Move name lookup to script parsing time.
We were looking up sections by name during expression evaluation. By
keeping track of forward declarations we can do the lookup during
script parsing.
Doing the lookup earlier will be more efficient when assignAddresses
is run twice and removes two uses of OutputSections.
llvm-svn: 304381
diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index eecbe9c..ec3f282 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -84,29 +84,28 @@
return Sym->body();
}
-OutputSection *LinkerScript::getOutputSection(const Twine &Loc,
- StringRef Name) {
- for (OutputSection *Sec : *OutputSections)
- if (Sec->Name == Name)
- return Sec;
-
- static OutputSection Dummy("", 0, 0);
- if (ErrorOnMissingSection)
- error(Loc + ": undefined section " + Name);
- return &Dummy;
+OutputSectionCommand *
+LinkerScript::createOutputSectionCommand(StringRef Name, StringRef Location) {
+ OutputSectionCommand *&CmdRef = NameToOutputSectionCommand[Name];
+ OutputSectionCommand *Cmd;
+ if (CmdRef && CmdRef->Location.empty()) {
+ // There was a forward reference.
+ Cmd = CmdRef;
+ } else {
+ Cmd = make<OutputSectionCommand>(Name);
+ if (!CmdRef)
+ CmdRef = Cmd;
+ }
+ Cmd->Location = Location;
+ return Cmd;
}
-// This function is essentially the same as getOutputSection(Name)->Size,
-// but it won't print out an error message if a given section is not found.
-//
-// Linker script does not create an output section if its content is empty.
-// We want to allow SIZEOF(.foo) where .foo is a section which happened to
-// be empty. That is why this function is different from getOutputSection().
-uint64_t LinkerScript::getOutputSectionSize(StringRef Name) {
- for (OutputSection *Sec : *OutputSections)
- if (Sec->Name == Name)
- return Sec->Size;
- return 0;
+OutputSectionCommand *
+LinkerScript::getOrCreateOutputSectionCommand(StringRef Name) {
+ OutputSectionCommand *&CmdRef = NameToOutputSectionCommand[Name];
+ if (!CmdRef)
+ CmdRef = make<OutputSectionCommand>(Name);
+ return CmdRef;
}
void LinkerScript::setDot(Expr E, const Twine &Loc, bool InSec) {
@@ -456,7 +455,7 @@
// For each OutputSection that needs a VA fabricate an OutputSectionCommand
// with an InputSectionDescription describing the InputSections
for (OutputSection *Sec : *OutputSections) {
- auto *OSCmd = make<OutputSectionCommand>(Sec->Name);
+ auto *OSCmd = createOutputSectionCommand(Sec->Name, "<internal>");
OSCmd->Sec = Sec;
SecToCommand[Sec] = OSCmd;
@@ -843,7 +842,7 @@
// representations agree on which input sections to use.
OutputSectionCommand *Cmd = getCmd(Sec);
if (!Cmd) {
- Cmd = make<OutputSectionCommand>(Name);
+ Cmd = createOutputSectionCommand(Name, "<internal>");
Opt.Commands.insert(CmdIter, Cmd);
++CmdIndex;
diff --git a/lld/ELF/LinkerScript.h b/lld/ELF/LinkerScript.h
index 08f60f45..819d7c5 100644
--- a/lld/ELF/LinkerScript.h
+++ b/lld/ELF/LinkerScript.h
@@ -221,6 +221,8 @@
class LinkerScript final {
llvm::DenseMap<OutputSection *, OutputSectionCommand *> SecToCommand;
+ llvm::DenseMap<StringRef, OutputSectionCommand *> NameToOutputSectionCommand;
+
void assignSymbol(SymbolAssignment *Cmd, bool InSec);
void setDot(Expr E, const Twine &Loc, bool InSec);
@@ -241,7 +243,6 @@
void process(BaseCommand &Base);
OutputSection *Aether;
- bool ErrorOnMissingSection = false;
uint64_t Dot;
uint64_t ThreadBssOffset = 0;
@@ -251,11 +252,14 @@
