maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

Do not access beyond the end of local symbols. 

This patch resurrects code that was removed in r317007 to not access
beyond allocated memory for a symbol.

Differential Revision: https://reviews.llvm.org/D39458

llvm-svn: 317039
This commit is contained in:
Rui Ueyama 2017-10-31 21:26:42 +00:00
parent 5914ece6aa
commit 9fa2813803
1 changed files with 11 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
lld/COFF/SymbolTable.cpp
View File

@ -106,7 +106,17 @@ void SymbolTable::reportRemainingUndefines() {
// A weak alias may have been resolved, so check for that.
if (Defined *D = Undef->getWeakAlias()) {
memcpy(Sym, D, sizeof(SymbolUnion));
// We want to replace Sym with D. However, we can't just blindly
// copy sizeof(SymbolUnion) bytes from D to Sym because D may be an
// internal symbol, and internal symbols are stored as "unparented"
// Symbols. For that reason we need to check which type of symbol we
// are dealing with and copy the correct number of bytes.
if (isa<DefinedRegular>(D))
memcpy(Sym, D, sizeof(DefinedRegular));
else if (isa<DefinedAbsolute>(D))
memcpy(Sym, D, sizeof(DefinedAbsolute));
else
memcpy(Sym, D, sizeof(SymbolUnion));
continue;
}