Revert "[LLD][ELF] Don't spill to same memory region"

[mysterymath]

Reverts #129795

[llvmbot]

@llvm/pr-subscribers-lld

@llvm/pr-subscribers-lld-elf

Author: Daniel Thornburgh (mysterymath)

Changes

Reverts llvm/llvm-project#129795

---

Full diff: https://github.com/llvm/llvm-project/pull/130815.diff

2 Files Affected:

• (modified) lld/ELF/LinkerScript.cpp (+9-25)
• (modified) lld/test/ELF/linkerscript/section-class.test (-100)

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 45c03965d9601..120f5271cf229 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -563,7 +563,7 @@ LinkerScript::computeInputSections(const InputSectionDescription *cmd,
           continue;
 
         if (!cmd->matchesFile(*sec->file) || pat.excludesFile(*sec->file) ||
-            !flagsMatch(sec))
+            sec->parent == &outCmd || !flagsMatch(sec))
           continue;
 
         if (sec->parent) {
@@ -626,7 +626,7 @@ LinkerScript::computeInputSections(const InputSectionDescription *cmd,
 
     for (InputSectionDescription *isd : scd->sc.commands) {
       for (InputSectionBase *sec : isd->sectionBases) {
-        if (!flagsMatch(sec))
+        if (sec->parent == &outCmd || !flagsMatch(sec))
           continue;
         bool isSpill = sec->parent && isa<OutputSection>(sec->parent);
         if (!sec->parent || (isSpill && outCmd.name == "/DISCARD/")) {
@@ -1585,32 +1585,16 @@ bool LinkerScript::spillSections() {
         if (isa<PotentialSpillSection>(isec))
           continue;
 
+        // Find the next potential spill location and remove it from the list.
         auto it = potentialSpillLists.find(isec);
         if (it == potentialSpillLists.end())
-          break;
-
-        // Consume spills until finding one that might help, then consume it.
-        PotentialSpillList &list = it->second;
-        PotentialSpillSection *spill;
-        for (spill = list.head; spill; spill = spill->next) {
-          if (list.head->next)
-            list.head = spill->next;
-          else
-            potentialSpillLists.erase(isec);
-
-          // Spills to the same region that overflowed cannot help.
-          if (hasRegionOverflowed(osec->memRegion) &&
-              spill->getParent()->memRegion == osec->memRegion)
-            continue;
-          if (hasRegionOverflowed(osec->lmaRegion) &&
-              spill->getParent()->lmaRegion == osec->lmaRegion)
-            continue;
-
-          // This spill might resolve the overflow.
-          break;
-        }
-        if (!spill)
           continue;
+        PotentialSpillList &list = it->second;
+        PotentialSpillSection *spill = list.head;
+        if (spill->next)
+          list.head = spill->next;
+        else
+          potentialSpillLists.erase(isec);
 
         // Replace the next spill location with the spilled section and adjust
         // its properties to match the new location. Note that the alignment of
diff --git a/lld/test/ELF/linkerscript/section-class.test b/lld/test/ELF/linkerscript/section-class.test
index 27273f3855c32..5c30b6343653e 100644
--- a/lld/test/ELF/linkerscript/section-class.test
+++ b/lld/test/ELF/linkerscript/section-class.test
@@ -450,103 +450,3 @@ SECTIONS {
 
