Fix clang 15 int to pointer conversion errors

Since version 15, clang issues error for implicit conversion of
integer to pointer. Several tools are broken. This patch add explicit
pointer cast where needed.

Fixes the following errors:
/virtual/main.c:37:18: error: incompatible integer to pointer conversion initializing 'struct request *' with an expression of type 'unsigned long' [-Wint-conversion]
 struct request *req = ctx->di;
                 ^     ~~~~~~~
/virtual/main.c:49:18: error: incompatible integer to pointer conversion initializing 'struct request *' with an expression of type 'unsigned long' [-Wint-conversion]
 struct request *req = ctx->di;
                 ^     ~~~~~~~
2 errors generated.

/virtual/main.c:73:19: error: incompatible integer to pointer conversion initializing 'struct pt_regs *' with an expression of type 'unsigned long' [-Wint-conversion]
 struct pt_regs * __ctx = ctx->di;
                  ^       ~~~~~~~
/virtual/main.c:100:240: error: incompatible integer to pointer conversion passing 'u64' (aka 'unsigned long long') to parameter of type 'const void *' [-Wint-conversion]
    data.ppid = ({ typeof(pid_t) _val; __builtin_memset(&_val, 0, sizeof(_val)); bpf_probe_read(&_val, sizeof(_val), (u64)&({ typeof(struct task_struct *) _val; __builtin_memset(&_val, 0, sizeof(_val)); bpf_probe_read(&_val, sizeof(_val), (u64)&task->real_parent); _val; })->tgid); _val; });
                                                                                                                                                                                                                                               ^~~~~~~~~~~~~~~~~~~~~~~
/virtual/main.c:100:118: error: incompatible integer to pointer conversion passing 'u64' (aka 'unsigned long long') to parameter of type 'const void *' [-Wint-conversion]
    data.ppid = ({ typeof(pid_t) _val; __builtin_memset(&_val, 0, sizeof(_val)); bpf_probe_read(&_val, sizeof(_val), (u64)&({ typeof(struct task_struct *) _val; __builtin_memset(&_val, 0, sizeof(_val)); bpf_probe_read(&_val, sizeof(_val), (u64)&task->real_parent); _val; })->tgid); _val; });
                                                                                                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Jerome Marchand <[email protected]>

src/cc/frontends/clang/b_frontend_action.cc

@@ -521,9 +521,9 @@ bool ProbeVisitor::VisitUnaryOperator(UnaryOperator *E) {
  string pre, post;
  pre = "({ typeof(" + E->getType().getAsString() + ") _val; __builtin_memset(&_val, 0, sizeof(_val));";
  if (cannot_fall_back_safely)
- pre += " bpf_probe_read_kernel(&_val, sizeof(_val), (u64)";
+ pre += " bpf_probe_read_kernel(&_val, sizeof(_val), (void *)";
  else
- pre += " bpf_probe_read(&_val, sizeof(_val), (u64)";
+ pre += " bpf_probe_read(&_val, sizeof(_val), (void *)";
  post = "); _val; })";
  rewriter_.ReplaceText(expansionLoc(E->getOperatorLoc()), 1, pre);
  rewriter_.InsertTextAfterToken(expansionLoc(GET_ENDLOC(sub)), post);
@@ -585,9 +585,9 @@ bool ProbeVisitor::VisitMemberExpr(MemberExpr *E) {
  string pre, post;
  pre = "({ typeof(" + E->getType().getAsString() + ") _val; __builtin_memset(&_val, 0, sizeof(_val));";
  if (cannot_fall_back_safely)
- pre += " bpf_probe_read_kernel(&_val, sizeof(_val), (u64)&";
+ pre += " bpf_probe_read_kernel(&_val, sizeof(_val), (void *)&";
  else
- pre += " bpf_probe_read(&_val, sizeof(_val), (u64)&";
+ pre += " bpf_probe_read(&_val, sizeof(_val), (void *)&";
  post = rhs + "); _val; })";
  rewriter_.InsertText(expansionLoc(GET_BEGINLOC(E)), pre);
  rewriter_.ReplaceText(expansionRange(SourceRange(member, GET_ENDLOC(E))), post);
@@ -639,9 +639,9 @@ bool ProbeVisitor::VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
 
  pre = "({ typeof(" + E->getType().getAsString() + ") _val; __builtin_memset(&_val, 0, sizeof(_val));";
  if (cannot_fall_back_safely)
- pre += " bpf_probe_read_kernel(&_val, sizeof(_val), (u64)((";
+ pre += " bpf_probe_read_kernel(&_val, sizeof(_val), (void *)((";
  else
- pre += " bpf_probe_read(&_val, sizeof(_val), (u64)((";
+ pre += " bpf_probe_read(&_val, sizeof(_val), (void *)((";
  if (isMemberDereference(base)) {
  pre += "&";
  // If the base of the array subscript is a member dereference, we'll rewrite
@@ -751,8 +751,8 @@ void BTypeVisitor::genParamDirectAssign(FunctionDecl *D, string& preamble,
  arg->addAttr(UnavailableAttr::CreateImplicit(C, "ptregs"));
  size_t d = idx - 1;
  const char *reg = calling_conv_regs[d];
- preamble += " " + text + " = " + fn_args_[0]->getName().str() + "->" +
- string(reg) + ";";
+ preamble += " " + text + " = (" + arg->getType().getAsString() + ")" +
+ fn_args_[0]->getName().str() + "->" + string(reg) + ";";
  }
  }
 }
@@ -766,7 +766,7 @@ void BTypeVisitor::genParamIndirectAssign(FunctionDecl *D, string& preamble,
 
  if (idx == 0) {
  new_ctx = "__" + arg->getName().str();
- preamble += " struct pt_regs * " + new_ctx + " = " +
+ preamble += " struct pt_regs * " + new_ctx + " = (void *)" +
  arg->getName().str() + "->" +
  string(calling_conv_regs[0]) + ";";
  } else {