Fix warnings

This change fixes Cosmopolitan so it has fewer opinions about compiler
warnings. The whole repository had to be cleaned up to be buildable in
-Werror -Wall mode. This lets us benefit from things like strict const
checking. Some actual bugs might have been caught too.

third_party/chibicc/as.c

@@ -775,7 +775,7 @@ static void Tokenize(struct As *a, int path) {
 
 static int GetSymbol(struct As *a, int name) {
   struct HashEntry *p;
-  unsigned i, j, k, n, m, h, n2;
+  unsigned i, j, k, n, m, h;
   if (!(h = crc32c(0, a->slices.p[name].p, a->slices.p[name].n))) h = 1;
   n = a->symbolindex.n;
   i = 0;
@@ -932,7 +932,6 @@ static int NewBinary(struct As *a, enum ExprKind k, int lhs, int rhs) {
 //         | symbol
 //         | reference
 static int ParsePrimary(struct As *a, int *rest, int i) {
-  int e;
   if (IsInt(a, i)) {
     *rest = i + 1;
     return NewPrimary(a, EX_INT, a->ints.p[a->things.p[i].i]);
@@ -1765,7 +1764,7 @@ static void OnSize(struct As *a, struct Slice s) {
 }
 
 static void OnEqu(struct As *a, struct Slice s) {
-  int i, j;
+  int i;
   i = GetSymbol(a, a->things.p[a->i++].i);
   ConsumeComma(a);
   a->symbols.p[i].offset = GetInt(a);
@@ -1967,15 +1966,17 @@ static int RemoveRexw(int x) {
 
 static int GetRegisterReg(struct As *a) {
   int reg;
-  struct Slice wut;
-  if ((reg = FindRegReg(GetSlice(a))) == -1) InvalidRegister(a);
+  if ((reg = FindRegReg(GetSlice(a))) == -1) {
+    InvalidRegister(a);
+  }
   return reg;
 }
 
 static int GetRegisterRm(struct As *a) {
   int reg;
-  struct Slice wut;
-  if ((reg = FindRegRm(GetSlice(a))) == -1) InvalidRegister(a);
+  if ((reg = FindRegRm(GetSlice(a))) == -1) {
+    InvalidRegister(a);
+  }
   return reg;
 }
 
@@ -1992,7 +1993,7 @@ static int ParseModrm(struct As *a, int *disp) {
                │││││├──────┐├┐├─┐├─┐
   0b00000000000000000000000000000000*/
   struct Slice str;
-  int reg, scale, modrm = 0;
+  int reg, modrm = 0;
   if (!ConsumeSegment(a) && IsRegister(a, a->i)) {
     *disp = 0;
     modrm = GetRegisterRm(a) | ISREG;
@@ -2057,12 +2058,12 @@ static void EmitImm(struct As *a, int reg, int imm) {
 }
 
 static void EmitModrm(struct As *a, int reg, int modrm, int disp) {
-  int relo, mod, rm;
+  int relo, mod;
   void (*emitter)(struct As *, uint128_t);
   reg &= 7;
   reg <<= 3;
   if (modrm & ISREG) {
-    EmitByte(a, 0300 | reg | modrm & 7);
+    EmitByte(a, 0300 | reg | (modrm & 7));
   } else {
     if (modrm & ISRIP) {
       EmitByte(a, 005 | reg);
@@ -2348,7 +2349,7 @@ static dontinline void OpXadd(struct As *a) {
 }
 
 static dontinline int OpF6Impl(struct As *a, struct Slice s, int reg) {
-  int modrm, imm, disp;
+  int modrm, disp;
   modrm = ParseModrm(a, &disp);
   reg |= GetOpSize(a, s, modrm, 1) << 3;
   EmitRexOpModrm(a, 0xF6, reg, modrm, disp, 1);
@@ -2642,7 +2643,6 @@ static void OnPush(struct As *a, struct Slice s) {
 }
 
 static void OnRdpid(struct As *a, struct Slice s) {
-  int modrm, disp;
   EmitVarword(a, 0xf30fc7);
   EmitByte(a, 0370 | GetRegisterReg(a));
 }
@@ -2700,6 +2700,8 @@ static void OnFile(struct As *a, struct Slice s) {
   struct Slice path;
   fileno = GetInt(a);
   path = GetSlice(a);
+  (void)fileno;
+  (void)path;
   // TODO: DWARF
 }
 
@@ -2707,6 +2709,8 @@ static void OnLoc(struct As *a, struct Slice s) {
   int fileno, lineno;
   fileno = GetInt(a);
   lineno = GetInt(a);
+  (void)fileno;
+  (void)lineno;
   // TODO: DWARF
 }
 
