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-rw-r--r--ELF/ScriptParser.cpp304
1 files changed, 221 insertions, 83 deletions
diff --git a/ELF/ScriptParser.cpp b/ELF/ScriptParser.cpp
index 4263944981f2d..ddb4a49a3e5e6 100644
--- a/ELF/ScriptParser.cpp
+++ b/ELF/ScriptParser.cpp
@@ -63,6 +63,7 @@ private:
void readExtern();
void readGroup();
void readInclude();
+ void readInput();
void readMemory();
void readOutput();
void readOutputArch();
@@ -74,12 +75,14 @@ private:
void readVersion();
void readVersionScriptCommand();
- SymbolAssignment *readAssignment(StringRef Name);
+ SymbolAssignment *readSymbolAssignment(StringRef Name);
ByteCommand *readByteCommand(StringRef Tok);
uint32_t readFill();
uint32_t parseFill(StringRef Tok);
void readSectionAddressType(OutputSection *Cmd);
+ OutputSection *readOverlaySectionDescription();
OutputSection *readOutputSectionDescription(StringRef OutSec);
+ std::vector<BaseCommand *> readOverlay();
std::vector<StringRef> readOutputSectionPhdrs();
InputSectionDescription *readInputSectionDescription(StringRef Tok);
StringMatcher readFilePatterns();
@@ -88,16 +91,16 @@ private:
unsigned readPhdrType();
SortSectionPolicy readSortKind();
SymbolAssignment *readProvideHidden(bool Provide, bool Hidden);
- SymbolAssignment *readProvideOrAssignment(StringRef Tok);
+ SymbolAssignment *readAssignment(StringRef Tok);
void readSort();
- AssertCommand *readAssert();
- Expr readAssertExpr();
+ Expr readAssert();
Expr readConstant();
Expr getPageSize();
uint64_t readMemoryAssignment(StringRef, StringRef, StringRef);
std::pair<uint32_t, uint32_t> readMemoryAttributes();
+ Expr combine(StringRef Op, Expr L, Expr R);
Expr readExpr();
Expr readExpr1(Expr Lhs, int MinPrec);
StringRef readParenLiteral();
@@ -157,17 +160,6 @@ static ExprValue sub(ExprValue A, ExprValue B) {
return {A.Sec, false, A.getSectionOffset() - B.getValue(), A.Loc};
}
-static ExprValue mul(ExprValue A, ExprValue B) {
- return A.getValue() * B.getValue();
-}
-
-static ExprValue div(ExprValue A, ExprValue B) {
- if (uint64_t BV = B.getValue())
- return A.getValue() / BV;
- error("division by zero");
- return 0;
-}
-
static ExprValue bitAnd(ExprValue A, ExprValue B) {
moveAbsRight(A, B);
return {A.Sec, A.ForceAbsolute,
@@ -237,16 +229,16 @@ void ScriptParser::readLinkerScript() {
if (Tok == ";")
continue;
- if (Tok == "ASSERT") {
- Script->SectionCommands.push_back(readAssert());
- } else if (Tok == "ENTRY") {
+ if (Tok == "ENTRY") {
readEntry();
} else if (Tok == "EXTERN") {
readExtern();
- } else if (Tok == "GROUP" || Tok == "INPUT") {
+ } else if (Tok == "GROUP") {
readGroup();
} else if (Tok == "INCLUDE") {
readInclude();
+ } else if (Tok == "INPUT") {
+ readInput();
} else if (Tok == "MEMORY") {
readMemory();
} else if (Tok == "OUTPUT") {
@@ -265,7 +257,7 @@ void ScriptParser::readLinkerScript() {
readSections();
} else if (Tok == "VERSION") {
readVersion();
- } else if (SymbolAssignment *Cmd = readProvideOrAssignment(Tok)) {
+ } else if (SymbolAssignment *Cmd = readAssignment(Tok)) {
Script->SectionCommands.push_back(Cmd);
} else {
setError("unknown directive: " + Tok);
@@ -336,13 +328,12 @@ void ScriptParser::readExtern() {
}
void ScriptParser::readGroup() {
- expect("(");
- while (!errorCount() && !consume(")")) {
- if (consume("AS_NEEDED"))
- readAsNeeded();
- else
- addFile(unquote(next()));
- }
+ bool Orig = InputFile::IsInGroup;
+ InputFile::IsInGroup = true;
+ readInput();
+ InputFile::IsInGroup = Orig;
+ if (!Orig)
+ ++InputFile::NextGroupId;
}
void ScriptParser::readInclude() {
@@ -353,7 +344,7 @@ void ScriptParser::readInclude() {
return;
}
- if (Optional<std::string> Path = searchLinkerScript(Tok)) {
+ if (Optional<std::string> Path = searchScript(Tok)) {
if (Optional<MemoryBufferRef> MB = readFile(*Path))
tokenize(*MB);
return;
@@ -361,6 +352,16 @@ void ScriptParser::readInclude() {
setError("cannot find linker script " + Tok);
}
+void ScriptParser::readInput() {
+ expect("(");
+ while (!errorCount() && !consume(")")) {
+ if (consume("AS_NEEDED"))
+ readAsNeeded();
+ else
+ addFile(unquote(next()));
+ }
+}
+
void ScriptParser::readOutput() {
// -o <file> takes predecence over OUTPUT(<file>).