MemoryRegion *CurMemRegion = nullptr;
public:
+ bool ErrorOnMissingSection = false;
+ OutputSectionCommand *createOutputSectionCommand(StringRef Name,
+ StringRef Location);
+ OutputSectionCommand *getOrCreateOutputSectionCommand(StringRef Name);
+
OutputSectionCommand *getCmd(OutputSection *Sec) const;
bool hasPhdrsCommands() { return !Opt.PhdrsCommands.empty(); }
uint64_t getDot() { return Dot; }
- OutputSection *getOutputSection(const Twine &Loc, StringRef S);
- uint64_t getOutputSectionSize(StringRef S);
void discard(ArrayRef<InputSectionBase *> V);
ExprValue getSymbolValue(const Twine &Loc, StringRef S);
diff --git a/lld/ELF/ScriptParser.cpp b/lld/ELF/ScriptParser.cpp
index 4b77e35..02212fa 100644
--- a/lld/ELF/ScriptParser.cpp
+++ b/lld/ELF/ScriptParser.cpp
@@ -55,6 +55,7 @@
private:
void addFile(StringRef Path);
+ OutputSection *checkSection(OutputSectionCommand *Cmd, StringRef Loccation);
void readAsNeeded();
void readEntry();
@@ -564,8 +565,8 @@
OutputSectionCommand *
ScriptParser::readOutputSectionDescription(StringRef OutSec) {
- OutputSectionCommand *Cmd = make<OutputSectionCommand>(OutSec);
- Cmd->Location = getCurrentLocation();
+ OutputSectionCommand *Cmd =
+ Script->createOutputSectionCommand(OutSec, getCurrentLocation());
// Read an address expression.
// https://sourceware.org/binutils/docs/ld/Output-Section-Address.html
@@ -819,6 +820,16 @@
return Tok;
}
+OutputSection *ScriptParser::checkSection(OutputSectionCommand *Cmd,
+ StringRef Location) {
+ if (Cmd->Location.empty() && Script->ErrorOnMissingSection)
+ error(Location + ": undefined section " + Cmd->Name);
+ if (Cmd->Sec)
+ return Cmd->Sec;
+ static OutputSection Dummy("", 0, 0);
+ return &Dummy;
+}
+
Expr ScriptParser::readPrimary() {
if (peek() == "(")
return readParenExpr();
@@ -847,9 +858,8 @@
}
if (Tok == "ADDR") {
StringRef Name = readParenLiteral();
- return [=]() -> ExprValue {
- return {Script->getOutputSection(Location, Name), 0};
- };
+ OutputSectionCommand *Cmd = Script->getOrCreateOutputSectionCommand(Name);
+ return [=]() -> ExprValue { return {checkSection(Cmd, Location), 0}; };
}
if (Tok == "ALIGN") {
expect("(");
@@ -867,7 +877,8 @@
}
if (Tok == "ALIGNOF") {
StringRef Name = readParenLiteral();
- return [=] { return Script->getOutputSection(Location, Name)->Alignment; };
+ OutputSectionCommand *Cmd = Script->getOrCreateOutputSectionCommand(Name);
+ return [=] { return checkSection(Cmd, Location)->Alignment; };
}
if (Tok == "ASSERT")
return readAssertExpr();
@@ -912,7 +923,8 @@
}
if (Tok == "LOADADDR") {
StringRef Name = readParenLiteral();
- return [=] { return Script->getOutputSection(Location, Name)->getLMA(); };
+ OutputSectionCommand *Cmd = Script->getOrCreateOutputSectionCommand(Name);
+ return [=] { return checkSection(Cmd, Location)->getLMA(); };
}
if (Tok == "ORIGIN") {
StringRef Name = readParenLiteral();
@@ -930,7 +942,11 @@
}
if (Tok == "SIZEOF") {
StringRef Name = readParenLiteral();
- return [=] { return Script->getOutputSectionSize(Name); };
+ OutputSectionCommand *Cmd = Script->getOrCreateOutputSectionCommand(Name);
+ // Linker script does not create an output section if its content is empty.
+ // We want to allow SIZEOF(.foo) where .foo is a section which happened to
+ // be empty.
+ return [=] { return Cmd->Sec ? Cmd->Sec->Size : 0; };
}
if (Tok == "SIZEOF_HEADERS")
return [=] { return elf::getHeaderSize(); };