[llvm-commits] CVS: llvm/include/llvm/CodeGen/ELFWriter.h
Chris Lattner
lattner at cs.uiuc.edu
Sat Jul 16 01:01:09 PDT 2005
Changes in directory llvm/include/llvm/CodeGen:
ELFWriter.h updated: 1.7 -> 1.8
---
Log message:
Major refactor of the ELFWriter code. Instead of building up one big
vector that represents the .o file at once, build up a vector for each
section of the .o file. This is needed because the .o file writer needs
to be able to switch between sections as it emits them (e.g. switch
between the .text section and the .rel section when emitting code).
This patch has no functionality change.
---
Diffs of the changes: (+97 -63)
ELFWriter.h | 160 ++++++++++++++++++++++++++++++++++++------------------------
1 files changed, 97 insertions(+), 63 deletions(-)
Index: llvm/include/llvm/CodeGen/ELFWriter.h
diff -u llvm/include/llvm/CodeGen/ELFWriter.h:1.7 llvm/include/llvm/CodeGen/ELFWriter.h:1.8
--- llvm/include/llvm/CodeGen/ELFWriter.h:1.7 Tue Jul 12 01:57:26 2005
+++ llvm/include/llvm/CodeGen/ELFWriter.h Sat Jul 16 03:00:57 2005
@@ -15,6 +15,7 @@
#define LLVM_CODEGEN_ELFWRITER_H
#include "llvm/CodeGen/MachineFunctionPass.h"
+#include <list>
namespace llvm {
class GlobalVariable;
@@ -35,6 +36,8 @@
~ELFWriter();
+ typedef std::vector<unsigned char> DataBuffer;
+
protected:
ELFWriter(std::ostream &O, TargetMachine &TM);
@@ -85,14 +88,14 @@
bool doFinalization(Module &M);
private:
- // The buffer we are accumulating the file into. Note that this should be
+ // The buffer we accumulate the file header into. Note that this should be
// changed into something much more efficient later (and the bytecode writer
// as well!).
- std::vector<unsigned char> OutputBuffer;
+ DataBuffer FileHeader;
/// ELFSection - This struct contains information about each section that is
- /// emitted to the OutputBuffer. This is eventually turned into the section
- /// header table at the end of the file.
+ /// emitted to the file. This is eventually turned into the section header
+ /// table at the end of the file.
struct ELFSection {
std::string Name; // Name of the section.
unsigned NameIdx; // Index in .shstrtab of name, once emitted.
@@ -106,6 +109,14 @@
unsigned Align;
unsigned EntSize;
+ /// SectionIdx - The number of the section in the Section Table.
+ ///
+ unsigned short SectionIdx;
+
+ /// SectionData - The actual data for this section which we are building
+ /// up for emission to the file.
+ DataBuffer SectionData;
+
enum { SHT_NULL = 0, SHT_PROGBITS = 1, SHT_SYMTAB = 2, SHT_STRTAB = 3,
SHT_RELA = 4, SHT_HASH = 5, SHT_DYNAMIC = 6, SHT_NOTE = 7,
SHT_NOBITS = 8, SHT_REL = 9, SHT_SHLIB = 10, SHT_DYNSYM = 11 };
@@ -123,8 +134,8 @@
SHF_TLS = 1 << 10,// Section holds thread-local data
};
- ELFSection(const char *name = "", unsigned offset = 0)
- : Name(name), Type(0), Flags(0), Addr(0), Offset(offset), Size(0),
+ ELFSection(const std::string &name)
+ : Name(name), Type(0), Flags(0), Addr(0), Offset(0), Size(0),
Link(0), Info(0), Align(0), EntSize(0) {
}
};
@@ -132,7 +143,24 @@
/// SectionList - This is the list of sections that we have emitted to the
/// file. Once the file has been completely built, the section header table
/// is constructed from this info.
- std::vector<ELFSection> SectionList;
+ std::list<ELFSection> SectionList;
+ unsigned NumSections; // Always = SectionList.size()
+
+ /// SectionLookup - This is a mapping from section name to section number in
+ /// the SectionList.
