824c8e0593
This commit introduce SOC_MEM_NON_CONTIGUOUS_SRAM flag (that enebled for
esp32p4). If SOC_MEM_NON_CONTIGUOUS_SRAM is enabled:
- LDFLAGS+=--enable-non-contiguous-regions
- ldgen.py replaces "arrays[*]" from sections.ld.in with objects under
SURROUND keyword. (e.g. from linker.lf: data -> dram0_data SURROUND(foo))
- "mapping[*]" - refers to all other data
If SOC_MEM_NON_CONTIGUOUS_SRAM, sections.ld.in file should contain at
least one block of code like this (otherwise it does not make sense):
.dram0.bss (NOLOAD) :
{
arrays[dram0_bss]
mapping[dram0_bss]
} > sram_low
.dram1.bss (NOLOAD) :
{
/* do not place here arrays[dram0_bss] because it may be splited
* between segments */
mapping[dram0_bss]
} > sram_high
Linker Script Generator
Contains code that implements linker script generation, ldgen. For more information about the feature,
see docs/en/api-guides/linker-script-generation.rst.
Source Files
The following are the source files in the directory:
ldgen.py- Python executable that gets called during build.entity.py- contains classes related to entities (library, object, symbol or combination of the above) with mappable input sections.fragments.py- contains classes for parsing the different types of fragments in linker fragment files.generation.py- contains bulk of the logic used to process fragments into output commands.sdkconfig.py- used for evaluating conditionals in fragment files.linker_script.py- augments the input linker script template with output commands from generation process to produce the output linker script.output_commands.py- contains classes that represent the output commands in the output linker script.ldgen_common.py- contains miscellaneous utilities/definitions that can be used in the files mentioned above.
Tests
Unit tests are in the test directory. These tests are run as part of CI in the job test_ldgen_on_host.
There is also a test app for ldgen in tools/test_apps/build_system/ldgen_test.
Build System
Linker script generation is a part of the build process. The build scripts tools/cmake/ldgen.cmake
and make/ldgen.mk contain the build-system-side implementation for CMake and Make, respectively.
Basic Flow
The build system invokes ldgen.py, passing some information from the build.
The linker fragment files are parsed by fragments.py, evaluating conditional expressions
with sdkconfig.py.
From the parsed fragments, generation.py generates output commands defined in output_commands.py,
with some help from entity.py.
linker_script.py writes the output linker script, replacing markers with output commands generated.
More details about the implementation are in the respective source files.