[llvm] [ThinLTO] Populate declaration import status except for distributed ThinLTO under a default-off new option (PR #88024)

[Mingming Liu via llvm-commits]

================
@@ -0,0 +1,180 @@
+; "-debug-only" requires asserts.
+; REQUIRES: asserts
+; RUN: rm -rf %t && split-file %s %t && cd %t
+
+; Generate per-module summaries.
+; RUN: opt -module-summary main.ll -o main.bc
+; RUN: opt -module-summary lib.ll -o lib.bc
+
+; Generate the combined summary and distributed indices.
+
+; - For function import, set 'import-instr-limit' to 7 and fall back to import
+;   function declarations.
+; - In main.ll, function 'main' calls 'small_func' and 'large_func'. Both callees
+;   are defined in lib.ll. 'small_func' has two indirect callees, one is smaller
+;   and the other one is larger. Both callees of 'small_func' are defined in lib.ll.
+; - Given the import limit, in main's combined summary, the import type of 'small_func'
+;   and 'small_indirect_callee' will be 'definition', and the import type of
+;   'large_func' and 'large_indirect_callee' will be 'declaration'.
+;
+; The test will disassemble combined summaries and check the import type is
+; correct. Right now postlink optimizer pipeline doesn't do anything (e.g.,
+; import the declaration or de-serialize summary attributes yet) so there is
+; nothing to test more than the summary content.
+;
+; TODO: Extend this test case to test IR once postlink optimizer makes use of
+; the import type for declarations.
+;
+; RUN: llvm-lto2 run \
+; RUN:   -debug-only=function-import \
+; RUN:   -import-instr-limit=7 \
+; RUN:   -import-declaration \
+; RUN:   -thinlto-distributed-indexes \
+; RUN:   -r=main.bc,main,px \
+; RUN:   -r=main.bc,small_func, \
+; RUN:   -r=main.bc,large_func, \
+; RUN:   -r=lib.bc,callee,pl \
+; RUN:   -r=lib.bc,large_indirect_callee,px \
+; RUN:   -r=lib.bc,small_func,px \
+; RUN:   -r=lib.bc,large_func,px \
+; RUN:   -r=lib.bc,large_indirect_callee_alias,px \
+; RUN:   -r=lib.bc,calleeAddrs,px -o summary main.bc lib.bc 2>&1 | FileCheck %s --check-prefix=DUMP
+;
+; RUN: llvm-lto -thinlto-action=thinlink -import-declaration -import-instr-limit=7  -o combined.index.bc main.bc lib.bc
+; RUN: llvm-lto -thinlto-action=distributedindexes -debug-only=function-import -import-declaration -import-instr-limit=7 -thinlto-index combined.index.bc main.bc lib.bc 2>&1 | FileCheck %s --check-prefix=DUMP
+
+; DUMP: - 2 function definitions and 3 function declarations imported from lib.bc
+
+; First disassemble per-module summary and find out the GUID for {large_func, large_indirect_callee}.
+;
+; RUN: llvm-dis lib.bc -o - | FileCheck %s --check-prefix=LIB-DIS
+; LIB-DIS: [[LARGEFUNC:\^[0-9]+]] = gv: (name: "large_func", summaries: {{.*}}) ; guid = 2418497564662708935
+; LIB-DIS: [[LARGEINDIRECT:\^[0-9]+]] = gv: (name: "large_indirect_callee", summaries: {{.*}}) ; guid = 14343440786664691134
+; LIB-DIS: [[LARGEINDIRECTALIAS:\^[0-9]+]] = gv: (name: "large_indirect_callee_alias", summaries: {{.*}}, aliasee: [[LARGEINDIRECT]]
+;
+; Secondly disassemble main's combined summary and test that large callees are
+; not imported as declarations yet.
+; TODO: Serialize declaration bit and test declaration bits are correctly set.
+;
+; RUN: llvm-dis main.bc.thinlto.bc -o - | FileCheck %s --check-prefix=MAIN-DIS
+;
+; MAIN-DIS: [[LIBMOD:\^[0-9]+]] = module: (path: "lib.bc", hash: (0, 0, 0, 0, 0))
+; MAIN-DIS-NOT: [[LARGEFUNC:\^[0-9]+]] = gv: (guid: 2418497564662708935, summaries: (function: (module: [[LIBMOD]], flags: ({{.*}} importType: declaration), insts: 8, {{.*}})))
+; MAIN-DIS-NOT: [[LARGEINDIRECT:\^[0-9]+]] = gv: (guid: 14343440786664691134, summaries: (function: (module: [[LIBMOD]], flags: ({{.*}} importType: declaration), insts: 8, {{.*}})))
+; MAIN-DIS-NOT: [[LARGEINDIRECTALIAS:\^[0-9]+]] = gv: (guid: 16730173943625350469, summaries: (alias: (module: [[LIBMOD]], flags: ({{.*}} importType: declaration)
+
+; Run in-process ThinLTO and tests that
+; 1. `callee` remains internalized even if the symbols of its callers
+; (large_func and large_indirect_callee) are exported as declarations and visible to main module.
+; 2. the debugging logs from `function-import` pass are expected.
+
+; RUN: llvm-lto2 run \
+; RUN:   -debug-only=function-import \
+; RUN:   -save-temps \
+; RUN:   -import-instr-limit=7 \
+; RUN:   -import-declaration \
+; RUN:   -r=main.bc,main,px \
+; RUN:   -r=main.bc,small_func, \
+; RUN:   -r=main.bc,large_func, \
+; RUN:   -r=lib.bc,callee,pl \
+; RUN:   -r=lib.bc,large_indirect_callee,px \
+; RUN:   -r=lib.bc,small_func,px \
+; RUN:   -r=lib.bc,large_func,px \
+; RUN:   -r=lib.bc,large_indirect_callee_alias,px \
+; RUN:   -r=lib.bc,calleeAddrs,px -o in-process main.bc lib.bc 2>&1 | FileCheck %s --check-prefix=IMPORTDUMP
+
+; IMPORTDUMP: Not importing function 11825436545918268459 callee from lib.cc
+; IMPORTDUMP: Is importing function declaration 14343440786664691134 large_indirect_callee from lib.cc
+; IMPORTDUMP: Is importing function definition 13568239288960714650 small_indirect_callee from lib.cc
+; IMPORTDUMP: Is importing function definition 6976996067367342685 small_func from lib.cc
+; IMPORTDUMP: Is importing function declaration 2418497564662708935 large_func from lib.cc
+; IMPORTDUMP: Not importing global 7680325410415171624 calleeAddrs from lib.cc
+; IMPORTDUMP: Is importing alias declaration 16730173943625350469 large_indirect_callee_alias from lib.cc
+
+; RUN: llvm-dis in-process.1.3.import.bc -o - | FileCheck %s --check-prefix=IMPORT
+
+; RUN: llvm-dis in-process.2.2.internalize.bc -o - | FileCheck %s --check-prefix=INTERNALIZE
+
+; IMPORT-DAG: define available_externally void @small_func
+; IMPORT-DAG: define available_externally hidden void @small_indirect_callee
+; IMPORT-DAG: declare void @large_func
+; IMPORT-NOT: large_indirect_callee
----------------
minglotus-6 wrote:

sounds good. I somehow didn't find the existingTODO when we discussed the follow-up plans (import declaration [implementation and test](https://github.com/llvm/llvm-project/compare/main...minglotus-6:llvm-project:irlinker) in my llvm fork), and yesterday I thought I deleted them mistakenly when updating PRs.

Turns out there are two TODOs on line 25 and line 57, so gathered them here.

https://github.com/llvm/llvm-project/pull/88024