[RFC PATCH v3 1/4] plugins/api: expose symbol lookup to plugins

[Mahmoud Mandour <ma.mandourr@gmail.com>]

From: Alex Bennée <alex.bennee@linaro.org>

This is a quality of life helper for plugins so they don't need to
re-implement symbol lookup when dumping an address. The strings are
constant so don't need to be duplicated. One minor tweak is to return
NULL instead of a zero length string to show lookup failed.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210601145824.3849-1-alex.bennee@linaro.org>
Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
---
 include/qemu/qemu-plugin.h | 9 +++++++++
 plugins/api.c              | 6 ++++++
 2 files changed, 15 insertions(+)

diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index 97cdfd7761..dc3496f36c 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -525,6 +525,15 @@ qemu_plugin_register_vcpu_syscall_ret_cb(qemu_plugin_id_t id,
 
 char *qemu_plugin_insn_disas(const struct qemu_plugin_insn *insn);
 
+/**
+ * qemu_plugin_insn_symbol() - best effort symbol lookup
+ * @insn: instruction reference
+ *
+ * Return a static string referring to the symbol. This is dependent
+ * on the binary QEMU is running having provided a symbol table.
+ */
+const char *qemu_plugin_insn_symbol(const struct qemu_plugin_insn *insn);
+
 /**
  * qemu_plugin_vcpu_for_each() - iterate over the existing vCPU
  * @id: plugin ID
diff --git a/plugins/api.c b/plugins/api.c
index 817c9b6b69..332e2c60e2 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -233,6 +233,12 @@ char *qemu_plugin_insn_disas(const struct qemu_plugin_insn *insn)
     return plugin_disas(cpu, insn->vaddr, insn->data->len);
 }
 
+const char *qemu_plugin_insn_symbol(const struct qemu_plugin_insn *insn)
+{
+    const char *sym = lookup_symbol(insn->vaddr);
+    return sym[0] != 0 ? sym : NULL;
+}
+
 /*
  * The memory queries allow the plugin to query information about a
  * memory access.
-- 
2.25.1