[lld] r330874 - Pack symbols a bit more.
Rafael Espindola via llvm-commits
llvm-commits at lists.llvm.org
Wed Apr 25 14:44:37 PDT 2018
Author: rafael
Date: Wed Apr 25 14:44:37 2018
New Revision: 330874
URL: http://llvm.org/viewvc/llvm-project?rev=330874&view=rev
Log:
Pack symbols a bit more.
Before this patch:
Symbol 56
Defined 80
Undefined 56
SharedSymbol 88
LazyArchive 72
LazyObject 56
With this patch
Symbol 48
Defined 72
Undefined 48
SharedSymbol 80
LazyArchive 64
LazyObject 48
The result is that peak allocation when linking chromium (according to
heaptrack) goes from 578 to 568 MB.
Modified:
lld/trunk/ELF/Symbols.cpp
lld/trunk/ELF/Symbols.h
lld/trunk/include/lld/Common/Strings.h
Modified: lld/trunk/ELF/Symbols.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Symbols.cpp?rev=330874&r1=330873&r2=330874&view=diff
==============================================================================
--- lld/trunk/ELF/Symbols.cpp (original)
+++ lld/trunk/ELF/Symbols.cpp Wed Apr 25 14:44:37 2018
@@ -177,7 +177,7 @@ void Symbol::parseSymbolVersion() {
return;
// Truncate the symbol name so that it doesn't include the version string.
- Name = {S.data(), Pos};
+ NameSize = Pos;
// If this is not in this DSO, it is not a definition.
if (!isDefined())
Modified: lld/trunk/ELF/Symbols.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Symbols.h?rev=330874&r1=330873&r2=330874&view=diff
==============================================================================
--- lld/trunk/ELF/Symbols.h (original)
+++ lld/trunk/ELF/Symbols.h Wed Apr 25 14:44:37 2018
@@ -45,6 +45,23 @@ public:
Kind kind() const { return static_cast<Kind>(SymbolKind); }
+ // The file from which this symbol was created.
+ InputFile *File;
+
+protected:
+ const char *NameStart;
+ mutable uint32_t NameSize;
+
+public:
+ uint32_t DynsymIndex = 0;
+ uint32_t GotIndex = -1;
+ uint32_t GotPltIndex = -1;
+ uint32_t PltIndex = -1;
+ uint32_t GlobalDynIndex = -1;
+
+ // Version definition index.
+ uint16_t VersionId;
+
// Symbol binding. This is not overwritten by replaceSymbol to track
// changes during resolution. In particular:
// - An undefined weak is still weak when it resolves to a shared library.
@@ -52,8 +69,11 @@ public:
// remember it is weak.
uint8_t Binding;
- // Version definition index.
- uint16_t VersionId;
+ // The following fields have the same meaning as the ELF symbol attributes.
+ uint8_t Type; // symbol type
+ uint8_t StOther; // st_other field value
+
+ const uint8_t SymbolKind;
// Symbol visibility. This is the computed minimum visibility of all
// observed non-DSO symbols.
@@ -79,9 +99,6 @@ public:
// True if this symbol is specified by --trace-symbol option.
unsigned Traced : 1;
- // The file from which this symbol was created.
- InputFile *File;
-
bool includeInDynsym() const;
uint8_t computeBinding() const;
bool isWeak() const { return Binding == llvm::ELF::STB_WEAK; }
@@ -98,7 +115,11 @@ public:
// True if this is an undefined weak symbol.
bool isUndefWeak() const { return isWeak() && isUndefined(); }
- StringRef getName() const { return Name; }
+ StringRef getName() const {
+ if (NameSize == (uint32_t)-1)
+ NameSize = strlen(NameStart);
+ return StringRef(NameStart, NameSize);
+ }
void parseSymbolVersion();
bool isInGot() const { return GotIndex != -1U; }
@@ -114,21 +135,14 @@ public:
uint64_t getSize() const;
OutputSection *getOutputSection() const;
- uint32_t DynsymIndex = 0;
- uint32_t GotIndex = -1;
- uint32_t GotPltIndex = -1;
- uint32_t PltIndex = -1;
- uint32_t GlobalDynIndex = -1;
-
protected:
Symbol(Kind K, InputFile *File, StringRefZ Name, uint8_t Binding,
uint8_t StOther, uint8_t Type)
- : Binding(Binding), File(File), SymbolKind(K), NeedsPltAddr(false),
- IsInGlobalMipsGot(false), Is32BitMipsGot(false), IsInIplt(false),
- IsInIgot(false), IsPreemptible(false), Used(!Config->GcSections),
- Type(Type), StOther(StOther), Name(Name) {}
-
- const unsigned SymbolKind : 8;
+ : File(File), NameStart(Name.data()), NameSize(Name.rawSize()),
+ Binding(Binding), Type(Type), StOther(StOther), SymbolKind(K),
+ NeedsPltAddr(false), IsInGlobalMipsGot(false), Is32BitMipsGot(false),
+ IsInIplt(false), IsInIgot(false), IsPreemptible(false),
+ Used(!Config->GcSections) {}
public:
// True the symbol should point to its PLT entry.
@@ -152,10 +166,6 @@ public:
// True if an undefined or shared symbol is used from a live section.
unsigned Used : 1;
- // The following fields have the same meaning as the ELF symbol attributes.
- uint8_t Type; // symbol type
- uint8_t StOther; // st_other field value
-
// The Type field may also have this value. It means that we have not yet seen
// a non-Lazy symbol with this name, so we don't know what its type is. The
// Type field is normally set to this value for Lazy symbols unless we saw a
@@ -169,9 +179,6 @@ public:
bool isGnuIFunc() const { return Type == llvm::ELF::STT_GNU_IFUNC; }
bool isObject() const { return Type == llvm::ELF::STT_OBJECT; }
bool isFile() const { return Type == llvm::ELF::STT_FILE; }
-
-protected:
- StringRefZ Name;
};
// Represents a symbol that is defined in the current output file.
Modified: lld/trunk/include/lld/Common/Strings.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/include/lld/Common/Strings.h?rev=330874&r1=330873&r2=330874&view=diff
==============================================================================
--- lld/trunk/include/lld/Common/Strings.h (original)
+++ lld/trunk/include/lld/Common/Strings.h Wed Apr 25 14:44:37 2018
@@ -45,6 +45,9 @@ public:
/*implicit*/ StringRefZ(llvm::StringRef S)
: Start(S.data()), Size(S.size()) {}
+ const char *data() const { return Start; }
+ size_t rawSize() const { return Size; };
+
operator llvm::StringRef() const {
if (Size == (size_t)-1)
Size = strlen(Start);
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