Inline addRegular into addSymbol.
Because addRegular's functionality is tightly coupled with
addSymbol, and the former is called only once, it makes sense
to merge the two functions. This patch also adds comments.
llvm-svn: 315401
diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 4e8ee8b..14861d9 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -79,25 +79,6 @@
return getValue() - getSecAddr();
}
-static SymbolBody *addRegular(SymbolAssignment *Cmd) {
- Symbol *Sym;
- uint8_t Visibility = Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT;
- std::tie(Sym, std::ignore) = Symtab->insert(Cmd->Name, /*Type*/ 0, Visibility,
- /*CanOmitFromDynSym*/ false,
- /*File*/ nullptr);
- Sym->Binding = STB_GLOBAL;
- ExprValue Value = Cmd->Expression();
- SectionBase *Sec = Value.isAbsolute() ? nullptr : Value.Sec;
-
- // We want to set symbol values early if we can. This allows us to use symbols
- // as variables in linker scripts. Doing so allows us to write expressions
- // like this: `alignment = 16; . = ALIGN(., alignment)`
- uint64_t SymValue = Value.Sec ? 0 : Value.getValue();
- replaceBody<DefinedRegular>(Sym, nullptr, Cmd->Name, /*IsLocal=*/false,
- Visibility, STT_NOTYPE, SymValue, 0, Sec);
- return Sym->body();
-}
-
OutputSection *LinkerScript::createOutputSection(StringRef Name,
StringRef Location) {
OutputSection *&SecRef = NameToOutputSection[Name];
@@ -127,34 +108,14 @@
error(Loc + ": unable to move location counter backward for: " +
CurAddressState->OutSec->Name);
Dot = Val;
+
// Update to location counter means update to section size.
if (InSec)
CurAddressState->OutSec->Size = Dot - CurAddressState->OutSec->Addr;
}
-// Sets value of a symbol. Two kinds of symbols are processed: synthetic
-// symbols, whose value is an offset from beginning of section and regular
-// symbols whose value is absolute.
-void LinkerScript::assignSymbol(SymbolAssignment *Cmd, bool InSec) {
- if (Cmd->Name == ".") {
- setDot(Cmd->Expression, Cmd->Location, InSec);
- return;
- }
-
- if (!Cmd->Sym)
- return;
-
- auto *Sym = cast<DefinedRegular>(Cmd->Sym);
- ExprValue V = Cmd->Expression();
- if (V.isAbsolute()) {
- Sym->Value = V.getValue();
- Sym->Section = nullptr;
- } else {
- Sym->Section = V.Sec;
- Sym->Value = V.getSectionOffset();
- }
-}
-
+// This function is called from processCommands, while we are
+// fixing the output section layout.
void LinkerScript::addSymbol(SymbolAssignment *Cmd) {
if (Cmd->Name == ".")
return;
@@ -165,7 +126,54 @@
if (Cmd->Provide && (!B || B->isDefined()))
return;
- Cmd->Sym = addRegular(Cmd);
+ // Define a symbol.
+ Symbol *Sym;
+ uint8_t Visibility = Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT;
+ std::tie(Sym, std::ignore) = Symtab->insert(Cmd->Name, /*Type*/ 0, Visibility,
+ /*CanOmitFromDynSym*/ false,
+ /*File*/ nullptr);
+ Sym->Binding = STB_GLOBAL;
+ ExprValue Value = Cmd->Expression();
+ SectionBase *Sec = Value.isAbsolute() ? nullptr : Value.Sec;
+
+ // When this function is called, section addresses have not been
+ // fixed yet. So, we may or may not know the value of the RHS
+ // expression.
+ //
+ // For example, if an expression is `x = 42`, we know x is always 42.
+ // However, if an expression is `x = .`, there's no way to know its
+ // value at the moment.
+ //
+ // We want to set symbol values early if we can. This allows us to
+ // use symbols as variables in linker scripts. Doing so allows us to
+ // write expressions like this: `alignment = 16; . = ALIGN(., alignment)`.
+ uint64_t SymValue = Value.Sec ? 0 : Value.getValue();
+
+ replaceBody<DefinedRegular>(Sym, nullptr, Cmd->Name, /*IsLocal=*/false,
+ Visibility, STT_NOTYPE, SymValue, 0, Sec);
+ Cmd->Sym = cast<DefinedRegular>(Sym->body());
+}
+
+// This function is called from assignAddresses, while we are
+// fixing the output section addresses. This function is supposed
+// to set the final value for a given symbol assignment.
+void LinkerScript::assignSymbol(SymbolAssignment *Cmd, bool InSec) {
+ if (Cmd->Name == ".") {
+ setDot(Cmd->Expression, Cmd->Location, InSec);
+ return;
+ }
+
+ if (!Cmd->Sym)
+ return;
+
+ ExprValue V = Cmd->Expression();
+ if (V.isAbsolute()) {
+ Cmd->Sym->Section = nullptr;
+ Cmd->Sym->Value = V.getValue();
+ } else {
+ Cmd->Sym->Section = V.Sec;
+ Cmd->Sym->Value = V.getSectionOffset();
+ }
}
bool SymbolAssignment::classof(const BaseCommand *C) {
@@ -359,6 +367,7 @@
Aether = make<OutputSection>("", 0, SHF_ALLOC);
Aether->SectionIndex = 1;
auto State = make_unique<AddressState>(Opt);
+
// CurAddressState captures the local AddressState and makes it accessible
// deliberately. This is needed as there are some cases where we cannot just
// thread the current state through to a lambda function created by the
@@ -785,6 +794,7 @@
// -image-base if set.
Dot = Config->ImageBase ? *Config->ImageBase : 0;
auto State = make_unique<AddressState>(Opt);
+
// CurAddressState captures the local AddressState and makes it accessible
// deliberately. This is needed as there are some cases where we cannot just
// thread the current state through to a lambda function created by the