Reduce heap trashing due to std::string construction / concatenation via caching of section flags string representations
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54842 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Target/ELFTargetAsmInfo.h b/include/llvm/Target/ELFTargetAsmInfo.h
index fe339f8..3dacb33 100644
--- a/include/llvm/Target/ELFTargetAsmInfo.h
+++ b/include/llvm/Target/ELFTargetAsmInfo.h
@@ -27,7 +27,7 @@
explicit ELFTargetAsmInfo(const TargetMachine &TM);
virtual const Section* SelectSectionForGlobal(const GlobalValue *GV) const;
- virtual std::string PrintSectionFlags(unsigned flags) const;
+ virtual std::string printSectionFlags(unsigned flags) const;
const Section* MergeableConstSection(const GlobalVariable *GV) const;
inline const Section* MergeableConstSection(const Type *Ty) const;
const Section* MergeableStringSection(const GlobalVariable *GV) const;
diff --git a/include/llvm/Target/TargetAsmInfo.h b/include/llvm/Target/TargetAsmInfo.h
index 04e91cb..8eb9515 100644
--- a/include/llvm/Target/TargetAsmInfo.h
+++ b/include/llvm/Target/TargetAsmInfo.h
@@ -16,6 +16,7 @@
#ifndef LLVM_TARGET_ASM_INFO_H
#define LLVM_TARGET_ASM_INFO_H
+#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/DataTypes.h"
#include <string>
@@ -83,6 +84,16 @@
static inline unsigned setEntitySize(unsigned Flags, unsigned Size) {
return ((Flags & ~EntitySize) | ((Size & 0xFF) << 24));
}
+
+ struct KeyInfo {
+ static inline unsigned getEmptyKey() { return Invalid; }
+ static inline unsigned getTombstoneKey() { return Invalid - 1; }
+ static unsigned getHashValue(const unsigned &Key) { return Key; }
+ static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
+ static bool isPod() { return true; }
+ };
+
+ typedef DenseMap<unsigned, std::string, KeyInfo> FlagsStringsMapType;
}
class TargetMachine;
@@ -109,6 +120,7 @@
class TargetAsmInfo {
private:
mutable StringMap<Section> Sections;
+ mutable SectionFlags::FlagsStringsMapType FlagsStrings;
protected:
//===------------------------------------------------------------------===//
// Properties to be set by the target writer, used to configure asm printer.
@@ -551,7 +563,8 @@
virtual std::string UniqueSectionForGlobal(const GlobalValue* GV,
SectionKind::Kind kind) const;
- virtual std::string PrintSectionFlags(unsigned flags) const { return ""; }
+ const std::string& getSectionFlags(unsigned Flags) const;
+ virtual std::string printSectionFlags(unsigned flags) const { return ""; }
virtual const Section* SelectSectionForGlobal(const GlobalValue *GV) const;
diff --git a/lib/Target/ELFTargetAsmInfo.cpp b/lib/Target/ELFTargetAsmInfo.cpp
index 82ac847..9ffc72d 100644
--- a/lib/Target/ELFTargetAsmInfo.cpp
+++ b/lib/Target/ELFTargetAsmInfo.cpp
@@ -148,7 +148,7 @@
return getReadOnlySection_();
}
-std::string ELFTargetAsmInfo::PrintSectionFlags(unsigned flags) const {
+std::string ELFTargetAsmInfo::printSectionFlags(unsigned flags) const {
std::string Flags = ",\"";
if (!(flags & SectionFlags::Debug))
diff --git a/lib/Target/Sparc/SparcTargetAsmInfo.cpp b/lib/Target/Sparc/SparcTargetAsmInfo.cpp
index c81b9e1..afa5327 100644
--- a/lib/Target/Sparc/SparcTargetAsmInfo.cpp
+++ b/lib/Target/Sparc/SparcTargetAsmInfo.cpp
@@ -27,9 +27,9 @@
CStringSection=".rodata.str";
}
-std::string SparcELFTargetAsmInfo::PrintSectionFlags(unsigned flags) const {
+std::string SparcELFTargetAsmInfo::printSectionFlags(unsigned flags) const {
if (flags & SectionFlags::Mergeable)
- return ELFTargetAsmInfo::PrintSectionFlags(flags);
+ return ELFTargetAsmInfo::printSectionFlags(flags);
std::string Flags;
if (!(flags & SectionFlags::Debug))
diff --git a/lib/Target/Sparc/SparcTargetAsmInfo.h b/lib/Target/Sparc/SparcTargetAsmInfo.h
index 253a5d7..1af5d80 100644
--- a/lib/Target/Sparc/SparcTargetAsmInfo.h
+++ b/lib/Target/Sparc/SparcTargetAsmInfo.h
@@ -25,7 +25,7 @@
struct SparcELFTargetAsmInfo : public ELFTargetAsmInfo {
explicit SparcELFTargetAsmInfo(const TargetMachine &TM);
- std::string PrintSectionFlags(unsigned flags) const;
+ std::string printSectionFlags(unsigned flags) const;
};
} // namespace llvm
diff --git a/lib/Target/TargetAsmInfo.cpp b/lib/Target/TargetAsmInfo.cpp
index 9bc0b40..1ef2182 100644
--- a/lib/Target/TargetAsmInfo.cpp
+++ b/lib/Target/TargetAsmInfo.cpp
@@ -291,7 +291,7 @@
// If section is named we need to switch into it via special '.section'
// directive and also append funky flags. Otherwise - section name is just
// some magic assembler directive.
- return getSwitchToSectionDirective() + S->Name + PrintSectionFlags(S->Flags);
+ return getSwitchToSectionDirective() + S->Name + getSectionFlags(S->Flags);
}
// Lame default implementation. Calculate the section name for global.
@@ -376,3 +376,16 @@
return &S;
}
+
+const std::string&
+TargetAsmInfo::getSectionFlags(unsigned Flags) const {
+ SectionFlags::FlagsStringsMapType::iterator I = FlagsStrings.find(Flags);
+
+ // We didn't print these flags yet, print and save them to map. This reduces
+ // amount of heap trashing due to std::string construction / concatenation.
+ if (I == FlagsStrings.end())
+ I = FlagsStrings.insert(std::make_pair(Flags,
+ printSectionFlags(Flags))).first;
+
+ return I->second;
+}
diff --git a/lib/Target/X86/X86TargetAsmInfo.cpp b/lib/Target/X86/X86TargetAsmInfo.cpp
index 984c6b2..178aec0 100644
--- a/lib/Target/X86/X86TargetAsmInfo.cpp
+++ b/lib/Target/X86/X86TargetAsmInfo.cpp
@@ -404,7 +404,7 @@
}
}
-std::string X86COFFTargetAsmInfo::PrintSectionFlags(unsigned flags) const {
+std::string X86COFFTargetAsmInfo::printSectionFlags(unsigned flags) const {
std::string Flags = ",\"";
if (flags & SectionFlags::Code)
diff --git a/lib/Target/X86/X86TargetAsmInfo.h b/lib/Target/X86/X86TargetAsmInfo.h
index 0c30545..d7e11e0 100644
--- a/lib/Target/X86/X86TargetAsmInfo.h
+++ b/lib/Target/X86/X86TargetAsmInfo.h
@@ -52,7 +52,7 @@
bool Global) const;
virtual std::string UniqueSectionForGlobal(const GlobalValue* GV,
SectionKind::Kind kind) const;
- virtual std::string PrintSectionFlags(unsigned flags) const;
+ virtual std::string printSectionFlags(unsigned flags) const;
protected:
const X86TargetMachine *X86TM;
};