ELF: add header files, begin merging common code, drop .comment

Add something approaching real ELF header files.

Begin merging the common ELF code, beginning with the section name
detection.

Drop automatic generation of .comment section, and in particular the
treatment of .common as a special section (if we decide generating
.comment is still a good idea, we should just do it as a macro.)

Augment the list of known sections, and make it table-driven.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 31 insertions, 174 deletions

diff --git a/output/outelf64.c b/output/outelf64.c
index 484c4ba..4b2325f 100644
--- a/output/outelf64.c
+++ b/output/outelf64.c
@@ -23,115 +23,13 @@
 #include "outlib.h"
 #include "rbtree.h"
 
-/* Definitions in lieu of elf.h */
-#define SHT_NULL 0			/* Inactive section header */
-#define SHT_PROGBITS 1			/* Program defined content */
-#define SHT_RELA	  4		/* Relocation entries with addends */
-#define SHT_NOBITS 8			/* Section requires no space in file */
-#define SHF_WRITE	     (1 << 0)	/* Writable */
-#define SHF_ALLOC	     (1 << 1)	/* Occupies memory during execution */
-#define SHF_EXECINSTR	     (1 << 2)	/* Executable */
-#define SHF_TLS		     (1 << 10)	/* Section hold thread-local data.  */
-#define SHN_ABS		0xfff1		/* Associated symbol is absolute */
-#define SHN_COMMON	0xfff2		/* Associated symbol is common */
-#define R_X86_64_NONE		0	/* No reloc */
-#define R_X86_64_64		1	/* Direct 64 bit  */
-#define R_X86_64_PC32		2	/* PC relative 32 bit signed */
-#define R_X86_64_GOT32		3	/* 32 bit GOT entry */
-#define R_X86_64_PLT32		4	/* 32 bit PLT address */
-#define R_X86_64_COPY		5	/* Copy symbol at runtime */
-#define R_X86_64_GLOB_DAT	6	/* Create GOT entry */
-#define R_X86_64_JUMP_SLOT	7	/* Create PLT entry */
-#define R_X86_64_RELATIVE	8	/* Adjust by program base */
-#define R_X86_64_GOTPCREL	9	/* 32 bit signed PC relative
-					   offset to GOT */
-#define R_X86_64_32		10	/* Direct 32 bit zero extended */
-#define R_X86_64_32S		11	/* Direct 32 bit sign extended */
-#define R_X86_64_16		12	/* Direct 16 bit zero extended */
-#define R_X86_64_PC16		13	/* 16 bit sign extended pc relative */
-#define R_X86_64_8		14	/* Direct 8 bit sign extended  */
-#define R_X86_64_PC8		15	/* 8 bit sign extended pc relative */
-#define R_X86_64_DTPMOD64	16	/* ID of module containing symbol */
-#define R_X86_64_DTPOFF64	17	/* Offset in module's TLS block */
-#define R_X86_64_TPOFF64	18	/* Offset in initial TLS block */
-#define R_X86_64_TLSGD		19	/* 32 bit signed PC relative offset
-					   to two GOT entries for GD symbol */
-#define R_X86_64_TLSLD		20	/* 32 bit signed PC relative offset
-					   to two GOT entries for LD symbol */
-#define R_X86_64_DTPOFF32	21	/* Offset in TLS block */
-#define R_X86_64_GOTTPOFF	22	/* 32 bit signed PC relative offset
-					   to GOT entry for IE symbol */
-#define R_X86_64_TPOFF32	23	/* Offset in initial TLS block */
-#define R_X86_64_PC64		24 	/* word64 S + A - P */
-#define R_X86_64_GOTOFF64	25 	/* word64 S + A - GOT */
-#define R_X86_64_GOTPC32	26 	/* word32 GOT + A - P */
-#define R_X86_64_GOT64		27 	/* word64 G + A */
-#define R_X86_64_GOTPCREL64	28 	/* word64 G + GOT - P + A */
-#define R_X86_64_GOTPC64	29 	/* word64 GOT - P + A */
-#define R_X86_64_GOTPLT64	30 	/* word64 G + A */
-#define R_X86_64_PLTOFF64	31 	/* word64 L - GOT + A */
-#define R_X86_64_SIZE32		32 	/* word32 Z + A */
-#define R_X86_64_SIZE64		33 	/* word64 Z + A */
-#define R_X86_64_GOTPC32_TLSDESC 34 	/* word32 */
-#define R_X86_64_TLSDESC_CALL	35 	/* none */
-#define R_X86_64_TLSDESC	36 	/* word64×2 */
-#define ET_REL		1		/* Relocatable file */
-#define EM_X86_64	62		/* AMD x86-64 architecture */
-#define STT_NOTYPE	0		/* Symbol type is unspecified */
-#define STT_OBJECT	1		/* Symbol is a data object */
-#define STT_FUNC	2		/* Symbol is a code object */
-#define STT_SECTION	3		/* Symbol associated with a section */
-#define STT_FILE	4		/* Symbol's name is file name */
-#define STT_COMMON	5		/* Symbol is a common data object */
-#define STT_TLS		6		/* Symbol is thread-local data object*/
-#define	STT_NUM		7		/* Number of defined types.  */
-
-/* Definitions in lieu of dwarf.h */
-#define    DW_TAG_compile_unit   0x11
-#define    DW_TAG_subprogram   0x2e
-#define    DW_AT_name   0x03
-#define    DW_AT_stmt_list   0x10
-#define    DW_AT_low_pc   0x11
-#define    DW_AT_high_pc   0x12
-#define    DW_AT_language  0x13
-#define    DW_AT_producer   0x25
-#define    DW_AT_frame_base   0x40
-#define    DW_FORM_addr   0x01
-#define    DW_FORM_data2   0x05
-#define    DW_FORM_data4   0x06
-#define    DW_FORM_string   0x08
-#define    DW_LNS_extended_op  0
-#define    DW_LNS_advance_pc   2
-#define    DW_LNS_advance_line   3
-#define    DW_LNS_set_file   4
-#define    DW_LNE_end_sequence   1
-#define    DW_LNE_set_address   2
-#define    DW_LNE_define_file   3
-#define    DW_LANG_Mips_Assembler  0x8001
-
-#define SOC(ln,aa) ln - line_base + (line_range * aa) + opcode_base
-
-typedef uint32_t Elf64_Word;
-typedef uint64_t Elf64_Xword;
-typedef uint64_t Elf64_Addr;
-typedef uint64_t Elf64_Off;
-typedef struct
-{
-  Elf64_Word	sh_name;	/* Section name (string tbl index) */
-  Elf64_Word	sh_type;	/* Section type */
-  Elf64_Xword	sh_flags;	/* Section flags */
-  Elf64_Addr	sh_addr;	/* Section virtual addr at execution */
-  Elf64_Off	sh_offset;	/* Section file offset */
-  Elf64_Xword	sh_size;	/* Section size in bytes */
-  Elf64_Word	sh_link;	/* Link to another section */
-  Elf64_Word	sh_info;	/* Additional section information */
-  Elf64_Xword	sh_addralign;	/* Section alignment */
-  Elf64_Xword	sh_entsize;	/* Entry size if section holds table */
-} Elf64_Shdr;
-
+#include "elf64.h"
+#include "dwarf.h"
+#include "outelf.h"
 
