From c17a12ac030c5d9c812e611f8132570af0e795af Mon Sep 17 00:00:00 2001
From: Yonghong Song <yhs@fb.com>
Date: Sat, 13 Aug 2022 17:50:07 -0700
Subject: [PATCH 1/2] Fix bpf_pseudo_fd() type conversion error

With llvm15 and llvm16, the following command line
  sudo ./trace.py 'smp_call_function_single "%K", arg1'
will cause error:
  /virtual/main.c:60:36: error: incompatible integer to pointer conversion passing 'u64'
    (aka 'unsigned long long') to parameter of type 'void *' [-Wint-conversion]
        bpf_perf_event_output(ctx, bpf_pseudo_fd(1, -1), CUR_CPU_IDENTIFIER, &__data, sizeof(__data));
                                   ^~~~~~~~~~~~~~~~~~~~
  1 error generated.
  Failed to compile BPF module <text>

In helpers.h, we have
  u64 bpf_pseudo_fd(u64, u64) asm("llvm.bpf.pseudo");
Apparently, <= llvm14 can tolerate u64 -> 'void *' conversion, but
llvm15 by default will cause an error.

Let us explicitly convert bpf_pseudo_fd to 'void *' to avoid
such errors.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 src/cc/frontends/clang/b_frontend_action.cc | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/cc/frontends/clang/b_frontend_action.cc b/src/cc/frontends/clang/b_frontend_action.cc
index a4e05b16..dbeba3e4 100644
--- a/src/cc/frontends/clang/b_frontend_action.cc
+++ b/src/cc/frontends/clang/b_frontend_action.cc
@@ -957,7 +957,7 @@ bool BTypeVisitor::VisitCallExpr(CallExpr *Call) {
           string arg0 = rewriter_.getRewrittenText(expansionRange(Call->getArg(0)->getSourceRange()));
           string args_other = rewriter_.getRewrittenText(expansionRange(SourceRange(GET_BEGINLOC(Call->getArg(1)),
                                                            GET_ENDLOC(Call->getArg(2)))));
-          txt = "bpf_perf_event_output(" + arg0 + ", bpf_pseudo_fd(1, " + fd + ")";
+          txt = "bpf_perf_event_output(" + arg0 + ", (void *)bpf_pseudo_fd(1, " + fd + ")";
           txt += ", CUR_CPU_IDENTIFIER, " + args_other + ")";
 
           // e.g.
@@ -986,7 +986,7 @@ bool BTypeVisitor::VisitCallExpr(CallExpr *Call) {
           string meta_len = rewriter_.getRewrittenText(expansionRange(Call->getArg(3)->getSourceRange()));
           txt = "bpf_perf_event_output(" +
             skb + ", " +
-            "bpf_pseudo_fd(1, " + fd + "), " +
+            "(void *)bpf_pseudo_fd(1, " + fd + "), " +
             "((__u64)" + skb_len + " << 32) | BPF_F_CURRENT_CPU, " +
             meta + ", " +
             meta_len + ");";
@@ -1006,12 +1006,12 @@ bool BTypeVisitor::VisitCallExpr(CallExpr *Call) {
           string keyp = rewriter_.getRewrittenText(expansionRange(Call->getArg(1)->getSourceRange()));
           string flag = rewriter_.getRewrittenText(expansionRange(Call->getArg(2)->getSourceRange()));
           txt = "bpf_" + string(memb_name) + "(" + ctx + ", " +
-            "bpf_pseudo_fd(1, " + fd + "), " + keyp + ", " + flag + ");";
+            "(void *)bpf_pseudo_fd(1, " + fd + "), " + keyp + ", " + flag + ");";
         } else if (memb_name == "ringbuf_output") {
           string name = string(Ref->getDecl()->getName());
           string args = rewriter_.getRewrittenText(expansionRange(SourceRange(GET_BEGINLOC(Call->getArg(0)),
                                                            GET_ENDLOC(Call->getArg(2)))));
-          txt = "bpf_ringbuf_output(bpf_pseudo_fd(1, " + fd + ")";
+          txt = "bpf_ringbuf_output((void *)bpf_pseudo_fd(1, " + fd + ")";
           txt += ", " + args + ")";
 
           // e.g.
@@ -1033,7 +1033,7 @@ bool BTypeVisitor::VisitCallExpr(CallExpr *Call) {
         } else if (memb_name == "ringbuf_reserve") {
           string name = string(Ref->getDecl()->getName());
           string arg0 = rewriter_.getRewrittenText(expansionRange(Call->getArg(0)->getSourceRange()));
-          txt = "bpf_ringbuf_reserve(bpf_pseudo_fd(1, " + fd + ")";
+          txt = "bpf_ringbuf_reserve((void *)bpf_pseudo_fd(1, " + fd + ")";
           txt += ", " + arg0 + ", 0)"; // Flags in reserve are meaningless
         } else if (memb_name == "ringbuf_discard") {
           string name = string(Ref->getDecl()->getName());
-- 
2.38.1