Add x86_64-linux-gnu emulator

I wanted a tiny scriptable meltdown proof way to run userspace programs
and visualize how program execution impacts memory. It helps to explain
how things like Actually Portable Executable works. It can show you how
the GCC generated code is going about manipulating matrices and more. I
didn't feel fully comfortable with Qemu and Bochs because I'm not smart
enough to understand them. I wanted something like gVisor but with much
stronger levels of assurances. I wanted a single binary that'll run, on
all major operating systems with an embedded GPL barrier ZIP filesystem
that is tiny enough to transpile to JavaScript and run in browsers too.

https://justine.storage.googleapis.com/emulator625.mp4

tool/decode/lib/elfidnames.c

@@ -17,6 +17,7 @@
 │ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
 │ 02110-1301 USA                                                               │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/elf/def.h"
 #include "libc/elf/elf.h"
 #include "tool/decode/lib/elfidnames.h"
 

tool/decode/lib/flagger.c

@@ -17,17 +17,12 @@
 │ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
 │ 02110-1301 USA                                                               │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/alg/arraylist.h"
+#include "libc/alg/arraylist2.h"
 #include "libc/fmt/fmt.h"
 #include "libc/mem/mem.h"
 #include "libc/str/str.h"
 #include "tool/decode/lib/flagger.h"
 
-struct FlagNameBuf {
-  size_t i, n;
-  char *p;
-};
-
 /**
  * Formats numeric flags integer as symbolic code.
  *
@@ -35,28 +30,32 @@ struct FlagNameBuf {
  * @param id is the flags
  * @return NUL-terminated string that needs free()
  */
-nodiscard char *recreateflags(const struct IdName *names, unsigned long id) {
-  struct FlagNameBuf buf = {};
-  char extrabuf[20];
+nodiscard char *RecreateFlags(const struct IdName *names, unsigned long id) {
   bool first;
+  size_t bufi, bufn;
+  char *bufp, extrabuf[20];
+  bufi = 0;
+  bufn = 0;
+  bufp = NULL;
   first = true;
   for (; names->name; names++) {
     if ((id == 0 && names->id == 0) ||
         (id != 0 && names->id != 0 && (id & names->id) == names->id)) {
       id &= ~names->id;
       if (!first) {
-        append(&buf, "|");
+        APPEND(&bufp, &bufi, &bufn, "|");
       } else {
         first = false;
       }
-      concat(&buf, names->name, strlen(names->name));
+      CONCAT(&bufp, &bufi, &bufn, names->name, strlen(names->name));
     }
   }
   if (id) {
-    if (buf.i) append(&buf, "|");
-    concat(&buf, extrabuf, snprintf(extrabuf, sizeof(extrabuf), "%#x", id));
-  } else if (!buf.i) {
-    append(&buf, "0");
+    if (bufi) APPEND(&bufp, &bufi, &bufn, "|");
+    CONCAT(&bufp, &bufi, &bufn, extrabuf,
+           snprintf(extrabuf, sizeof(extrabuf), "%#x", id));
+  } else if (!bufi) {
+    APPEND(&bufp, &bufi, &bufn, "0");
   }
-  return buf.p;
+  return bufp;
 }

tool/decode/lib/flagger.h

@@ -4,7 +4,7 @@
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
 
-char *recreateflags(const struct IdName *, unsigned long) nodiscard;
+char *RecreateFlags(const struct IdName *, unsigned long) nodiscard;
 
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */

tool/decode/lib/pollnames.S

@@ -49,7 +49,7 @@ kPollNamesRo:
 	.previous
 
 /	Mapping of poll() flags to their string names.
-/	@see	recreateflags()
+/	@see	RecreateFlags()
 	.initbss 301,_init_kPollNames
 kPollNames:
 	.rept	.Lrows

tool/decode/lib/xederrors.c

@@ -20,7 +20,7 @@
 #include "third_party/xed/x86.h"
 #include "tool/decode/lib/idname.h"
 
-const struct IdName kXedErrorNames[] = {
+const struct IdName kXedErrorIdNames[] = {
     {XED_ERROR_NONE, "NONE"},
     {XED_ERROR_BUFFER_TOO_SHORT, "BUFFER_TOO_SHORT"},
     {XED_ERROR_GENERAL_ERROR, "GENERAL_ERROR"},

tool/decode/lib/xederrors.h

@@ -4,7 +4,7 @@
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
 
-extern const struct IdName kXedErrorNames[];
+extern const struct IdName kXedErrorIdNames[];
 
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */