https://bugs.llvm.org/show_bug.cgi?id=47580
Bug ID: 47580
Summary: [Codeview] Missing debug info for constant globals
that are not used by code
Product: libraries
Version: trunk
Hardware: PC
OS: Windows NT
Status: NEW
Severity: enhancement
Priority: P
Component: DebugInfo
Assignee: unassignedb...@nondot.org
Reporter: sylvain.a...@ubisoft.com
CC: akhu...@google.com, alexandre.ga...@ubisoft.com,
jdevliegh...@apple.com, keith.wal...@arm.com,
llvm-bugs@lists.llvm.org,
paul_robin...@playstation.sony.com, r...@google.com
Here is a test case covering several cases of the same issue:
//------------------------------------------------------------
// main.cpp
//
//------------------------------------------------------------
struct A {
static const int const_A = 3;
static constexpr int constexpr_A = 4;
static constexpr const int constexprconst_A = 5;
static const int constOutside_A;
};
const int A::constOutside_A = 6;
static const int globalStaticConst = 10;
static constexpr int globalStaticConstexpr = 11;
const int globalConst = 12;
constexpr int globalConstexpr = 13;
int main() {
A a;
return 0;
}
//------------------------------------------------------------
Compiling with clang-cl.exe:
clang-cl.exe main.cpp /nologo /EHsc- /Z7 /std:c++17 /GS- /GR- /c
/Fo:main-clangcl.obj
lld-link.exe /DEBUG main-clangcl.obj
Compiling with Microsoft's cl.exe:
cl.exe main.cpp /nologo /EHsc- /Z7 /std:c++17 /GS- /GR- /c /Fo:main-msvc.obj
main.cpp
lld-link.exe /DEBUG main-msvc.obj
In Visual Studio 2019 debugger, trying to display those values (through the
Watch Window):
1) main-MSVC.exe
-> "A" : symbol exists, can expand to display members with their value
-> "globalStaticConst" etc: displayed with value
2) main-clangcl.exe
"A" symbols exists, can expand to display members, but the values are replaced
with an error message "An unspecified error has occurred", except for
constexprconst_A (which was evaluated in main()) and constOutside_A.
Note that the behavior is the same when compiling with clang argument
`-fno-limit-debug-info`.
Comparing the output of `llvm-pdbutil dump --symbols` on both obj files, we can
see a few S_CONSTANT entries that appear on msvc but not clangcl:
Symbols
============================================================
Mod 0000 | `.debug$S`:
(...)
0 | S_CONSTANT [size = 21] `B::const_B`
type = 0x1003 (const int), value = 3
0 | S_CONSTANT [size = 25] `B::constexpr_B`
type = 0x1003 (const int), value = 4
0 | S_CONSTANT [size = 30] `B::constexprconst_B`
type = 0x1003 (const int), value = 5
etc
It would be nice to have these values shown when debugging.
If I understand correctly, the goal is to have the informations about those
constants ready at CodeViewDebug::endModule(), so that they can be emitted in
CodeViewDebug::emitDebugInfoForGlobals().
@rnk, would you know where to gather those symbols information?
--
You are receiving this mail because:
You are on the CC list for the bug._______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