expect("(");
@@ -437,6 +438,49 @@ void ScriptParser::readSearchDir() {
expect(")");
}
+// This reads an overlay description. Overlays are used to describe output
+// sections that use the same virtual memory range and normally would trigger
+// linker's sections sanity check failures.
+// https://sourceware.org/binutils/docs/ld/Overlay-Description.html#Overlay-Description
+std::vector<BaseCommand *> ScriptParser::readOverlay() {
+ // VA and LMA expressions are optional, though for simplicity of
+ // implementation we assume they are not. That is what OVERLAY was designed
+ // for first of all: to allow sections with overlapping VAs at different LMAs.
+ Expr AddrExpr = readExpr();
+ expect(":");
+ expect("AT");
+ Expr LMAExpr = readParenExpr();
+ expect("{");
+
+ std::vector<BaseCommand *> V;
+ OutputSection *Prev = nullptr;
+ while (!errorCount() && !consume("}")) {
+ // VA is the same for all sections. The LMAs are consecutive in memory
+ // starting from the base load address specified.
+ OutputSection *OS = readOverlaySectionDescription();
+ OS->AddrExpr = AddrExpr;
+ if (Prev)
+ OS->LMAExpr = [=] { return Prev->getLMA() + Prev->Size; };
+ else
+ OS->LMAExpr = LMAExpr;
+ V.push_back(OS);
+ Prev = OS;
+ }
+
+ // According to the specification, at the end of the overlay, the location
+ // counter should be equal to the overlay base address plus size of the
+ // largest section seen in the overlay.
+ // Here we want to create the Dot assignment command to achieve that.
+ Expr MoveDot = [=] {
+ uint64_t Max = 0;
+ for (BaseCommand *Cmd : V)
+ Max = std::max(Max, cast<OutputSection>(Cmd)->Size);
+ return AddrExpr().getValue() + Max;
+ };
+ V.push_back(make<SymbolAssignment>(".", MoveDot, getCurrentLocation()));
+ return V;
+}
+
void ScriptParser::readSections() {
Script->HasSectionsCommand = true;
@@ -446,26 +490,48 @@ void ScriptParser::readSections() {
Config->SingleRoRx = true;
expect("{");
+ std::vector<BaseCommand *> V;
while (!errorCount() && !consume("}")) {
StringRef Tok = next();
- BaseCommand *Cmd = readProvideOrAssignment(Tok);
- if (!Cmd) {
- if (Tok == "ASSERT")
- Cmd = readAssert();
- else
- Cmd = readOutputSectionDescription(Tok);
+ if (Tok == "OVERLAY") {
+ for (BaseCommand *Cmd : readOverlay())
+ V.push_back(Cmd);
+ continue;
}
- Script->SectionCommands.push_back(Cmd);
+
+ if (BaseCommand *Cmd = readAssignment(Tok))
+ V.push_back(Cmd);
+ else
+ V.push_back(readOutputSectionDescription(Tok));
+ }
+
+ if (!atEOF() && consume("INSERT")) {
+ std::vector<BaseCommand *> *Dest = nullptr;
+ if (consume("AFTER"))
+ Dest = &Script->InsertAfterCommands[next()];
+ else if (consume("BEFORE"))
+ Dest = &Script->InsertBeforeCommands[next()];
+ else
+ setError("expected AFTER/BEFORE, but got '" + next() + "'");
+ if (Dest)
+ Dest->insert(Dest->end(), V.begin(), V.end());
+ return;
}
+
+ Script->SectionCommands.insert(Script->SectionCommands.end(), V.begin(),
+ V.end());
}
static int precedence(StringRef Op) {
return StringSwitch<int>(Op)
- .Cases("*", "/", 5)
- .Cases("+", "-", 4)
- .Cases("<<", ">>", 3)
- .Cases("<", "<=", ">", ">=", "==", "!=", 2)
- .Cases("&", "|", 1)
+ .Cases("*", "/", "%", 8)
+ .Cases("+", "-", 7)
+ .Cases("<<", ">>", 6)
+ .Cases("<", "<=", ">", ">=", "==", "!=", 5)
+ .Case("&", 4)
+ .Case("|", 3)
+ .Case("&&", 2)
+ .Case("||", 1)
.Default(-1);
}
@@ -588,11 +654,7 @@ void ScriptParser::readSort() {
expect(")");
}
-AssertCommand *ScriptParser::readAssert() {
- return make<AssertCommand>(readAssertExpr());
-}
-
-Expr ScriptParser::readAssertExpr() {
+Expr ScriptParser::readAssert() {
expect("(");
Expr E = readExpr();
expect(",");
@@ -617,12 +679,14 @@ uint32_t ScriptParser::readFill() {
return V;
}
-// Reads an expression and/or the special directive "(NOLOAD)" for an
-// output section definition.
