From 827e3534180a8fa2e745661852849442f01c862d Mon Sep 17 00:00:00 2001
From: Xiangling Liao <Xiangling.Liao@ibm.com>
Date: Wed, 26 Feb 2020 16:48:23 -0500
Subject: [PATCH] [AIX] Handle LinkOnceODRLinkage and AppendingLinkage for
 static init gloabl arrays

Handle LinkOnceODRLinkage;
Handle AppendingLinkage type for llvm.global_ctors/dtors static init global arrays;

Differential Revision: https://reviews.llvm.org/D75305
---
 lib/CodeGen/TargetLoweringObjectFileImpl.cpp  |  4 ++++
 lib/Target/PowerPC/PPCAsmPrinter.cpp          | 13 ++++++++++++
 test/CodeGen/PowerPC/aix-AppendingLinkage.ll  | 21 +++++++++++++++++++
 .../CodeGen/PowerPC/aix-LinkOnceODRLinkage.ll | 13 ++++++++++++
 4 files changed, 51 insertions(+)
 create mode 100644 test/CodeGen/PowerPC/aix-AppendingLinkage.ll
 create mode 100644 test/CodeGen/PowerPC/aix-LinkOnceODRLinkage.ll

diff --git a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index ad0914862b4..d36d04e42cb 100644
--- a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -1948,7 +1948,11 @@ XCOFF::StorageClass TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(
   case GlobalValue::CommonLinkage:
     return XCOFF::C_EXT;
   case GlobalValue::ExternalWeakLinkage:
+  case GlobalValue::LinkOnceODRLinkage:
     return XCOFF::C_WEAKEXT;
+  case GlobalValue::AppendingLinkage:
+    report_fatal_error(
+        "There is no mapping that implements AppendingLinkage for XCOFF.");
   default:
     report_fatal_error(
         "Unhandled linkage when mapping linkage to StorageClass.");
diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 904751801d5..c1d88f57e24 100644
--- a/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -1579,9 +1579,22 @@ const MCExpr *PPCAIXAsmPrinter::lowerConstant(const Constant *CV) {
   return PPCAsmPrinter::lowerConstant(CV);
 }
 
+static bool isSpecialLLVMGlobalArrayForStaticInit(const GlobalVariable *GV) {
+  return StringSwitch<bool>(GV->getName())
+      .Cases("llvm.global_ctors", "llvm.global_dtors", true)
+      .Default(false);
+}
+
 void PPCAIXAsmPrinter::emitGlobalVariable(const GlobalVariable *GV) {
   ValidateGV(GV);
 
+  // TODO: Update the handling of global arrays for static init when we support
+  // the ".ref" directive.
+  // Otherwise, we can skip these arrays, because the AIX linker collects
+  // static init functions simply based on their name.
+  if (isSpecialLLVMGlobalArrayForStaticInit(GV))
+    return;
+
   // Create the symbol, set its storage class.
   MCSymbolXCOFF *GVSym = cast<MCSymbolXCOFF>(getSymbol(GV));
   GVSym->setStorageClass(
diff --git a/test/CodeGen/PowerPC/aix-AppendingLinkage.ll b/test/CodeGen/PowerPC/aix-AppendingLinkage.ll
new file mode 100644
index 00000000000..2809aab5a71
--- /dev/null
+++ b/test/CodeGen/PowerPC/aix-AppendingLinkage.ll
@@ -0,0 +1,21 @@
+; RUN: llc -verify-machineinstrs -mcpu=pwr4 -mtriple powerpc-ibm-aix-xcoff < \
+; RUN: %s | FileCheck %s
+
+; RUN: llc -verify-machineinstrs -mcpu=pwr4 -mtriple powerpc64-ibm-aix-xcoff < \
+; RUN: %s | FileCheck %s
+
+@llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @foo, i8* null }]
+@llvm.global_dtors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @bar, i8* null }]
+
+define dso_local void @foo() {
+entry:
+  ret void
+}
+
+define dso_local void @bar() {
+entry:
+  ret void
+}
+
+; CHECK-NOT: llvm.global_ctors
+; CHECK-NOT: llvm.global_dtors
diff --git a/test/CodeGen/PowerPC/aix-LinkOnceODRLinkage.ll b/test/CodeGen/PowerPC/aix-LinkOnceODRLinkage.ll
new file mode 100644
index 00000000000..7c9c80b9cc4
--- /dev/null
+++ b/test/CodeGen/PowerPC/aix-LinkOnceODRLinkage.ll
@@ -0,0 +1,13 @@
+; RUN: llc -mtriple powerpc-ibm-aix-xcoff < %s | \
+; RUN: FileCheck %s
+
+; RUN: llc -mtriple powerpc64-ibm-aix-xcoff < %s | \
+; RUN: FileCheck %s
+
+define linkonce_odr void @_Z3fooIiEvT_() {
+entry:
+  ret void
+}
+
+; CHECK: .weak   _Z3fooIiEvT_
+; CHECK: .weak   ._Z3fooIiEvT_