ELF symbol table field st_other support,
excluding visibility bits.
Generic STO handling at the Target level.
The st_other field of the ELF symbol table is one
byte in size. The first 2 bytes are used for generic
visibility and are currently handled by llvm.
The other six bits are processor specific and need
to be set at the target level.
A couple of notes:
The new static methods for accessing and setting the "other"
flags in include/llvm/MC/MCELF.h match the style guide
and not the other methods in the file. I don't like the
inconsistency, but feel I should follow the prescribed
lowerUpper() convention.
STO_ value definitions are not specified in gnu land as
consistently as the STT_ and STB_ fields. Probably because
the latter were defined in a standards doc and the former
defined partially in code. I have stuck with the full byte
definition of the flags.
Contributer: Zoran Jovanovic
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175561 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index fb14dc9..0b97f27 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -546,12 +546,17 @@
bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() ||
Data.getSymbol().isVariable();
+ // Binding and Type share the same byte as upper and lower nibbles
uint8_t Binding = MCELF::GetBinding(OrigData);
- uint8_t Visibility = MCELF::GetVisibility(OrigData);
uint8_t Type = MCELF::GetType(Data);
-
uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift);
- uint8_t Other = Visibility;
+
+ // Other and Visibility share the same byte with Visability using the lower
+ // 2 bits
+ uint8_t Visibility = MCELF::GetVisibility(OrigData);
+ uint8_t Other = MCELF::getOther(OrigData) <<
+ (ELF_Other_Shift - ELF_STV_Shift);
+ Other |= Visibility;
uint64_t Value = SymbolValue(Data, Layout);
uint64_t Size = 0;
diff --git a/lib/MC/MCELF.cpp b/lib/MC/MCELF.cpp
index 4db2846..560cdbc 100644
--- a/lib/MC/MCELF.cpp
+++ b/lib/MC/MCELF.cpp
@@ -52,6 +52,8 @@
return Type;
}
+// Visibility is stored in the first two bits of st_other
+// st_other values are stored in the second byte of get/setFlags
void MCELF::SetVisibility(MCSymbolData &SD, unsigned Visibility) {
assert(Visibility == ELF::STV_DEFAULT || Visibility == ELF::STV_INTERNAL ||
Visibility == ELF::STV_HIDDEN || Visibility == ELF::STV_PROTECTED);
@@ -68,4 +70,17 @@
return Visibility;
}
+// Other is stored in the last six bits of st_other
+// st_other values are stored in the second byte of get/setFlags
+void MCELF::setOther(MCSymbolData &SD, unsigned Other) {
+ uint32_t OtherFlags = SD.getFlags() & ~(0x3f << ELF_Other_Shift);
+ SD.setFlags(OtherFlags | (Other << ELF_Other_Shift));
+}
+
+unsigned MCELF::getOther(MCSymbolData &SD) {
+ unsigned Other =
+ (SD.getFlags() & (0x3f << ELF_Other_Shift)) >> ELF_Other_Shift;
+ return Other;
+}
+
}
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index 8ddbfbb..a9c35cc 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -504,6 +504,10 @@
llvm_unreachable("Generic ELF doesn't support this directive");
}
+MCSymbolData &MCELFStreamer::getOrCreateSymbolData(MCSymbol *Symbol) {
+ return getAssembler().getOrCreateSymbolData(*Symbol);
+}
+
void MCELFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
llvm_unreachable("ELF doesn't support this directive");
}
diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp
index 7d79d62..9857f7b 100644
--- a/lib/MC/MCStreamer.cpp
+++ b/lib/MC/MCStreamer.cpp
@@ -620,3 +620,8 @@
FinishImpl();
}
+
+MCSymbolData &MCStreamer::getOrCreateSymbolData(MCSymbol *Symbol) {
+ report_fatal_error("Not supported!");
+ return *(static_cast<MCSymbolData*> (NULL));
+}