AIESW-27905: special handling for hint_bitmap 0 preemption point by HimanshuChoudhary-Xilinx · Pull Request #292 · Xilinx/aiebu

HimanshuChoudhary-Xilinx · 2026-05-19T11:52:45Z

Problem solved by the commit

AIE4 preemption: emit dummy save/restore jobs when hint_bitmap is zero

Problem
When a PREEMPT opcode references a hintmap with the scratchpad size zero — implementation still injected the full save/restore job template for the zero-size case, which included:

BD configuration (with zero-length DMA buffer descriptors)
Stream-switch set/clear routing

This was wasteful and incorrect: even though the BDs carried zero length, the surrounding stream-switch and DMA infrastructure was still emitted.

Dummy save and restore controlcode added:
save:

START_JOB 0
  NOP
END_JOB
EOF

restore:

START_JOB 0
  LOAD_LAST_PDI
END_JOB
EOF

Tests
Two new test cases are added under test/aie4-ctrlcode/:

1col_preempt_0hint
3col_preempt_0hint

Bug / issue (if any) fixed, which PR introduced the bug, how it was discovered

How problem was solved, alternative solutions (if any) and why they were rejected

Risks (if any) associated the changes in the commit

What has been tested and how, request additional testing if necessary

Documentation impact (if any)

Copilot

Pull request overview

This PR adds special handling in the AIE4 ASM preprocessor for PREEMPT points whose hint_bitmap is all-zero. Since such hintmaps require zero scratchpad, the parser now injects minimal dummy save (NOP) / restore (LOAD_LAST_PDI) jobs instead of expanding the full BD / stream-switch save/restore templates, providing valid label targets for the PREEMPT opcode without unnecessary work. Two new ctrlcode tests (1-column and 3-column) exercise the mixed zero/non-zero hintmap scenario, and the existing fused_hw_package_subgraph_0 golden md5 is updated to reflect the new behavior. The header generator is also tightened to emit a const global map.

Changes:

Inject minimal dummy save/restore jobs when grp.size == 0 (zero hint_bitmap) in inject_hintmap_save_restore.
Add 1col_preempt_0hint and 3col_preempt_0hint test fixtures (asm/config/CMake/gold.md5) and register them in the parent CMakeLists.
Mark the generated aie4_save_restore_map and accessor return type as const in generate_aie4_header.py; update the existing fused_hw_package_subgraph_0 gold.md5.

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/cpp/preprocessor/asm/asm_parser.cpp	Adds zero-hintmap fast path emitting dummy save/restore jobs with proper labels.
specification/aie4/preemption_asm/generate_aie4_header.py	Makes the generated save/restore map and accessor return type `const`.
test/aie4-ctrlcode/CMakeLists.txt	Registers the two new preempt_0hint test directories.
test/aie4-ctrlcode/1col_preempt_0hint/{CMakeLists.txt,config.json,test.asm,pdi.asm,gold.md5}	New 1-column test exercising mixed zero/non-zero hintmaps.
test/aie4-ctrlcode/3col_preempt_0hint/{CMakeLists.txt,config.json,test.asm,uc0.asm,uc2.asm,uc4.asm,pdi.asm,gold.md5}	New 3-column test exercising mixed zero/non-zero hintmaps across groups.
test/aie4-ctrlcode/compile_time/fused_hw_package_subgraph_0/gold.md5	Updated golden hash reflecting new zero-hintmap codegen behavior.

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github-actions

clang-tidy made some suggestions

github-actions · 2026-05-19T11:57:27Z

@@ -9,7 +9,7 @@
 #include <cstdint>

 // C++17 inline variable - single instance across all translation units
-inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_shimbd_map = {
+inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_shimbd_map = {


warning: expected unqualified-id [clang-diagnostic-error]

inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_shimbd_map = { ^

github-actions · 2026-05-19T11:57:27Z

@@ -9,7 +9,7 @@
 #include <cstdint>

 // C++17 inline variable - single instance across all translation units
-inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_shimbd_map = {
+inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_shimbd_map = {


warning: no member named 'string' in namespace 'std' [clang-diagnostic-error]

inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_shimbd_map = { ^

github-actions · 2026-05-19T11:57:27Z

@@ -21,13 +21,13 @@ inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::s
  {14, {{"DMAWRITE_data_125", "DMAWRITE_data_126"}, {"DMAWRITE_data_0", "DMAWRITE_data_1", "DMAWRITE_data_2", "DMAWRITE_data_3"}}}
 };

-inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>&
+inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>&


warning: expected unqualified-id [clang-diagnostic-error]

inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>& ^

github-actions · 2026-05-19T11:57:27Z

@@ -21,13 +21,13 @@ inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::s
  {14, {{"DMAWRITE_data_125", "DMAWRITE_data_126"}, {"DMAWRITE_data_0", "DMAWRITE_data_1", "DMAWRITE_data_2", "DMAWRITE_data_3"}}}
 };

-inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>&
+inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>&


warning: no member named 'string' in namespace 'std' [clang-diagnostic-error]

inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>& ^

github-actions · 2026-05-19T11:57:27Z

 get_aie4_save_restore_shimbd()
 {
  return aie4_save_restore_shimbd_map;
 }

-inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_membd_map = {
+inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_membd_map = {


warning: expected unqualified-id [clang-diagnostic-error]

inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_membd_map = { ^

github-actions · 2026-05-19T11:57:28Z

 get_aie4_save_restore_shimbd()
 {
  return aie4_save_restore_shimbd_map;
 }

-inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_membd_map = {
+inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_membd_map = {


warning: no member named 'string' in namespace 'std' [clang-diagnostic-error]

inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_membd_map = { ^

github-actions · 2026-05-19T11:57:28Z

@@ -39,13 +39,13 @@ inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::s
  {14, {{"DMAWRITE_data_127", "DMAWRITE_data_128"}, {"DMAWRITE_data_4", "DMAWRITE_data_5", "DMAWRITE_data_6", "DMAWRITE_data_7"}}}
 };

-inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>&
+inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>&


warning: expected unqualified-id [clang-diagnostic-error]

inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>& ^

github-actions · 2026-05-19T11:57:28Z

@@ -39,13 +39,13 @@ inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::s
  {14, {{"DMAWRITE_data_127", "DMAWRITE_data_128"}, {"DMAWRITE_data_4", "DMAWRITE_data_5", "DMAWRITE_data_6", "DMAWRITE_data_7"}}}
 };

-inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>&
+inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>&


warning: no member named 'string' in namespace 'std' [clang-diagnostic-error]

inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>>& ^

github-actions · 2026-05-19T11:57:28Z

 get_aie4_save_restore_membd()
 {
  return aie4_save_restore_membd_map;
 }

-inline std::map<uint32_t, std::pair<std::vector<uint8_t>, std::vector<uint8_t>>> aie4_save_restore_map = {
+inline const std::map<uint32_t, std::pair<std::vector<uint8_t>, std::vector<uint8_t>>> aie4_save_restore_map = {


warning: initialization of 'aie4_save_restore_map' with static storage duration may throw an exception that cannot be caught [cert-err58-cpp]

inline const std::map<uint32_t, std::pair<std::vector<uint8_t>, std::vector<uint8_t>>> aie4_save_restore_map = { ^

Additional context

/usr/include/c++/13/bits/stl_map.h:239: possibly throwing constructor declared here

map(initializer_list<value_type> __l, ^

Signed-off-by: Himanshu Choudhary <Himanshu.Choudhary@amd.com>

github-actions

clang-tidy made some suggestions

github-actions · 2026-05-25T12:17:16Z


 // C++17 inline variable - single instance across all translation units
-inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_shimbd_map = {
+inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_shimbd_map = {


warning: initialization of 'aie4_save_restore_shimbd_map' with static storage duration may throw an exception that cannot be caught [cert-err58-cpp]

inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_shimbd_map = { ^

Additional context

/usr/include/c++/13/bits/stl_map.h:239: possibly throwing constructor declared here

map(initializer_list<value_type> __l, ^

github-actions · 2026-05-25T12:17:16Z

 get_aie4_save_restore_shimbd()
 {
  return aie4_save_restore_shimbd_map;
 }

-inline std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_membd_map = {
+inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_membd_map = {


warning: initialization of 'aie4_save_restore_membd_map' with static storage duration may throw an exception that cannot be caught [cert-err58-cpp]

inline const std::map<uint32_t, std::pair<std::vector<std::string>, std::vector<std::string>>> aie4_save_restore_membd_map = { ^

Additional context

/usr/include/c++/13/bits/stl_map.h:239: possibly throwing constructor declared here

map(initializer_list<value_type> __l, ^

Copilot AI review requested due to automatic review settings May 19, 2026 11:52

Copilot started reviewing on behalf of HimanshuChoudhary-Xilinx May 19, 2026 11:52 View session

Copilot AI reviewed May 19, 2026

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github-actions Bot reviewed May 19, 2026

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HimanshuChoudhary-Xilinx mentioned this pull request May 19, 2026

update save/restore preemption asm annotation points #287

Merged

HimanshuChoudhary-Xilinx requested review from larry9523, sonals and xuhz May 20, 2026 08:22

xuhz approved these changes May 20, 2026

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HimanshuChoudhary-Xilinx added 2 commits May 25, 2026 16:52

AIESW-27905: special handling for hint_bitmap 0 preemption point

1e54ad7

Signed-off-by: Himanshu Choudhary <Himanshu.Choudhary@amd.com>

fix generate_aie4_header.py script

86d01f6

Signed-off-by: Himanshu Choudhary <Himanshu.Choudhary@amd.com>

HimanshuChoudhary-Xilinx force-pushed the hint0 branch from c17fdd0 to 86d01f6 Compare May 25, 2026 12:12

github-actions Bot reviewed May 25, 2026

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HimanshuChoudhary-Xilinx merged commit 0855416 into Xilinx:main-ge May 26, 2026
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How problem was solved, alternative solutions (if any) and why they were rejected

Risks (if any) associated the changes in the commit

What has been tested and how, request additional testing if necessary

Documentation impact (if any)

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HimanshuChoudhary-Xilinx commented May 19, 2026 •

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