@@ -2762,7 +2766,7 @@ static void OnFxch(struct As *a, struct Slice s) {
   int rm;
   rm = !IsSemicolon(a) ? GetRegisterRm(a) : 1;
   EmitByte(a, 0xD9);
-  EmitByte(a, 0310 | rm & 7);
+  EmitByte(a, 0310 | (rm & 7));
 }
 
 static void OnBswap(struct As *a, struct Slice s) {
@@ -2770,7 +2774,7 @@ static void OnBswap(struct As *a, struct Slice s) {
   srm = GetRegisterRm(a);
   EmitRex(a, srm);
   EmitByte(a, 0x0F);
-  EmitByte(a, 0310 | srm & 7);
+  EmitByte(a, 0310 | (srm & 7));
 }
 
 static dontinline void OpFcomImpl(struct As *a, int op) {
@@ -2786,7 +2790,7 @@ static dontinline void OpFcomImpl(struct As *a, int op) {
       }
     }
   }
-  EmitVarword(a, op | rm & 7);
+  EmitVarword(a, op | (rm & 7));
 }
 
 static dontinline void OpFcom(struct As *a, int op) {

third_party/chibicc/asm.c

@@ -670,7 +670,7 @@ static void PopAsmInputs(Asm *a) {
 }
 
 static void StoreAsmOutputs(Asm *a) {
-  int i, z, x0, x1;
+  int i, z;
   for (i = 0; i < a->n; ++i) {
     if (a->ops[i].flow == '=' || a->ops[i].flow == '+') {
       switch (a->ops[i].type) {

third_party/chibicc/chibicc.c

@@ -424,7 +424,7 @@ static bool NeedsShellQuotes(const char *s) {
 
 static bool run_subprocess(char **argv) {
   int rc, ws;
-  size_t i, j, n;
+  size_t i, j;
   if (opt_verbose) {
     for (i = 0; argv[i]; i++) {
       fputc(' ', stderr);

third_party/chibicc/chibicc.h

@@ -180,7 +180,7 @@ struct AsmOperand {
   uint8_t reg;
   uint8_t type;
   char flow;
-  char x87mask;
+  unsigned char x87mask;
   bool isused;
   int regmask;
   int predicate;
@@ -216,10 +216,10 @@ void gen_addr(Node *);
 void gen_asm(Asm *);
 void gen_expr(Node *);
 void pop(char *);
-void popreg(char *);
+void popreg(const char *);
 void print_loc(int64_t, int64_t);
 void push(void);
-void pushreg(char *);
+void pushreg(const char *);
 
 //
 // fpclassify.c

third_party/chibicc/codegen.c

@@ -67,7 +67,6 @@ static void emitlin(char *nextline) {
 
 void println(char *fmt, ...) {
   va_list ap;
-  char *nextline;
   va_start(ap, fmt);
   emitlin(xvasprintf(fmt, ap));
   va_end(ap);
@@ -105,12 +104,12 @@ void pop2(char *a, char *b) {
   DCHECK_GE(depth, 0);
 }
 
-void pushreg(char *arg) {
+void pushreg(const char *arg) {
   println("\tpush\t%%%s", arg);
   depth++;
 }
 
-void popreg(char *arg) {
+void popreg(const char *arg) {
   println("\tpop\t%%%s", arg);
   depth--;
   DCHECK_GE(depth, 0);
@@ -1777,15 +1776,13 @@ void gen_expr(Node *node) {
     gen_expr(node->lhs);
     pop("%rdi");
   }
-  char *ax, *di, *dx;
+  char *ax, *di;
   if (node->lhs->ty->kind == TY_LONG || node->lhs->ty->base) {
     ax = "%rax";
     di = "%rdi";
-    dx = "%rdx";
   } else {
     ax = "%eax";
     di = "%edi";
-    dx = "%edx";
   }
   switch (node->kind) {
     case ND_PMOVMSKB:

third_party/chibicc/dox1.c

@@ -42,7 +42,6 @@ struct DoxWriter {
 };
 
 static void SerializeData(struct Buffer *buf, const void *p, unsigned long n) {
-  struct Slice *s;
   buf->p = realloc(buf->p, buf->n + n);
   memcpy(buf->p + buf->n, p, n);
   buf->n += n;

third_party/chibicc/dox2.c

@@ -153,7 +153,6 @@ static char *DeserializeStr(struct Dox *dox) {
 
 static struct Javadown *DeserializeJavadown(struct Dox *dox) {
   int i;
-  bool present;
   struct Javadown *jd;
   if (DeserializeInt(dox)) {
     jd = FreeLater(dox, calloc(1, sizeof(struct Javadown)));
@@ -273,7 +272,7 @@ static bool AddSet(struct Set *set, char *s) {
 static int CompareDoxIndexEntry(const void *p1, const void *p2, void *arg) {
   struct Dox *dox;
   const char *s1, *s2;
-  struct DoxIndexEntry *a, *b;
+  const struct DoxIndexEntry *a, *b;
   dox = arg, a = p1, b = p2;
   s1 = a->t == kObject ? dox->objects.p[a->i].name : dox->macros.p[a->i].name;
   s2 = b->t == kObject ? dox->objects.p[b->i].name : dox->macros.p[b->i].name;

third_party/chibicc/parse.c

@@ -2436,7 +2436,6 @@ static Node *logor(Token **rest, Token *tok) {
 
 // logand = binor ("&&" binor)*
 static Node *logand(Token **rest, Token *tok) {
-  Token *start = tok;
   Node *node = binor(&tok, tok);
   while (EQUAL(tok, "&&")) {
     Token *start = tok;