We have a function which switches on the type of a symbol record
to return a hardcoded offset into the record that contains the
symbol name. Not all symbols have names to begin with, and for
those records we return -1 for the offset.
Names are used for various things. Importantly for this particular
bug, a hash of the record name is used as a key for certain hash
tables which are serialied into the PDB file. One of these hash
tables is for the global symbol stream, which is basically a
collection of S_PROCREF symbols which contain the name of the
symbol, a module, and an address offset.
However, for S_PROCREF symbols, the function to return the offset
of the name was returning -1: basically it wasn't implemented.
As a result of this, all global symbols were hashing to the same
value, essentially it was as if every single global symbol's name
was the empty string.
This manifests in the VS debugger when you try to call a function
(global or member, doesn't matter) through the immediate window
and the debugger simply reports an error because it can't find the
function. This makes perfect sense, because it is hashing the name
for real, looking in the global symbol hash table, and there is only
1 entry there which corresponds to a symbol whose name is the empty
string.
Fixing this fixes the MSVC debugger in this case.
llvm-svn: 336024
Qualifiers on a pointer or reference type may apply to either the
pointee or the pointer itself. Consider 'const char *' and 'char *
const'. In the first example, the pointee data may not be modified
without casts, and in the second example, the pointer may not be updated
to point to new data.
In the general case, qualifiers are applied to types with LF_MODIFIER
records, which support the usual const and volatile qualifiers as well
as the __unaligned extension qualifier.
However, LF_POINTER records, which are used for pointers, references,
and member pointers, have flags for qualifiers applying to the
*pointer*. In fact, this is the only way to represent the restrict
qualifier, which can only apply to pointers, and cannot qualify regular
data types.
This patch causes LLVM to correctly fold 'const' and 'volatile' pointer
qualifiers into the pointer record, as well as adding support for
'__restrict' qualifiers in the same place.
Based on a patch from Aaron Smith
Differential Revision: https://reviews.llvm.org/D43060
llvm-svn: 326260
Previously we were writing an empty globals stream. Windows
tools interpret this as "private symbols are not present in
this PDB", even when they are, so we need to fix this. Regardless,
without it we don't have information about global variables, so
we need to fix it anyway. This patch does that.
With this patch, the "lm" command in WinDbg correctly reports
that we have private symbols available, but the "dv" command
still refuses to display local variables.
Differential Revision: https://reviews.llvm.org/D36535
llvm-svn: 310743