+// Reads an expression and/or the special directive for an output
+// section definition. Directive is one of following: "(NOLOAD)",
+// "(COPY)", "(INFO)" or "(OVERLAY)".
//
// An output section name can be followed by an address expression
-// and/or by "(NOLOAD)". This grammar is not LL(1) because "(" can be
-// interpreted as either the beginning of some expression or "(NOLOAD)".
+// and/or directive. This grammar is not LL(1) because "(" can be
+// interpreted as either the beginning of some expression or beginning
+// of directive.
//
// https://sourceware.org/binutils/docs/ld/Output-Section-Address.html
// https://sourceware.org/binutils/docs/ld/Output-Section-Type.html
@@ -633,6 +697,11 @@ void ScriptParser::readSectionAddressType(OutputSection *Cmd) {
Cmd->Noload = true;
return;
}
+ if (consume("COPY") || consume("INFO") || consume("OVERLAY")) {
+ expect(")");
+ Cmd->NonAlloc = true;
+ return;
+ }
Cmd->AddrExpr = readExpr();
expect(")");
} else {
@@ -657,10 +726,23 @@ static Expr checkAlignment(Expr E, std::string &Loc) {
};
}
+OutputSection *ScriptParser::readOverlaySectionDescription() {
+ OutputSection *Cmd =
+ Script->createOutputSection(next(), getCurrentLocation());
+ Cmd->InOverlay = true;
+ expect("{");
+ while (!errorCount() && !consume("}"))
+ Cmd->SectionCommands.push_back(readInputSectionRules(next()));
+ Cmd->Phdrs = readOutputSectionPhdrs();
+ return Cmd;
+}
+
OutputSection *ScriptParser::readOutputSectionDescription(StringRef OutSec) {
OutputSection *Cmd =
Script->createOutputSection(OutSec, getCurrentLocation());
+ size_t SymbolsReferenced = Script->ReferencedSymbols.size();
+
if (peek() != ":")
readSectionAddressType(Cmd);
expect(":");
@@ -684,13 +766,10 @@ OutputSection *ScriptParser::readOutputSectionDescription(StringRef OutSec) {
StringRef Tok = next();
if (Tok == ";") {
// Empty commands are allowed. Do nothing here.
- } else if (SymbolAssignment *Assign = readProvideOrAssignment(Tok)) {
+ } else if (SymbolAssignment *Assign = readAssignment(Tok)) {
Cmd->SectionCommands.push_back(Assign);
} else if (ByteCommand *Data = readByteCommand(Tok)) {
Cmd->SectionCommands.push_back(Data);
- } else if (Tok == "ASSERT") {
- Cmd->SectionCommands.push_back(readAssert());
- expect(";");
} else if (Tok == "CONSTRUCTORS") {
// CONSTRUCTORS is a keyword to make the linker recognize C++ ctors/dtors
// by name. This is for very old file formats such as ECOFF/XCOFF.