 #ifdef OF_ELF64
 
+#define SOC(ln,aa) ln - line_base + (line_range * aa) + opcode_base
 
 struct Reloc {
     struct Reloc *next;
@@ -199,22 +97,6 @@ static uint8_t elf_abiver = 0;	/* Current ABI version */
 
 extern struct ofmt of_elf64;
 
-#define SHN_UNDEF 0
-
-#define SYM_GLOBAL 0x10
-
-#define STV_DEFAULT 0
-#define STV_INTERNAL 1
-#define STV_HIDDEN 2
-#define STV_PROTECTED 3
-
-#define GLOBAL_TEMP_BASE 1048576     /* bigger than any reasonable sym id */
-
-#define SEG_ALIGN 16            /* alignment of sections in file */
-#define SEG_ALIGN_1 (SEG_ALIGN-1)
-
-#define TY_DEBUGSYMLIN 0x40     /* internal call to debug_out */
-
 static struct ELF_SECTDATA {
     void *data;
     int64_t len;
@@ -454,9 +336,9 @@ static int elf_make_section(char *name, int type, int flags, int align)
 static int32_t elf_section_names(char *name, int pass, int *bits)
 {
     char *p;
-    unsigned flags_and, flags_or;
-    uint64_t type, align;
-    int i;
+    uint32_t flags, flags_and, flags_or;
+    uint64_t align;
+    int type, i;
 
     /*
      * Default is 64 bits.
@@ -522,9 +404,9 @@ static int32_t elf_section_names(char *name, int pass, int *bits)
                   " declaration of section `%s'", q, name);
     }
 
