From e9ac1495e2082ebacfe14df2ffd124a58860449d Mon Sep 17 00:00:00 2001
From: diggerlin <digger.llvm@gmail.com>
Date: Tue, 11 Aug 2020 15:26:19 -0400
Subject: [AIX][XCOFF] change the operand of branch instruction from symbol
 name to qualified symbol name for function declarations

SUMMARY:

1. in the patch  , remove setting storageclass in function .getXCOFFSection and construct function of class MCSectionXCOFF
there are

XCOFF::StorageMappingClass MappingClass;
XCOFF::SymbolType Type;
XCOFF::StorageClass StorageClass;
in the MCSectionXCOFF class,
these attribute only used in the XCOFFObjectWriter, (asm path do not need the StorageClass)

we need get the value of StorageClass, Type,MappingClass before we invoke the getXCOFFSection every time.

actually , we can get the StorageClass of the MCSectionXCOFF  from it's delegated symbol.

2. we also change the oprand of branch instruction from symbol name to qualify symbol name.
for example change
bl .foo
extern .foo
to
bl .foo[PR]
extern .foo[PR]

3. and if there is reference indirect call a function bar.
we also add
  extern .bar[PR]

Reviewers:  Jason liu, Xiangling Liao

Differential Revision: https://reviews.llvm.org/D84765
---
 llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp | 35 +++++++++--------------
 1 file changed, 13 insertions(+), 22 deletions(-)

(limited to 'llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp')

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 8a0aacc4cee2..4c3e6cce7836 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -2016,13 +2016,11 @@ MCSection *TargetLoweringObjectFileXCOFF::getSectionForExternalReference(
 
   SmallString<128> Name;
   getNameWithPrefix(Name, GO, TM);
-  XCOFF::StorageClass SC =
-      TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(GO);
 
   // Externals go into a csect of type ER.
   return getContext().getXCOFFSection(
       Name, isa<Function>(GO) ? XCOFF::XMC_DS : XCOFF::XMC_UA, XCOFF::XTY_ER,
-      SC, SectionKind::getMetadata());
+      SectionKind::getMetadata());
 }
 
 MCSection *TargetLoweringObjectFileXCOFF::SelectSectionForGlobal(
@@ -2035,11 +2033,9 @@ MCSection *TargetLoweringObjectFileXCOFF::SelectSectionForGlobal(
   if (Kind.isBSSLocal() || Kind.isCommon()) {
     SmallString<128> Name;
     getNameWithPrefix(Name, GO, TM);
-    XCOFF::StorageClass SC =
-        TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(GO);
     return getContext().getXCOFFSection(
         Name, Kind.isBSSLocal() ? XCOFF::XMC_BS : XCOFF::XMC_RW, XCOFF::XTY_CM,
-        SC, Kind, /* BeginSymbolName */ nullptr);
+        Kind, /* BeginSymbolName */ nullptr);
   }
 
   if (Kind.isMergeableCString()) {
@@ -2051,10 +2047,8 @@ MCSection *TargetLoweringObjectFileXCOFF::SelectSectionForGlobal(
     SmallString<128> Name;
     Name = SizeSpec + utostr(Alignment.value());
 
-    return getContext().getXCOFFSection(
-        Name, XCOFF::XMC_RO, XCOFF::XTY_SD,
-        TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(GO),
-        Kind, /* BeginSymbolName */ nullptr);
+    return getContext().getXCOFFSection(Name, XCOFF::XMC_RO, XCOFF::XTY_SD,
+                                        Kind, /*BeginSymbolName*/ nullptr);
   }
 
   if (Kind.isText()) {
@@ -2095,7 +2089,6 @@ MCSection *TargetLoweringObjectFileXCOFF::getSectionForJumpTable(
   SmallString<128> NameStr(".rodata.jmp..");
   getNameWithPrefix(NameStr, &F, TM);
   return getContext().getXCOFFSection(NameStr, XCOFF::XMC_RO, XCOFF::XTY_SD,
-                                      XCOFF::C_HIDEXT,
                                       SectionKind::getReadOnly());
 }
 
@@ -2176,16 +2169,15 @@ MCSymbol *TargetLoweringObjectFileXCOFF::getFunctionEntryPointSymbol(
 
   // When -function-sections is enabled, it's not necessary to emit
   // function entry point label any more. We will use function entry
-  // point csect instead. For function delcarations, it's okay to continue
-  // using label semantic because undefined symbols gets treated as csect with
-  // XTY_ER property anyway.
-  if (TM.getFunctionSections() && !Func->isDeclaration() &&
+  // point csect instead. And for function delcarations, the undefined symbols
+  // gets treated as csect with XTY_ER property.
+  if ((TM.getFunctionSections() || Func->isDeclaration()) &&
       isa<Function>(Func)) {
-    XCOFF::StorageClass SC =
-        TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(Func);
-    return cast<MCSectionXCOFF>(getContext().getXCOFFSection(
-                                    NameStr, XCOFF::XMC_PR, XCOFF::XTY_SD, SC,
-                                    SectionKind::getText()))
+    return cast<MCSectionXCOFF>(
+               getContext().getXCOFFSection(
+                   NameStr, XCOFF::XMC_PR,
+                   Func->isDeclaration() ? XCOFF::XTY_ER : XCOFF::XTY_SD,
+                   SectionKind::getText()))
         ->getQualNameSymbol();
   }
 
@@ -2197,7 +2189,6 @@ MCSection *TargetLoweringObjectFileXCOFF::getSectionForFunctionDescriptor(
   SmallString<128> NameStr;
   getNameWithPrefix(NameStr, F, TM);
   return getContext().getXCOFFSection(NameStr, XCOFF::XMC_DS, XCOFF::XTY_SD,
-                                      getStorageClassForGlobal(F),
                                       SectionKind::getData());
 }
 
@@ -2208,5 +2199,5 @@ MCSection *TargetLoweringObjectFileXCOFF::getSectionForTOCEntry(
   return getContext().getXCOFFSection(
       cast<MCSymbolXCOFF>(Sym)->getSymbolTableName(),
       TM.getCodeModel() == CodeModel::Large ? XCOFF::XMC_TE : XCOFF::XMC_TC,
-      XCOFF::XTY_SD, XCOFF::C_HIDEXT, SectionKind::getData());
+      XCOFF::XTY_SD, SectionKind::getData());
 }
-- 
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