@@ -709,6 +788,14 @@ OutputSection *ScriptParser::readOutputSectionDescription(StringRef OutSec) {
if (consume(">"))
Cmd->MemoryRegionName = next();
+ if (consume("AT")) {
+ expect(">");
+ Cmd->LMARegionName = next();
+ }
+
+ if (Cmd->LMAExpr && !Cmd->LMARegionName.empty())
+ error("section can't have both LMA and a load region");
+
Cmd->Phdrs = readOutputSectionPhdrs();
if (consume("="))
@@ -719,6 +806,8 @@ OutputSection *ScriptParser::readOutputSectionDescription(StringRef OutSec) {
// Consume optional comma following output section command.
consume(",");
+ if (Script->ReferencedSymbols.size() > SymbolsReferenced)
+ Cmd->ExpressionsUseSymbols = true;
return Cmd;
}
@@ -741,30 +830,39 @@ uint32_t ScriptParser::parseFill(StringRef Tok) {
SymbolAssignment *ScriptParser::readProvideHidden(bool Provide, bool Hidden) {
expect("(");
- SymbolAssignment *Cmd = readAssignment(next());
+ SymbolAssignment *Cmd = readSymbolAssignment(next());
Cmd->Provide = Provide;
Cmd->Hidden = Hidden;
expect(")");
- expect(";");
return Cmd;
}
-SymbolAssignment *ScriptParser::readProvideOrAssignment(StringRef Tok) {
+SymbolAssignment *ScriptParser::readAssignment(StringRef Tok) {
+ // Assert expression returns Dot, so this is equal to ".=."
+ if (Tok == "ASSERT")
+ return make<SymbolAssignment>(".", readAssert(), getCurrentLocation());
+
+ size_t OldPos = Pos;
SymbolAssignment *Cmd = nullptr;
- if (peek() == "=" || peek() == "+=") {
- Cmd = readAssignment(Tok);
- expect(";");
- } else if (Tok == "PROVIDE") {
+ if (peek() == "=" || peek() == "+=")
+ Cmd = readSymbolAssignment(Tok);
+ else if (Tok == "PROVIDE")
Cmd = readProvideHidden(true, false);
- } else if (Tok == "HIDDEN") {
+ else if (Tok == "HIDDEN")
Cmd = readProvideHidden(false, true);
- } else if (Tok == "PROVIDE_HIDDEN") {
+ else if (Tok == "PROVIDE_HIDDEN")
Cmd = readProvideHidden(true, true);
+
+ if (Cmd) {
+ Cmd->CommandString =
+ Tok.str() + " " +
+ llvm::join(Tokens.begin() + OldPos, Tokens.begin() + Pos, " ");
+ expect(";");
}
return Cmd;
}
-SymbolAssignment *ScriptParser::readAssignment(StringRef Name) {
+SymbolAssignment *ScriptParser::readSymbolAssignment(StringRef Name) {
StringRef Op = next();
assert(Op == "=" || Op == "+=");
Expr E = readExpr();
@@ -787,15 +885,31 @@ Expr ScriptParser::readExpr() {
return E;
}
-static Expr combine(StringRef Op, Expr L, Expr R) {
+Expr ScriptParser::combine(StringRef Op, Expr L, Expr R) {
if (Op == "+")
return [=] { return add(L(), R()); };
if (Op == "-")
return [=] { return sub(L(), R()); };
if (Op == "*")
- return [=] { return mul(L(), R()); };
- if (Op == "/")
- return [=] { return div(L(), R()); };
+ return [=] { return L().getValue() * R().getValue(); };
+ if (Op == "/") {
+ std::string Loc = getCurrentLocation();
+ return [=]() -> uint64_t {
+ if (uint64_t RV = R().getValue())
+ return L().getValue() / RV;
+ error(Loc + ": division by zero");
+ return 0;
+ };
+ }
+ if (Op == "%") {
+ std::string Loc = getCurrentLocation();
+ return [=]() -> uint64_t {
+ if (uint64_t RV = R().getValue())
+ return L().getValue() % RV;
+ error(Loc + ": modulo by zero");
+ return 0;
+ };
+ }
if (Op == "<<")
return [=] { return L().getValue() << R().getValue(); };
if (Op == ">>")
@@ -812,6 +926,10 @@ static Expr combine(StringRef Op, Expr L, Expr R) {
return [=] { return L().getValue() == R().getValue(); };
if (Op == "!=")
return [=] { return L().getValue() != R().getValue(); };
+ if (Op == "||")
+ return [=] { return L().getValue() || R().getValue(); };
+ if (Op == "&&")
+ return [=] { return L().getValue() && R().getValue(); };
if (Op == "&")
return [=] { return bitAnd(L(), R()); };
if (Op == "|")
@@ -865,20 +983,13 @@ Expr ScriptParser::readConstant() {
if (S == "MAXPAGESIZE")
return [] { return Config->MaxPageSize; };
setError("unknown constant: " + S);
- return {};
+ return [] { return 0; };
}
// Parses Tok as an integer. It recognizes hexadecimal (prefixed with
// "0x" or suffixed with "H") and decimal numbers. Decimal numbers may
// have "K" (Ki) or "M" (Mi) suffixes.
