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* https://stackoverflow.com/questions/9827157/what-does-keep-mean-in-a-linker-script | * https://stackoverflow.com/questions/9827157/what-does-keep-mean-in-a-linker-script | ||
| + | |||
| + | How to place C global variables at a particular address: | ||
| + | |||
| + | * https://global.epson.com/products_and_drivers/semicon/products/micro_controller/pdf/lnk_03e.pdf | ||
| + | * https://stackoverflow.com/questions/39998485/how-to-access-variable-define-in-linker-script-in-c | ||
| + | |||
| + | A reference to gcc linker documentation: | ||
| + | |||
| + | * https://sourceware.org/binutils/docs/ld/Source-Code-Reference.html | ||
<!-- odne komentar --> | <!-- odne komentar --> | ||
| + | |||
| + | 2024-08-05 MON | ||
| + | |||
| + | Interesting linker script macro in one of Zephy's header files . . . | ||
| + | <pre> | ||
| + | " | ||
| + | 167 | ||
| + | 168 #ifndef BUILD_ASSERT | ||
| + | 169 /* Compile-time assertion that makes the build to fail. | ||
| + | 170 * Common implementation swallows the message. | ||
| + | 171 */ | ||
| + | 172 #define BUILD_ASSERT(EXPR, MSG...) \ | ||
| + | 173 enum _CONCAT(__build_assert_enum, __COUNTER__) { \ | ||
| + | 174 _CONCAT(__build_assert, __COUNTER__) = 1 / !!(EXPR) \ | ||
| + | 175 } | ||
| + | 176 #endif | ||
| + | 177 | ||
| + | 178 /* | ||
| + | 179 * This is meant to be used in conjunction with __in_section() and similar | ||
| + | 180 * where scattered structure instances are concatenated together by the linker | ||
| + | 181 * and walked by the code at run time just like a contiguous array of such | ||
| + | 182 * structures. | ||
| + | 183 * | ||
| + | 184 * Assemblers and linkers may insert alignment padding by default whose | ||
| + | 185 * size is larger than the natural alignment for those structures when | ||
| + | 186 * gathering various section segments together, messing up the array walk. | ||
| + | 187 * To prevent this, we need to provide an explicit alignment not to rely | ||
| + | 188 * on the default that might just work by luck. | ||
| + | 189 * | ||
| + | 190 * Alignment statements in linker scripts are not sufficient as | ||
| + | 191 * the assembler may add padding by itself to each segment when switching | ||
| + | 192 * between sections within the same file even if it merges many such segments | ||
| + | 193 * into a single section in the end. | ||
| + | 194 */ | ||
| + | 195 #define Z_DECL_ALIGN(type) __aligned(__alignof(type)) type | ||
| + | 196 | ||
| + | |||
| + | "~/projects-sandbox/workspace-for-nexus/zephyr/include/zephyr/toolchain/common.h" 214 lines --99%-- | ||
| + | |||
| + | </pre> | ||
<!-- EOF --> | <!-- EOF --> | ||
Latest revision as of 18:01, 5 August 2024
GNU and LLVM linker notes.
Overview
This NN page a starting point for notes, links to external references and examples of `ld` linker scripts. As of page creation time 2024 Q1 there appear to be two major linker variants: GNU ld and LLVM linker implementation.
Introductory References
- https://lld.llvm.org/ELF/linker_script.html . . . LLVM linker documentation
Use of 'KEEP' key word in linker scripts:
How to place C global variables at a particular address:
- https://global.epson.com/products_and_drivers/semicon/products/micro_controller/pdf/lnk_03e.pdf
- https://stackoverflow.com/questions/39998485/how-to-access-variable-define-in-linker-script-in-c
A reference to gcc linker documentation:
2024-08-05 MON
Interesting linker script macro in one of Zephy's header files . . .
"
167
168 #ifndef BUILD_ASSERT
169 /* Compile-time assertion that makes the build to fail.
170 * Common implementation swallows the message.
171 */
172 #define BUILD_ASSERT(EXPR, MSG...) \
173 enum _CONCAT(__build_assert_enum, __COUNTER__) { \
174 _CONCAT(__build_assert, __COUNTER__) = 1 / !!(EXPR) \
175 }
176 #endif
177
178 /*
179 * This is meant to be used in conjunction with __in_section() and similar
180 * where scattered structure instances are concatenated together by the linker
181 * and walked by the code at run time just like a contiguous array of such
182 * structures.
183 *
184 * Assemblers and linkers may insert alignment padding by default whose
185 * size is larger than the natural alignment for those structures when
186 * gathering various section segments together, messing up the array walk.
187 * To prevent this, we need to provide an explicit alignment not to rely
188 * on the default that might just work by luck.
189 *
190 * Alignment statements in linker scripts are not sufficient as
191 * the assembler may add padding by itself to each segment when switching
192 * between sections within the same file even if it merges many such segments
193 * into a single section in the end.
194 */
195 #define Z_DECL_ALIGN(type) __aligned(__alignof(type)) type
196
"~/projects-sandbox/workspace-for-nexus/zephyr/include/zephyr/toolchain/common.h" 214 lines --99%--
