic to print the extern declaration for it.
+      std::string Sym = Sname;  
+      if (PAN::isMemIntrinsic(Sym)) {
+        Sym = PAN::addPrefix(Sym);
+        LibcallDecls.push_back(createESName(Sym));
+      }
+
+      O  << Sym;
       break;
     }
     case MachineOperand::MO_MachineBasicBlock:
@@ -253,6 +268,16 @@ void PIC16AsmPrinter::EmitFunctionDecls(Module &M) {
     if (!I->isDeclaration() && !I->hasExternalLinkage())
       continue;
 
+    // Do not emit memcpy, memset, and memmove here.
+    // Calls to these routines can be generated in two ways,
+    // 1. User calling the standard lib function
+    // 2. Codegen generating these calls for llvm intrinsics.
+    // In the first case a prototype is alread availale, while in
+    // second case the call is via and externalsym and the prototype is missing.
+    // So declarations for these are currently always getting printing by
+    // tracking both kind of references in printInstrunction.
+    if (I->isDeclaration() && PAN::isMemIntrinsic(Name)) continue;
+
     const char *directive = I->isDeclaration() ? TAI->getExternDirective() :
                                                  TAI->getGlobalDirective();