[PATCH] D21490: Print call preserved registers in comments at call site in assembly files.

[Vivek Pandya via llvm-commits]

vivekvpandya created this revision.
vivekvpandya added reviewers: qcolombet, mehdi_amini.
vivekvpandya added subscribers: MatzeB, hfinkel, mcrosier, llvm-commits.

This patch makes AsmPrinter print call preserved registers in comments at call site in assembly files. 

http://reviews.llvm.org/D21490

Files:
  lib/CodeGen/AsmPrinter/AsmPrinter.cpp

Index: lib/CodeGen/AsmPrinter/AsmPrinter.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -27,6 +27,7 @@
 #include "llvm/CodeGen/MachineJumpTableInfo.h"
 #include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
+#include "llvm/CodeGen/MachineOperand.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/Mangler.h"
@@ -623,6 +624,7 @@
 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
   const MachineFunction *MF = MI.getParent()->getParent();
   const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
+  const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
 
   // Check for spills and reloads
   int FI;
@@ -653,6 +655,22 @@
   // Check for spill-induced copies
   if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
     CommentOS << " Reload Reuse\n";
+
+  if (MI.isCall()) {
+    const uint32_t *CalleeRegMask;
+    CommentOS << "Call Preserved Registers: ";
+
+    for (const MachineOperand &MO : MI.operands())
+      if (MO.isRegMask()) {
+        CalleeRegMask = MO.getRegMask();
+        break;
+      }
+
+    for (unsigned PReg = 1, PRegE = TRI->getNumRegs(); PReg < PRegE; ++PReg)
+      if (!MachineOperand::clobbersPhysReg(CalleeRegMask, PReg))
+        CommentOS << TRI->getName(PReg) << " ";
+    CommentOS << "\n";
+  }
 }
 
 /// emitImplicitDef - This method emits the specified machine instruction


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D21490.61167.patch
Type: text/x-patch
Size: 1550 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20160618/53a0246d/attachment.bin>