forked from OSchip/llvm-project
9a7e211e8f
This commit implements the behaviour of the SECTIONS linker script directive, used to not only define a custom mapping between input and output sections, but also order input sections in the output file. To do this, we modify DefaultLayout with hooks at important places that allow us to re-order input sections according to a custom order. We also add a hook in SegmentChunk to allow us to calculate linker script expressions while assigning virtual addresses to the input sections that live in a segment. Not all SECTIONS constructs are currently supported, but only the ones that do not use special sort orders. It adds two LIT test as practical examples of which sections directives are currently supported. In terms of high-level changes, it creates a new class "script::Sema" that owns all linker script ASTs and the logic for linker script semantics as well. ELFLinkingContext owns a single copy of Sema, which will be used throughout the object file writing process (to layout sections as proposed by the linker script). Other high-level change is that the writer no longer uses a "const" copy of the linking context. This happens because linker script expressions must be calculated *while* calculating final virtual addresses, which is a very late step in object file writing. While calculating these expressions, we need to update the linker script symbol table (inside the semantics object), and, thus, we are "modifying our context" as we prepare to write the file. http://reviews.llvm.org/D8157 llvm-svn: 232402 |
||
|---|---|---|
| .. | ||
| Config | ||
| Core | ||
| Driver | ||
| ReaderWriter | ||
| CMakeLists.txt | ||
| Makefile | ||