[PATCH v4 3/4] gas: bpf: test `gotol' in a compound conditional

[Vineet Gupta]

The PR gas/34558 coverage added with the fix exercises only the standalone
`gotol'.  That case can also be fixed by moving BPF_INSN_JAL above
BPF_INSN_JAR in bpf_opcodes[], so that `gotol%w%d32' is tried before
`goto%w%d16'.  The compound conditional jumps embed the same `goto%w%d16'
and have no `gotol' counterpart to reorder ahead of them, so they stay
broken under that approach:

  if r1 > r2 gotol +1

assembles silently to JGT with a R_BPF_GNU_64_16 relocation against an
undefined symbol `l'.  Conditional jumps only have the 16-bit `off' field,
so there is no `gotol' form of them.

Add a test for the compound forms, so the reordering alternative does not
look equivalent to %t.  Verified that it fails when %t is replaced by the
reordering: no diagnostic, and each of its three lines silently encoded as
a conditional jump with a relocation against `l'.

gas/
	* testsuite/gas/bpf/jump-gotol-cond-pseudoc.s: New test.
	* testsuite/gas/bpf/jump-gotol-cond-pseudoc.d: New test.
	* testsuite/gas/bpf/jump-gotol-cond-pseudoc.l: New test.
	* testsuite/gas/bpf/bpf.exp: Run it.

Signed-off-by: Vineet Gupta <vineet.gupta@linux.dev>
---
 gas/testsuite/gas/bpf/bpf.exp                   |  1 +
 gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.d |  4 ++++
 gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.l |  9 +++++++++
 gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.s | 11 +++++++++++
 4 files changed, 25 insertions(+)
 create mode 100644 gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.d
 create mode 100644 gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.l
 create mode 100644 gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.s

diff --git a/gas/testsuite/gas/bpf/bpf.exp b/gas/testsuite/gas/bpf/bpf.exp
index ff52481cda49..9884b36678c2 100644
--- a/gas/testsuite/gas/bpf/bpf.exp
+++ b/gas/testsuite/gas/bpf/bpf.exp
@@ -39,6 +39,7 @@ if {[istarget bpf*-*-*]} {
     run_dump_test jump32
     run_dump_test jump32-pseudoc
     run_dump_test jump-gotol-signed-pseudoc
+    run_dump_test jump-gotol-cond-pseudoc
     run_dump_test atomic-v1
     run_dump_test atomic
     run_dump_test atomic-pseudoc
diff --git a/gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.d b/gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.d
new file mode 100644
index 000000000000..f33ab7fcb35c
--- /dev/null
+++ b/gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.d
@@ -0,0 +1,4 @@
+#as: -EL -mdialect=pseudoc
+#source: jump-gotol-cond-pseudoc.s
+#error_output: jump-gotol-cond-pseudoc.l
+#name: eBPF gotol in a compound conditional, pseudoc syntax
diff --git a/gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.l b/gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.l
new file mode 100644
index 000000000000..a4408334ce5a
--- /dev/null
+++ b/gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.l
@@ -0,0 +1,9 @@
+.*: Assembler messages:
+.*:9: Error: unexpected register name `r2' in instruction `if r1>r2'
+.*:9: Error: unrecognized instruction `if r1>r2 gotol\+1'
+.*:9: Error: expected white space, got 'l\+1'
+.*:10: Error: unrecognized instruction `if r1&5 gotol-1'
+.*:10: Error: expected white space, got 'l-1'
+.*:11: Error: unexpected register name `w2' in instruction `if w1==w2'
+.*:11: Error: unrecognized instruction `if w1==w2 gotol\+1'
+.*:11: Error: expected white space, got 'l\+1'
diff --git a/gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.s b/gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.s
new file mode 100644
index 000000000000..14625473a9af
--- /dev/null
+++ b/gas/testsuite/gas/bpf/jump-gotol-cond-pseudoc.s
@@ -0,0 +1,11 @@
+        # PR gas/34558: `gotol' written where a compound conditional jump
+        # expects `goto'.  Conditional jumps only have the 16-bit `off'
+        # field, so there is no `gotol' form of them.  These used to match
+        # the embedded `goto%w%d16' of the conditional templates, with the
+        # trailing `l' parsed as the start of the branch offset expression,
+        # silently assembling to a conditional jump plus a relocation
+        # against an undefined symbol `l'.
+        .text
+        if r1 > r2 gotol +1
+        if r1 & 5 gotol -1
+        if w1 == w2 gotol +1
-- 
2.53.0-Meta