-    if (!strcmp(name, ".comment") ||
-        !strcmp(name, ".shstrtab") ||
-        !strcmp(name, ".symtab") || !strcmp(name, ".strtab")) {
+    if (!strcmp(name, ".shstrtab") ||
+        !strcmp(name, ".symtab") ||
+        !strcmp(name, ".strtab")) {
         error(ERR_NONFATAL, "attempt to redefine reserved section"
               "name `%s'", name);
         return NO_SEG;
@@ -534,31 +416,19 @@ static int32_t elf_section_names(char *name, int pass, int *bits)
         if (!strcmp(name, sects[i]->name))
             break;
     if (i == nsects) {
-        if (!strcmp(name, ".text"))
-            i = elf_make_section(name, SHT_PROGBITS,
-                                 SHF_ALLOC | SHF_EXECINSTR, 16);
-        else if (!strcmp(name, ".rodata"))
-            i = elf_make_section(name, SHT_PROGBITS, SHF_ALLOC, 4);
-        else if (!strcmp(name, ".data"))
-            i = elf_make_section(name, SHT_PROGBITS,
-                                 SHF_ALLOC | SHF_WRITE, 4);
-        else if (!strcmp(name, ".bss"))
-            i = elf_make_section(name, SHT_NOBITS,
-                                 SHF_ALLOC | SHF_WRITE, 4);
-        else if (!strcmp(name, ".tdata"))
-            i = elf_make_section(name, SHT_PROGBITS,
-                                 SHF_ALLOC | SHF_WRITE | SHF_TLS, 4);
-        else if (!strcmp(name, ".tbss"))
-            i = elf_make_section(name, SHT_NOBITS,
-                                 SHF_ALLOC | SHF_WRITE | SHF_TLS, 4);
-        else
-            i = elf_make_section(name, SHT_PROGBITS, SHF_ALLOC, 1);
-        if (type)
-            sects[i]->type = type;
-        if (align)
-            sects[i]->align = align;
-        sects[i]->flags &= ~flags_and;
-        sects[i]->flags |= flags_or;
+	const struct elf_known_section *ks = elf_known_sections;
+
+	while (ks->name) {
+	    if (!strcmp(name, ks->name))
+		break;
+	    ks++;
+	}
+
+	type = type ? type : ks->type;
+	align = align ? align : ks->align;
+	flags = (ks->flags & ~flags_and) | flags_or;
+
+	i = elf_make_section(name, type, flags, align);
     } else if (pass == 1) {
           if ((type && sects[i]->type != type)
              || (align && sects[i]->align != align)
@@ -1155,8 +1025,6 @@ static void elf_write(void)
     int align;
     int scount;
     char *p;
-    int commlen;
-    char comment[64];
     int i;
 
     struct SAA *symtab;
@@ -1164,18 +1032,16 @@ static void elf_write(void)
 
     /*
      * Work out how many sections we will have. We have SHN_UNDEF,
-     * then the flexible user sections, then the four fixed
-     * sections `.comment', `.shstrtab', `.symtab' and `.strtab',
-     * then optionally relocation sections for the user sections.
+     * then the flexible user sections, then the fixed sections
+     * `.shstrtab', `.symtab' and `.strtab', then optionally
+     * relocation sections for the user sections.
      */
+    nsections = 4;
     if (of_elf64.current_dfmt == &df_stabs)
-        nsections = 8;
+        nsections += 3;
     else if (of_elf64.current_dfmt == &df_dwarf)
-        nsections = 15;
-    else
-        nsections = 5;          /* SHN_UNDEF and the fixed ones */
+        nsections += 10;
 
-    add_sectname("", ".comment");
     add_sectname("", ".shstrtab");
     add_sectname("", ".symtab");
     add_sectname("", ".strtab");
@@ -1215,12 +1081,6 @@ static void elf_write(void)
     }
 
     /*
-     * Do the comment.
-     */
-    *comment = '\0';
-    commlen = 2 + snprintf(comment+1, sizeof comment-1, "%s", nasm_comment);
-
-    /*
      * Output the ELF header.
      */
     fwrite("\177ELF\2\1\1", 7, 1, elffp);
@@ -1272,9 +1132,6 @@ static void elf_write(void)
         p += strlen(p) + 1;
         scount++;               /* ditto */
     }
-    elf_section_header(p - shstrtab, 1, 0, comment, false, (int32_t)commlen, 0, 0, 1, 0);  /* .comment */
-    scount++;                   /* ditto */
-    p += strlen(p) + 1;
     elf_section_header(p - shstrtab, 3, 0, shstrtab, false, (int32_t)shstrtablen, 0, 0, 1, 0);     /* .shstrtab */
     scount++;                   /* ditto */
     p += strlen(p) + 1;
@@ -1623,7 +1480,7 @@ static int elf_set_info(enum geninfo type, char **val)
     return 0;
 }
 static struct dfmt df_dwarf = {
-    "ELF64 (X86_64) dwarf debug format for Linux",
+    "ELF64 (x86-64) dwarf debug format for Linux/Unix",
     "dwarf",
     debug64_init,
     dwarf64_linenum,
@@ -1634,7 +1491,7 @@ static struct dfmt df_dwarf = {
     dwarf64_cleanup
 };
 static struct dfmt df_stabs = {
-    "ELF64 (X86_64) stabs debug format for Linux",
+    "ELF64 (x86-64) stabs debug format for Linux/Unix",
     "stabs",
     debug64_init,
     stabs64_linenum,