static Optional<uint64_t> parseInt(StringRef Tok) {
- // Negative number
- if (Tok.startswith("-")) {
- if (Optional<uint64_t> Val = parseInt(Tok.substr(1)))
- return -*Val;
- return None;
- }
-
// Hexadecimal
uint64_t Val;
if (Tok.startswith_lower("0x")) {
@@ -917,12 +1028,21 @@ ByteCommand *ScriptParser::readByteCommand(StringRef Tok) {
.Default(-1);
if (Size == -1)
return nullptr;
- return make<ByteCommand>(readParenExpr(), Size);
+
+ size_t OldPos = Pos;
+ Expr E = readParenExpr();
+ std::string CommandString =
+ Tok.str() + " " +
+ llvm::join(Tokens.begin() + OldPos, Tokens.begin() + Pos, " ");
+ return make<ByteCommand>(E, Size, CommandString);
}
StringRef ScriptParser::readParenLiteral() {
expect("(");
+ bool Orig = InExpr;
+ InExpr = false;
StringRef Tok = next();
+ InExpr = Orig;
expect(")");
return Tok;
}
@@ -995,7 +1115,7 @@ Expr ScriptParser::readPrimary() {
};
}
if (Tok == "ASSERT")
- return readAssertExpr();
+ return readAssert();
if (Tok == "CONSTANT")
return readConstant();
if (Tok == "DATA_SEGMENT_ALIGN") {
@@ -1032,8 +1152,10 @@ Expr ScriptParser::readPrimary() {
}
if (Tok == "LENGTH") {
StringRef Name = readParenLiteral();
- if (Script->MemoryRegions.count(Name) == 0)
+ if (Script->MemoryRegions.count(Name) == 0) {
setError("memory region not defined: " + Name);
+ return [] { return 0; };
+ }
return [=] { return Script->MemoryRegions[Name]->Length; };
}
if (Tok == "LOADADDR") {
@@ -1044,10 +1166,22 @@ Expr ScriptParser::readPrimary() {
return Cmd->getLMA();
};
}
+ if (Tok == "MAX" || Tok == "MIN") {
+ expect("(");
+ Expr A = readExpr();
+ expect(",");
+ Expr B = readExpr();
+ expect(")");
+ if (Tok == "MIN")
+ return [=] { return std::min(A().getValue(), B().getValue()); };
+ return [=] { return std::max(A().getValue(), B().getValue()); };
+ }
if (Tok == "ORIGIN") {
StringRef Name = readParenLiteral();
- if (Script->MemoryRegions.count(Name) == 0)
+ if (Script->MemoryRegions.count(Name) == 0) {
setError("memory region not defined: " + Name);
+ return [] { return 0; };
+ }
return [=] { return Script->MemoryRegions[Name]->Origin; };
}
if (Tok == "SEGMENT_START") {
@@ -1229,6 +1363,9 @@ ScriptParser::readSymbols() {
// Reads an "extern C++" directive, e.g.,
// "extern "C++" { ns::*; "f(int, double)"; };"
+//
+// The last semicolon is optional. E.g. this is OK:
+// "extern "C++" { ns::*; "f(int, double)" };"
std::vector<SymbolVersion> ScriptParser::readVersionExtern() {
StringRef Tok = next();
bool IsCXX = Tok == "\"C++\"";
@@ -1241,6 +1378,8 @@ std::vector<SymbolVersion> ScriptParser::readVersionExtern() {
StringRef Tok = next();
bool HasWildcard = !Tok.startswith("\"") && hasWildcard(Tok);
Ret.push_back({unquote(Tok), IsCXX, HasWildcard});
+ if (consume("}"))
+ return Ret;
expect(";");
}
@@ -1280,11 +1419,10 @@ void ScriptParser::readMemory() {
uint64_t Length = readMemoryAssignment("LENGTH", "len", "l");
// Add the memory region to the region map.
- if (Script->MemoryRegions.count(Name))
+ MemoryRegion *MR =
+ make<MemoryRegion>(Name, Origin, Length, Flags, NegFlags);
+ if (!Script->MemoryRegions.insert({Name, MR}).second)
setError("region '" + Name + "' already defined");
- MemoryRegion *MR = make<MemoryRegion>();
- *MR = {Name, Origin, Length, Flags, NegFlags};
- Script->MemoryRegions[Name] = MR;
}
}
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