[PATCH] D119557: [Systemz/z/OS] Centralize emitting the call type information

[Kai Nacke via Phabricator via llvm-commits]

Kai created this revision.
Kai added reviewers: uweigand, jnspaulsson, yusra.syeda, neumannh.
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With XPLINK, a no-op with information about the call type is emitted
after each call instruction. Centralizing it has the advantage that it is
easy to document all cases, and it makes it easier to extend it later
(e.g. dynamic stack allocation, 32 bit mode).
Also add a test checking the call types emitted so far.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D119557

Files:
  llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp
  llvm/lib/Target/SystemZ/SystemZAsmPrinter.h
  llvm/test/CodeGen/SystemZ/call-zos-02.ll


Index: llvm/test/CodeGen/SystemZ/call-zos-02.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/SystemZ/call-zos-02.ll
@@ -0,0 +1,17 @@
+; RUN: llc --mtriple=s390x-ibm-zos --show-mc-encoding < %s | FileCheck %s
+
+define internal signext i32 @caller() {
+entry:
+  ret i32 0
+}
+
+
+define hidden signext i32 @caller2() {
+entry:
+; CHECK-LABEL:   caller2:
+; CHECK:         brasl 7, caller at PLT   * encoding: [0xc0,0x75,A,A,A,A]
+; CHECK-NEXT:    * fixup A - offset: 2, value: caller at PLT+2, kind: FK_390_PC32DBL
+; CHECK-NEXT:    bcr     0, 3          * encoding: [0x07,0x03]
+  %call = call signext i32 @caller()
+  ret i32 %call
+}
Index: llvm/lib/Target/SystemZ/SystemZAsmPrinter.h
===================================================================
--- llvm/lib/Target/SystemZ/SystemZAsmPrinter.h
+++ llvm/lib/Target/SystemZ/SystemZAsmPrinter.h
@@ -33,6 +33,18 @@
     return static_cast<SystemZTargetStreamer *>(TS);
   }
 
+  /// Call type information for XPLINK.
+  enum class CallType {
+    BASR76 = 0,   // b'x000' == BASR  r7,r6
+    BRAS7 = 1,    // b'x001' == BRAS  r7,ep
+    RESVD_2 = 2,  // b'x010'
+    BRASL7 = 3,   // b'x011' == BRASL r7,ep
+    RESVD_4 = 4,  // b'x100'
+    RESVD_5 = 5,  // b'x101'
+    BALR1415 = 6, // b'x110' == BALR  r14,r15
+    BASR33 = 7,   // b'x111' == BASR  r3,r3
+  };
+
 public:
   SystemZAsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
       : AsmPrinter(TM, std::move(Streamer)), SM(*this) {}
@@ -54,6 +66,7 @@
   void emitFunctionEntryLabel() override;
 
 private:
+  void emitCallInformation(CallType CT);
   void LowerFENTRY_CALL(const MachineInstr &MI, SystemZMCInstLower &MCIL);
   void LowerSTACKMAP(const MachineInstr &MI);
   void LowerPATCHPOINT(const MachineInstr &MI, SystemZMCInstLower &Lower);
Index: llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp
===================================================================
--- llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp
+++ llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp
@@ -124,6 +124,13 @@
     .addImm(0);
 }
 
+void SystemZAsmPrinter::emitCallInformation(CallType CT) {
+  EmitToStreamer(*OutStreamer,
+                 MCInstBuilder(SystemZ::BCRAsm)
+                     .addImm(0)
+                     .addReg(SystemZMC::GR64Regs[static_cast<unsigned>(CT)]));
+}
+
 void SystemZAsmPrinter::emitInstruction(const MachineInstr *MI) {
   SystemZMCInstLower Lower(MF->getContext(), *this);
   MCInst LoweredMI;
@@ -234,18 +241,14 @@
                        .addReg(SystemZ::R7D)
                        .addExpr(Lower.getExpr(MI->getOperand(0),
                                               MCSymbolRefExpr::VK_PLT)));
-    EmitToStreamer(
-        *OutStreamer,
-        MCInstBuilder(SystemZ::BCRAsm).addImm(0).addReg(SystemZ::R3D));
+    emitCallInformation(CallType::BRASL7);
     return;
 
   case SystemZ::CallBASR_XPLINK64:
     EmitToStreamer(*OutStreamer, MCInstBuilder(SystemZ::BASR)
                                      .addReg(SystemZ::R7D)
                                      .addReg(MI->getOperand(0).getReg()));
-    EmitToStreamer(
-        *OutStreamer,
-        MCInstBuilder(SystemZ::BCRAsm).addImm(0).addReg(SystemZ::R0D));
+    emitCallInformation(CallType::BASR76);
     return;
 
   case SystemZ::CallBRASL:


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