Allow any build-id length between 4 and 20 bytes inclusive

emaste · emaste · commit 81955f8048b3 · 2016-03-14T14:06:00.000Z
Build-id support is being added to lld and by default it may produce a 64-bit build-id. Prior to this change lldb would reject such a build-id. However, it then falls back to a 4-byte crc32, which is a poorer quality identifier. Differential Revision: http://reviews.llvm.org/D18096 llvm-svn: 263432
diff --git a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -1410,8 +1410,9 @@ ObjectFileELF::RefineModuleDetailsFromNote (lldb_private::DataExtractor &data, l
                     // Only bother processing this if we don't already have the uuid set.
                     if (!uuid.IsValid())
                     {
-                        // 16 bytes is UUID|MD5, 20 bytes is SHA1
-                        if ((note.n_descsz == 16 || note.n_descsz == 20))
+                        // 16 bytes is UUID|MD5, 20 bytes is SHA1. Other linkers may produce a build-id of a different
+                        // length. Accept it as long as it's at least 4 bytes as it will be better than our own crc32.
+                        if (note.n_descsz >= 4 && note.n_descsz <= 20)
                         {
                             uint8_t uuidbuf[20];
                             if (data.GetU8 (&offset, &uuidbuf, note.n_descsz) == nullptr)

Original file line number	Diff line number	Diff line change
`@@ -1410,8 +1410,9 @@ ObjectFileELF::RefineModuleDetailsFromNote (lldb_private::DataExtractor &data, l`
`1410`	`1410`	`// Only bother processing this if we don't already have the uuid set.`
`1411`	`1411`	`if (!uuid.IsValid())`
`1412`	`1412`	`{`
`1413`		`- // 16 bytes is UUID\|MD5, 20 bytes is SHA1`
`1414`		`- if ((note.n_descsz == 16 \|\| note.n_descsz == 20))`
	`1413`	`+ // 16 bytes is UUID\|MD5, 20 bytes is SHA1. Other linkers may produce a build-id of a different`
	`1414`	`+ // length. Accept it as long as it's at least 4 bytes as it will be better than our own crc32.`
	`1415`	`+ if (note.n_descsz >= 4 && note.n_descsz <= 20)`
`1415`	`1416`	`{`
`1416`	`1417`	`uint8_t uuidbuf[20];`
`1417`	`1418`	`if (data.GetU8 (&offset, &uuidbuf, note.n_descsz) == nullptr)`