[llvm] 61b5e72 - [AIX] Use csect reference for function address constants

[via llvm-commits]

Author: diggerlin
Date: 2020-01-06T11:38:22-05:00
New Revision: 61b5e727b7ccfca7e0cbb0ed70f9e828cd1514bd

URL: https://github.com/llvm/llvm-project/commit/61b5e727b7ccfca7e0cbb0ed70f9e828cd1514bd
DIFF: https://github.com/llvm/llvm-project/commit/61b5e727b7ccfca7e0cbb0ed70f9e828cd1514bd.diff

LOG: [AIX] Use csect reference for function address constants

SUMMARY:
We currently emit a reference for function address constants as labels;
for example:

foo_ptr:
.long foo
however, there may be no such label in the case where the function is
undefined. Although the label exists when the function is defined, we
will (to be consistent) also use a csect reference in that case.

Reviewers: daltenty,hubert.reinterpretcast,jasonliu,Xiangling_L
Subscribers: cebowleratibm, wuzish, nemanjai

Differential Revision: https://reviews.llvm.org/D71144

Added: 
    llvm/test/CodeGen/PowerPC/aix-reference-func-addr-const.ll

Modified: 
    llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 1a45ad1fa9b4..31fd7b2b5624 100644
--- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -177,6 +177,8 @@ class PPCAIXAsmPrinter : public PPCAsmPrinter {
 
   void SetupMachineFunction(MachineFunction &MF) override;
 
+  const MCExpr *lowerConstant(const Constant *CV) override;
+
   void EmitGlobalVariable(const GlobalVariable *GV) override;
 
   void EmitFunctionDescriptor() override;
@@ -1763,6 +1765,26 @@ void PPCAIXAsmPrinter::ValidateGV(const GlobalVariable *GV) {
     report_fatal_error("COMDAT not yet supported by AIX.");
 }
 
+const MCExpr *PPCAIXAsmPrinter::lowerConstant(const Constant *CV) {
+  if (const Function *F = dyn_cast<Function>(CV)) {
+    MCSymbolXCOFF *FSym = cast<MCSymbolXCOFF>(getSymbol(F));
+    if (!FSym->hasContainingCsect()) {
+      const XCOFF::StorageClass SC =
+          F->isDeclaration()
+              ? TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(F)
+              : XCOFF::C_HIDEXT;
+      MCSectionXCOFF *Csect = OutStreamer->getContext().getXCOFFSection(
+          FSym->getName(), XCOFF::XMC_DS,
+          F->isDeclaration() ? XCOFF::XTY_ER : XCOFF::XTY_SD, SC,
+          SectionKind::getMetadata());
+      FSym->setContainingCsect(Csect);
+    }
+    return MCSymbolRefExpr::create(
+        FSym->getContainingCsect()->getQualNameSymbol(), OutContext);
+  }
+  return PPCAsmPrinter::lowerConstant(CV);
+}
+
 void PPCAIXAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
   ValidateGV(GV);
 

diff  --git a/llvm/test/CodeGen/PowerPC/aix-reference-func-addr-const.ll b/llvm/test/CodeGen/PowerPC/aix-reference-func-addr-const.ll
new file mode 100644
index 000000000000..88d5f3d1427d
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/aix-reference-func-addr-const.ll
@@ -0,0 +1,32 @@
+; RUN: llc -verify-machineinstrs -mcpu=pwr4 -mtriple powerpc-ibm-aix-xcoff < %s | FileCheck %s
+; RUN: llc -verify-machineinstrs -mcpu=pwr4 -mtriple powerpc64-ibm-aix-xcoff < %s | FileCheck --check-prefix=CHECK64 %s
+
+ at foo_ptr = global void (...)* @foo
+declare void @foo(...)
+
+ at bar_ptr1 = global void (...)* bitcast (void ()* @bar to void (...)*)
+define void @bar() {
+entry:
+  ret void
+}
+
+
+;CHECK:          .csect .data[RW]
+;CHECK-NEXT:     .globl  foo_ptr
+;CHECK-NEXT:     .align  2
+;CHECK-NEXT:     foo_ptr:
+;CHECK-NEXT:     .long   foo[DS]
+;CHECK-NEXT:     .globl  bar_ptr1
+;CHECK-NEXT:     .align  2
+;CHECK-NEXT:     bar_ptr1:
+;CHECK-NEXT:     .long   bar[DS]
+
+;CHECK64:         .csect .data[RW]
+;CHECK64-NEXT:         .globl  foo_ptr
+;CHECK64-NEXT:         .align  3
+;CHECK64-NEXT:    foo_ptr:
+;CHECK64-NEXT:         .llong  foo[DS]
+;CHECK64-NEXT:         .globl  bar_ptr1
+;CHECK64-NEXT:         .align  3
+;CHECK64-NEXT:    bar_ptr1:
+;CHECK64-NEXT:         .llong  bar[DS]