+ std::map<std::string, ELFSection*> SectionLookup;
+
+ /// getSection - Return the section with the specified name, creating a new
+ /// section if one does not already exist.
+ ELFSection &getSection(const std::string &Name) {
+ ELFSection *&SN = SectionLookup[Name];
+ if (SN) return *SN;
+
+ SectionList.push_back(Name);
+ SN = &SectionList.back();
+ SN->SectionIdx = NumSections++;
+ return *SN;
+ }
/// ELFSym - This struct contains information about each symbol that is
/// added to logical symbol table for the module. This is eventually
@@ -163,103 +191,109 @@
};
/// SymbolTable - This is the list of symbols we have emitted to the file.
- /// This actually gets rearranged before emission to OutputBuffer (to put
- /// the local symbols first in the list).
+ /// This actually gets rearranged before emission to the file (to put the
+ /// local symbols first in the list).
std::vector<ELFSym> SymbolTable;
- // As we accumulate the ELF file into OutputBuffer, we occasionally need to
- // keep track of locations to update later (e.g. the location of the section
- // table in the ELF header. These members keep track of the offset in
- // OffsetBuffer of these various pieces to update and other locations in the
- // file.
+ // As we complete the ELF file, we need to update fields in the ELF header
+ // (e.g. the location of the section table). These members keep track of
+ // the offset in ELFHeader of these various pieces to update and other
+ // locations in the file.
unsigned ELFHeader_e_shoff_Offset; // e_shoff in ELF header.
unsigned ELFHeader_e_shstrndx_Offset; // e_shstrndx in ELF header.
unsigned ELFHeader_e_shnum_Offset; // e_shnum in ELF header.
+
// align - Emit padding into the file until the current output position is
// aligned to the specified power of two boundary.
- void align(unsigned Boundary) {
+ static void align(DataBuffer &Output, unsigned Boundary) {
assert(Boundary && (Boundary & (Boundary-1)) == 0 &&
"Must align to 2^k boundary");
- while (OutputBuffer.size() & (Boundary-1))
- outbyte(0xAB);
+ size_t Size = Output.size();
+ if (Size & (Boundary-1)) {
+ // Add padding to get alignment to the correct place.
+ size_t Pad = Boundary-(Size & (Boundary-1));
+ Output.resize(Size+Pad);
+ }
}
- void outbyte(unsigned char X) { OutputBuffer.push_back(X); }
- void outhalf(unsigned short X) {
+ static void outbyte(DataBuffer &Output, unsigned char X) {
+ Output.push_back(X);
+ }
+ void outhalf(DataBuffer &Output, unsigned short X) {
if (isLittleEndian) {
- OutputBuffer.push_back(X&255);
- OutputBuffer.push_back(X >> 8);
+ Output.push_back(X&255);
+ Output.push_back(X >> 8);
} else {
- OutputBuffer.push_back(X >> 8);
- OutputBuffer.push_back(X&255);
+ Output.push_back(X >> 8);
+ Output.push_back(X&255);
}
}
- void outword(unsigned X) {
+ void outword(DataBuffer &Output, unsigned X) {
if (isLittleEndian) {
- OutputBuffer.push_back((X >> 0) & 255);
- OutputBuffer.push_back((X >> 8) & 255);
- OutputBuffer.push_back((X >> 16) & 255);
- OutputBuffer.push_back((X >> 24) & 255);
+ Output.push_back((X >> 0) & 255);
+ Output.push_back((X >> 8) & 255);
+ Output.push_back((X >> 16) & 255);
+ Output.push_back((X >> 24) & 255);
} else {
- OutputBuffer.push_back((X >> 24) & 255);
- OutputBuffer.push_back((X >> 16) & 255);
