[lld] [ELF] Fix assertion in cdsort (PR #71708)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lld-elf

Author: None (spupyrev)

<details>
<summary>Changes</summary>

It seems that some functions (.text.unlikely.xxx) may have zero size, which 
makes some builds with enabled assertions fail. Removing the assertion and
extending one test to fix the build.
The sorting can process such zero-sized functions so no changes there are needed

---
Full diff: https://github.com/llvm/llvm-project/pull/71708.diff


2 Files Affected:

- (modified) lld/ELF/CallGraphSort.cpp (-1) 
- (modified) lld/test/ELF/cgprofile-txt2.s (+11) 


``````````diff
diff --git a/lld/ELF/CallGraphSort.cpp b/lld/ELF/CallGraphSort.cpp
index 5e36964da94fc52..a0cf491bbae35ba 100644
--- a/lld/ELF/CallGraphSort.cpp
+++ b/lld/ELF/CallGraphSort.cpp
@@ -287,7 +287,6 @@ DenseMap<const InputSectionBase *, int> elf::computeCacheDirectedSortOrder() {
     if (res.second) {
       // inSec does not appear before in the graph.
       sections.push_back(inSec);
-      assert(inSec->getSize() > 0 && "found a function with zero size");
       funcSizes.push_back(inSec->getSize());
       funcCounts.push_back(0);
     }
diff --git a/lld/test/ELF/cgprofile-txt2.s b/lld/test/ELF/cgprofile-txt2.s
index b59b6eeb292fabf..bb9e78a4a2e9c2b 100644
--- a/lld/test/ELF/cgprofile-txt2.s
+++ b/lld/test/ELF/cgprofile-txt2.s
@@ -5,11 +5,13 @@
 # RUN: echo "B C 50" >> %t.call_graph
 # RUN: echo "C D 40" >> %t.call_graph
 # RUN: echo "D B 10" >> %t.call_graph
+# RUN: echo "D E 1" >> %t.call_graph
 # RUN: ld.lld -e A %t --call-graph-ordering-file %t.call_graph --call-graph-profile-sort=hfsort -o %t2
 # RUN: llvm-readobj --symbols %t2 | FileCheck %s --check-prefix=CHECKC3
 # RUN: ld.lld -e A %t --call-graph-ordering-file %t.call_graph --call-graph-profile-sort=cdsort -o %t2
 # RUN: llvm-readobj --symbols %t2 | FileCheck %s --check-prefix=CHECKCDS
 
+## The expected order is [B, C, D, E, A]
 # CHECKC3:      Name: A
 # CHECKC3-NEXT: Value: 0x201123
 # CHECKC3:      Name: B
@@ -18,7 +20,10 @@
 # CHECKC3-NEXT: Value: 0x201121
 # CHECKC3:      Name: D
 # CHECKC3-NEXT: Value: 0x201122
+# CHECKC3:      Name: E
+# CHECKC3-NEXT: Value: 0x201123
 
+## The expected order is [A, B, C, D, E]
 # CHECKCDS:      Name: A
 # CHECKCDS-NEXT: Value: 0x201120
 # CHECKCDS:      Name: B
@@ -27,6 +32,8 @@
 # CHECKCDS-NEXT: Value: 0x201122
 # CHECKCDS:      Name: D
 # CHECKCDS-NEXT: Value: 0x201123
+# CHECKCDS:      Name: E
+# CHECKCDS-NEXT: Value: 0x201124
 
 .section    .text.A,"ax", at progbits
 .globl  A
@@ -47,3 +54,7 @@ C:
 .globl  D
 D:
  nop
+
+.section    .text.E,"ax", at progbits
+.globl  E
+E:

``````````

</details>


https://github.com/llvm/llvm-project/pull/71708