Eric Pouech : dbghelp: Silence some FIXMEs.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 0c3d78269f9a463bf43bebdf08db368aef484cca
URL:    https://gitlab.winehq.org/wine/wine/-/commit/0c3d78269f9a463bf43bebdf08db368...

Author: Eric Pouech 
Date:   Wed Oct 19 17:27:43 2022 +0200

dbghelp: Silence some FIXMEs.

In some 32bit modules, MingW/GCC generates in Dwarf debug information,
a cfa address to be computed as:
   deref(register XX + offset)
which is too complicated to be expressed through regular DbgHelp APIs.

So silence the FIXME, and report a 'too complex' error (instead of
'internal').

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52790
Signed-off-by: Eric Pouech

---

dlls/dbghelp/dwarf.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/dlls/dbghelp/dwarf.c b/dlls/dbghelp/dwarf.c
index 8d365ba88f1..4671174d3bb 100644
--- a/dlls/dbghelp/dwarf.c
+++ b/dlls/dbghelp/dwarf.c
@@ -3028,7 +3028,7 @@ static const dwarf2_cuhead_t* get_cuhead_from_func(const struct symt_function* f
     return NULL;
 }

-static BOOL compute_call_frame_cfa(struct module* module, ULONG_PTR ip, struct location* frame);
+static enum location_error compute_call_frame_cfa(struct module* module, ULONG_PTR ip, struct location* frame);

static enum location_error loc_compute_frame(struct process* pcs,
                                              const struct module_format* modfmt,
@@ -3071,7 +3071,8 @@ static enum location_error loc_compute_frame(struct process* pcs,
                 }
                 break;
             case loc_dwarf2_frame_cfa:
-                if (!compute_call_frame_cfa(modfmt->module, ip + ((struct symt_compiland*)func->container)->address, frame)) return loc_err_internal;
+                err = compute_call_frame_cfa(modfmt->module, ip + ((struct symt_compiland*)func->container)->address, frame);
+                if (err < 0) return err;
                 break;
             default:
                 WARN("Unsupported frame kind %d\n", pframe->kind);
@@ -3866,11 +3867,11 @@ BOOL dwarf2_virtual_unwind(struct cpu_stack_walk *csw, ULONG_PTR ip,
     return TRUE;
 }

-static BOOL compute_call_frame_cfa(struct module* module, ULONG_PTR ip, struct location* frame)
+static enum location_error compute_call_frame_cfa(struct module* module, ULONG_PTR ip, struct location* frame)
 {
     struct frame_info info;

-    if (!dwarf2_fetch_frame_info(module, module->cpu, ip, &info)) return FALSE;
+    if (!dwarf2_fetch_frame_info(module, module->cpu, ip, &info)) return loc_err_internal;

/* beginning of function, or no available dwarf information ? */
     if (ip == info.ip || info.state.rules[info.retaddr_reg] == RULE_UNSET)
@@ -3888,11 +3889,15 @@ static BOOL compute_call_frame_cfa(struct module* module, ULONG_PTR ip, struct l
         switch (info.state.cfa_rule)
         {
         case RULE_EXPRESSION:
-            FIXME("Too complex expression for frame_CFA resolution (RULE_EXPRESSION)\n");
-            return FALSE;
+            WARN("Too complex expression for frame_CFA resolution (RULE_EXPRESSION)\n");
+            return loc_err_too_complex;
         case RULE_VAL_EXPRESSION:
-            FIXME("Too complex expression for frame_CFA resolution (RULE_VAL_EXPRESSION)\n");
-            return FALSE;
+            /* unfortunately, we've seen at least construct like:
+             *     cfa := 'breg_x + offset; deref'
+             * which is an indirection too much for the DbgHelp API.
+             */
+            WARN("Too complex expression for frame_CFA resolution (RULE_VAL_EXPRESSION)\n");
+            return loc_err_too_complex;
         default:
             frame->kind = loc_regrel;
             frame->reg = module->cpu->map_dwarf_register(info.state.cfa_reg, module, TRUE);
@@ -3900,7 +3905,7 @@ static BOOL compute_call_frame_cfa(struct module* module, ULONG_PTR ip, struct l
             break;
         }
     }
-    return TRUE;
+    return 0;
 }

static void dwarf2_location_compute(struct process* pcs,