- OutputBuffer.push_back((X >> 8) & 255);
- OutputBuffer.push_back((X >> 0) & 255);
+ Output.push_back((X >> 24) & 255);
+ Output.push_back((X >> 16) & 255);
+ Output.push_back((X >> 8) & 255);
+ Output.push_back((X >> 0) & 255);
}
}
- void outxword(uint64_t X) {
+ void outxword(DataBuffer &Output, uint64_t X) {
if (isLittleEndian) {
- OutputBuffer.push_back((X >> 0) & 255);
- OutputBuffer.push_back((X >> 8) & 255);
- OutputBuffer.push_back((X >> 16) & 255);
- OutputBuffer.push_back((X >> 24) & 255);
- OutputBuffer.push_back((X >> 32) & 255);
- OutputBuffer.push_back((X >> 40) & 255);
- OutputBuffer.push_back((X >> 48) & 255);
- OutputBuffer.push_back((X >> 56) & 255);
+ Output.push_back((X >> 0) & 255);
+ Output.push_back((X >> 8) & 255);
+ Output.push_back((X >> 16) & 255);
+ Output.push_back((X >> 24) & 255);
+ Output.push_back((X >> 32) & 255);
+ Output.push_back((X >> 40) & 255);
+ Output.push_back((X >> 48) & 255);
+ Output.push_back((X >> 56) & 255);
} else {
- OutputBuffer.push_back((X >> 56) & 255);
- OutputBuffer.push_back((X >> 48) & 255);
- OutputBuffer.push_back((X >> 40) & 255);
- OutputBuffer.push_back((X >> 32) & 255);
- OutputBuffer.push_back((X >> 24) & 255);
- OutputBuffer.push_back((X >> 16) & 255);
- OutputBuffer.push_back((X >> 8) & 255);
- OutputBuffer.push_back((X >> 0) & 255);
+ Output.push_back((X >> 56) & 255);
+ Output.push_back((X >> 48) & 255);
+ Output.push_back((X >> 40) & 255);
+ Output.push_back((X >> 32) & 255);
+ Output.push_back((X >> 24) & 255);
+ Output.push_back((X >> 16) & 255);
+ Output.push_back((X >> 8) & 255);
+ Output.push_back((X >> 0) & 255);
}
}
- void outaddr32(unsigned X) {
- outword(X);
+ void outaddr32(DataBuffer &Output, unsigned X) {
+ outword(Output, X);
}
- void outaddr64(uint64_t X) {
- outxword(X);
+ void outaddr64(DataBuffer &Output, uint64_t X) {
+ outxword(Output, X);
}
- void outaddr(uint64_t X) {
+ void outaddr(DataBuffer &Output, uint64_t X) {
if (!is64Bit)
- outword((unsigned)X);
+ outword(Output, (unsigned)X);
else
- outxword(X);
+ outxword(Output, X);
}
// fix functions - Replace an existing entry at an offset.
- void fixhalf(unsigned short X, unsigned Offset) {
- unsigned char *P = &OutputBuffer[Offset];
+ void fixhalf(DataBuffer &Output, unsigned short X, unsigned Offset) {
+ unsigned char *P = &Output[Offset];
P[0] = (X >> (isLittleEndian ? 0 : 8)) & 255;
P[1] = (X >> (isLittleEndian ? 8 : 0)) & 255;
}
- void fixword(unsigned X, unsigned Offset) {
- unsigned char *P = &OutputBuffer[Offset];
+ void fixword(DataBuffer &Output, unsigned X, unsigned Offset) {
+ unsigned char *P = &Output[Offset];
P[0] = (X >> (isLittleEndian ? 0 : 24)) & 255;
P[1] = (X >> (isLittleEndian ? 8 : 16)) & 255;
P[2] = (X >> (isLittleEndian ? 16 : 8)) & 255;
P[3] = (X >> (isLittleEndian ? 24 : 0)) & 255;
}
- void fixaddr(uint64_t X, unsigned Offset) {
+ void fixaddr(DataBuffer &Output, uint64_t X, unsigned Offset) {
if (!is64Bit)
- fixword((unsigned)X, Offset);
+ fixword(Output, (unsigned)X, Offset);
else
assert(0 && "Emission of 64-bit data not implemented yet!");
}
@@ -271,7 +305,7 @@
void EmitSymbolTable();
void EmitSectionTableStringTable();
- void EmitSectionTable();
+ void OutputSectionsAndSectionTable();
};
}
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