Sections must start at page boundaries in memory, but they
can be aligned to sector boundaries (512-bytes) on disk.
We aligned them to 4096-byte boundaries even on disk, so we
wasted disk space a bit.
llvm-svn: 244691
__ImageBase is a special symbol whose value is the image base address.
Previously, we handled __ImageBase symbol as an absolute symbol.
Absolute symbols point to specific locations in memory and the locations
never change even if an image is base-relocated. That means that we
don't have base relocation entries for absolute symbols.
This is not a case for __ImageBase. If an image is base-relocated, its
base address changes, and __ImageBase needs to be shifted as well.
So we have to have base relocations for __ImageBase. That means that
__ImageBase is not really an absolute symbol but a different kind of
symbol.
In this patch, I introduced a new type of symbol -- DefinedRelative.
DefinedRelative is similar to DefinedAbsolute, but it has not a VA but RVA
and is a subject of base relocation. Currently only __ImageBase is of
the new symbol type.
llvm-svn: 243176
The previous logic to find default entry name or subsystem does not
seem correct (i.e. was not compatible with MSVC linker). Previously,
default entry name was inferred from CRT functions and user-defined
entry functions. Subsystem was inferred from CRT functions.
Default entry name and subsystem are now inferred based on the
following table. Note that we no longer use CRT functions to infer
them.
Entry name Subsystem
main mainCRTStartup console
wmain wmainCRTStartup console
WinMain WinMainCRTStartup windows
wWinMain wWinMainCRTStartup windows
llvm-svn: 240922
We skip unknown options in the command line with a warning message
being printed out, but we shouldn't do that for .drectve section.
The section is not visible to the user. We should handle unknown
options as an error.
llvm-svn: 240067
PE/COFF executables/DLLs usually contain data which is called
base relocations. Base relocations are a list of addresses that
need to be fixed by the loader if load-time relocation is needed.
Base relocations are in .reloc section.
We emit one base relocation entry for each IMAGE_REL_AMD64_ADDR64
relocation.
In order to save disk space, base relocations are grouped by page.
Each group is called a block. A block starts with a 32-bit page
address followed by 16-bit offsets in the page. That is more
efficient representation of addresses than just an array of 32-bit
addresses.
llvm-svn: 239710
Rui Ueyama