 # TO-DISCARD: error: section '.two_byte_section' cannot spill from/to /DISCARD/
 # TO-DISCARD-WARN: warning: section '.two_byte_section' cannot spill from/to /DISCARD/
-
-#--- same-mem-region.lds
-## Spills to the same memory region that overflowed do not consume address assignment passes.
-MEMORY {
-  a : ORIGIN = 0, LENGTH = 0
-  b : ORIGIN = 0, LENGTH = 3
-  c : ORIGIN = 3, LENGTH = 3
-  d : ORIGIN = 6, LENGTH = 3
-}
-SECTIONS {
-  CLASS(class) { *(.one_byte_section .two_byte_section) }
-  .a00 : { CLASS(class) } >a AT>c
-  .a01 : { CLASS(class) } >a AT>d
-  .a02 : { CLASS(class) } >a AT>d
-  .a03 : { CLASS(class) } >a AT>d
-  .a04 : { CLASS(class) } >a AT>d
-  .a05 : { CLASS(class) } >a AT>d
-  .a06 : { CLASS(class) } >a AT>d
-  .a07 : { CLASS(class) } >a AT>d
-  .a08 : { CLASS(class) } >a AT>d
-  .a09 : { CLASS(class) } >a AT>d
-  .a10 : { CLASS(class) } >a AT>d
-  .a11 : { CLASS(class) } >a AT>d
-  .a12 : { CLASS(class) } >a AT>d
-  .a13 : { CLASS(class) } >a AT>d
-  .a14 : { CLASS(class) } >a AT>d
-  .a15 : { CLASS(class) } >a AT>d
-  .a16 : { CLASS(class) } >a AT>d
-  .a17 : { CLASS(class) } >a AT>d
-  .a18 : { CLASS(class) } >a AT>d
-  .a19 : { CLASS(class) } >a AT>d
-  .a20 : { CLASS(class) } >a AT>d
-  .a21 : { CLASS(class) } >a AT>d
-  .a22 : { CLASS(class) } >a AT>d
-  .a23 : { CLASS(class) } >a AT>d
-  .a24 : { CLASS(class) } >a AT>d
-  .a25 : { CLASS(class) } >a AT>d
-  .a26 : { CLASS(class) } >a AT>d
-  .a27 : { CLASS(class) } >a AT>d
-  .a28 : { CLASS(class) } >a AT>d
-  .a29 : { CLASS(class) } >a AT>d
-  .a30 : { CLASS(class) } >a AT>d
-  .b : { CLASS(class) } >b AT>d
-}
-
-# RUN: ld.lld -T same-mem-region.lds -o same-mem-region spill.o
-# RUN: llvm-readelf -S same-mem-region | FileCheck %s --check-prefix=SAME-MEM-REGION
-
-# SAME-MEM-REGION:      Name          Type     Address          Off    Size
-# SAME-MEM-REGION:      .b PROGBITS 0000000000000000 001000 000003
-
-#--- same-lma-region.lds
-## Spills to the same load region that overflowed do not consume address assignment passes.
-MEMORY {
-  a : ORIGIN = 0, LENGTH = 0
-  b : ORIGIN = 0, LENGTH = 3
-  c : ORIGIN = 3, LENGTH = 3
-  d : ORIGIN = 6, LENGTH = 3
-}
-SECTIONS {
-  CLASS(class) { *(.one_byte_section .two_byte_section) }
-  .a00 : { CLASS(class) } >c AT>a
-  .a01 : { CLASS(class) } >d AT>a
-  .a02 : { CLASS(class) } >d AT>a
-  .a03 : { CLASS(class) } >d AT>a
-  .a04 : { CLASS(class) } >d AT>a
-  .a05 : { CLASS(class) } >d AT>a
-  .a06 : { CLASS(class) } >d AT>a
-  .a07 : { CLASS(class) } >d AT>a
-  .a08 : { CLASS(class) } >d AT>a
-  .a09 : { CLASS(class) } >d AT>a
-  .a10 : { CLASS(class) } >d AT>a
-  .a11 : { CLASS(class) } >d AT>a
-  .a12 : { CLASS(class) } >d AT>a
-  .a13 : { CLASS(class) } >d AT>a
-  .a14 : { CLASS(class) } >d AT>a
-  .a15 : { CLASS(class) } >d AT>a
-  .a16 : { CLASS(class) } >d AT>a
-  .a17 : { CLASS(class) } >d AT>a
-  .a18 : { CLASS(class) } >d AT>a
-  .a19 : { CLASS(class) } >d AT>a
-  .a20 : { CLASS(class) } >d AT>a
-  .a21 : { CLASS(class) } >d AT>a
-  .a22 : { CLASS(class) } >d AT>a
-  .a23 : { CLASS(class) } >d AT>a
-  .a24 : { CLASS(class) } >d AT>a
-  .a25 : { CLASS(class) } >d AT>a
-  .a26 : { CLASS(class) } >d AT>a
-  .a27 : { CLASS(class) } >d AT>a
-  .a28 : { CLASS(class) } >d AT>a
-  .a29 : { CLASS(class) } >d AT>a
-  .a30 : { CLASS(class) } >d AT>a
-  .b : { CLASS(class) } >d AT>b
-}
-
-# RUN: ld.lld -T same-lma-region.lds -o same-lma-region spill.o
-# RUN: llvm-readelf -S same-lma-region | FileCheck %s --check-prefix=SAME-LMA-REGION
-
-# SAME-LMA-REGION:      Name          Type     Address          Off    Size
-# SAME-LMA-REGION:      .b PROGBITS 0000000000000006 001006 000003