Eric Pouech : dbghelp/dwarf: Workaround functions with multiple range of addresses.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: acfcd84a05bfbb2ea5c2ff0b235508cc2f452859
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=acfcd84a05bfbb2ea5c2ff0b2...

Author: Eric Pouech <eric.pouech(a)gmail.com>
Date:   Wed Nov 10 16:44:02 2021 +0100

dbghelp/dwarf: Workaround functions with multiple range of addresses.

gcc can emit functions with code spread across non contiguous code areas.
We used to register those functions with an address range enclosing all ranges
(meaning that all addresses not actually belonging to the function but
lying in that address range could be returned by dbghelp as belonging
to the function).

Work around this by registering the function with only the first range
of addresses (this will avoid the errors described above), but will
fail to mark the other address ranges as part of the function.

dbghelp doesn't seem to have explicit support of those cases, even if
pdb/codeview also support functions with multi range of addresses
(see S_SEPCODE).

Signed-off-by: Eric Pouech <eric.pouech(a)gmail.com>
Signed-off-by: Alexandre Julliard <julliard(a)winehq.org>

---

 dlls/dbghelp/dwarf.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/dlls/dbghelp/dwarf.c b/dlls/dbghelp/dwarf.c
index 573c56627a7..ef17f7d539f 100644
--- a/dlls/dbghelp/dwarf.c
+++ b/dlls/dbghelp/dwarf.c
@@ -2239,7 +2239,8 @@ static void dwarf2_parse_subprogram_block(dwarf2_subprogram_t* subpgm,
 static struct symt* dwarf2_parse_subprogram(dwarf2_debug_info_t* di)
 {
     struct attribute name;
-    ULONG_PTR low_pc, high_pc;
+    struct addr_range* addr_ranges;
+    unsigned num_addr_ranges;
     struct attribute is_decl;
     struct attribute inline_flags;
     struct symt* ret_type;
@@ -2276,7 +2277,7 @@ static struct symt* dwarf2_parse_subprogram(dwarf2_debug_info_t* di)
         /* it's a real declaration, skip it */
         return NULL;
     }
-    if (!dwarf2_read_range(di->unit_ctx, di, &low_pc, &high_pc))
+    if ((addr_ranges = dwarf2_get_ranges(di, &num_addr_ranges)) == NULL)
     {
         WARN("cannot get range for %s\n", debugstr_a(name.u.string));
         return NULL;
@@ -2285,7 +2286,7 @@ static struct symt* dwarf2_parse_subprogram(dwarf2_debug_info_t* di)
      * (not the case for stabs), we just drop Wine's thunks here...
      * Actual thunks will be created in elf_module from the symbol table
      */
-    if (elf_is_in_thunk_area(di->unit_ctx->module_ctx->load_offset + low_pc, di->unit_ctx->module_ctx->thunks) >= 0)
+    if (elf_is_in_thunk_area(di->unit_ctx->module_ctx->load_offset + addr_ranges[0].low, di->unit_ctx->module_ctx->thunks) >= 0)
         return NULL;
     ret_type = dwarf2_lookup_type(di);
 
@@ -2293,8 +2294,11 @@ static struct symt* dwarf2_parse_subprogram(dwarf2_debug_info_t* di)
     sig_type = symt_new_function_signature(di->unit_ctx->module_ctx->module, ret_type, CV_CALL_FAR_C);
     subpgm.top_func = symt_new_function(di->unit_ctx->module_ctx->module, di->unit_ctx->compiland,
                                         dwarf2_get_cpp_name(di, name.u.string),
-                                        di->unit_ctx->module_ctx->load_offset + low_pc, high_pc - low_pc,
-                                        &sig_type->symt);
+                                        addr_ranges[0].low, addr_ranges[0].high - addr_ranges[0].low, &sig_type->symt);
+    if (num_addr_ranges > 1)
+        WARN("Function %s has multiple address ranges, only using the first one\n", name.u.string);
+    free(addr_ranges);
+
     subpgm.current_func = subpgm.top_func;
     di->symt = &subpgm.top_func->symt;
     subpgm.ctx = di->unit_ctx;