Treat [1 x i8] zeroinitializer as a C string, placing such stuff into

mergeable string section. I don't see any bad impact of such decision
(rather then placing it into mergeable const section, as it was before),
but at least Darwin linker won't complain anymore.

The problem in LLVM is that we don't have special type for string constants
(like gcc does). Even more, we have two separate types: ConstatArray for non-null
strings and ConstantAggregateZero for null stuff.... It's a bit weird :)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63142 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/DarwinTargetAsmInfo.cpp b/lib/Target/DarwinTargetAsmInfo.cpp
index 57e70148f481fbb8728a3752bfefa7db9d75d5fa..cc05c09c5170a1b401706e4317e49f11410b98de 100644 (file)
--- a/lib/Target/DarwinTargetAsmInfo.cpp
+++ b/lib/Target/DarwinTargetAsmInfo.cpp
@@ -115,9 +115,9 @@ const Section*
 DarwinTargetAsmInfo::MergeableStringSection(const GlobalVariable *GV) const {
   const TargetData *TD = TM.getTargetData();
   Constant *C = cast<GlobalVariable>(GV)->getInitializer();
-  const Type *Type = cast<ConstantArray>(C)->getType()->getElementType();
+  const Type *Ty = cast<ArrayType>(C->getType())->getElementType();
 
-  unsigned Size = TD->getTypePaddedSize(Type);
+  unsigned Size = TD->getTypePaddedSize(Ty);
   if (Size) {
     unsigned Align = TD->getPreferredAlignment(GV);
     if (Align <= 32)

diff --git a/lib/Target/ELFTargetAsmInfo.cpp b/lib/Target/ELFTargetAsmInfo.cpp
index 5a3b93a52f37b0ac78dfd9a92a9f31623bbed979..624b95c7b6c162e643545d7665d0c968a507c83a 100644 (file)
--- a/lib/Target/ELFTargetAsmInfo.cpp
+++ b/lib/Target/ELFTargetAsmInfo.cpp
@@ -126,8 +126,7 @@ const Section*
 ELFTargetAsmInfo::MergeableStringSection(const GlobalVariable *GV) const {
   const TargetData *TD = TM.getTargetData();
   Constant *C = cast<GlobalVariable>(GV)->getInitializer();
-  const ConstantArray *CVA = cast<ConstantArray>(C);
-  const Type *Ty = CVA->getType()->getElementType();
+  const Type *Ty = cast<ArrayType>(C->getType())->getElementType();
 
   unsigned Size = TD->getTypePaddedSize(Ty);
   if (Size <= 16) {

diff --git a/lib/Target/TargetAsmInfo.cpp b/lib/Target/TargetAsmInfo.cpp
index 4666875c34c2fdfdc0b06e8280fa8ffde4cc51c5..d687e2f44cfd7787a2b541d66fe0ade02550f762 100644 (file)
--- a/lib/Target/TargetAsmInfo.cpp
+++ b/lib/Target/TargetAsmInfo.cpp
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
 #include "llvm/GlobalVariable.h"
 #include "llvm/Function.h"
 #include "llvm/Module.h"
@@ -170,6 +171,25 @@ static bool isSuitableForBSS(const GlobalVariable *GV) {
   return (C->isNullValue() && !GV->isConstant() && !NoZerosInBSS);
 }
 
+static bool isConstantString(const Constant *C) {
+  // First check: is we have constant array of i8 terminated with zero
+  const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
+  // Check, if initializer is a null-terminated string
+  if (CVA && CVA->isCString())
+    return true;
+
+  // Another possibility: [1 x i8] zeroinitializer
+  if (isa<ConstantAggregateZero>(C)) {
+    if (const ArrayType *Ty = dyn_cast<ArrayType>(C->getType())) {
+      return (Ty->getElementType() == Type::Int8Ty &&
+              Ty->getNumElements() == 1);
+    }
+  }
+
+  return false;
+}
+
+
 SectionKind::Kind
 TargetAsmInfo::SectionKindForGlobal(const GlobalValue *GV) const {
   // Early exit - functions should be always in text sections.
@@ -191,9 +211,8 @@ TargetAsmInfo::SectionKindForGlobal(const GlobalValue *GV) const {
     if (C->ContainsRelocations())
       return SectionKind::ROData;
     else {
-      const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
       // Check, if initializer is a null-terminated string
-      if (CVA && CVA->isCString())
+      if (isConstantString(C))
         return SectionKind::RODataMergeStr;
       else
         return SectionKind::RODataMergeConst;