[WebAssembly] Add support for named data sections in wasm binaries

Followup to https://reviews.llvm.org/D91769 which added support
for names globals.

Differential Revision: https://reviews.llvm.org/D92909

11 files changed, 66 insertions, 5 deletions

diff --git a/lld/test/wasm/call-indirect.ll b/lld/test/wasm/call-indirect.ll
index 84a84710f2ba..4acc1edae4f2 100644
--- a/lld/test/wasm/call-indirect.ll
+++ b/lld/test/wasm/call-indirect.ll
@@ -156,4 +156,7 @@ define void @call_ptr(i64 (i64)* %arg) {
 ; CHECK-NEXT:     GlobalNames:
 ; CHECK-NEXT:       - Index:           0
 ; CHECK-NEXT:         Name:            __stack_pointer
+; CHECK-NEXT:     DataSegmentNames:
+; CHECK-NEXT:       - Index:           0
+; CHECK-NEXT:         Name:            .data
 ; CHECK-NEXT: ...
diff --git a/lld/test/wasm/data-segment-merging.ll b/lld/test/wasm/data-segment-merging.ll
index bc347d193574..1dee1ccbda29 100644
--- a/lld/test/wasm/data-segment-merging.ll
+++ b/lld/test/wasm/data-segment-merging.ll
@@ -31,7 +31,9 @@
 ; MERGE-NEXT:    GlobalNames:
 ; MERGE-NEXT:      - Index:           0
 ; MERGE-NEXT:        Name:            __stack_pointer
-; MERGE-NOT:       - Index:
+; MERGE-NEXT:    DataSegmentNames:
+; MERGE-NEXT:      - Index:           0
+; MERGE-NEXT:        Name:            .rodata
 
 ; RUN: wasm-ld -no-gc-sections --no-entry --no-merge-data-segments -o %t.separate.wasm %t.o
 ; RUN: obj2yaml %t.separate.wasm | FileCheck %s --check-prefix=SEPARATE
@@ -71,7 +73,9 @@
 ; SEPARATE-NEXT:    GlobalNames:
 ; SEPARATE-NEXT:      - Index:           0
 ; SEPARATE-NEXT:        Name:            __stack_pointer
-; SEPARATE-NOT:       - Index:
+; SEPARATE-NEXT:    DataSegmentNames:
+; SEPARATE-NEXT:      - Index:           0
+; SEPARATE-NEXT:        Name:            .rodata
 
 ; RUN: wasm-ld -no-gc-sections --no-entry --shared-memory --max-memory=131072 -o %t.merged.passive.wasm %t.passive.o
 ; RUN: obj2yaml %t.merged.passive.wasm | FileCheck %s --check-prefix=PASSIVE-MERGE
diff --git a/lld/test/wasm/gc-sections.ll b/lld/test/wasm/gc-sections.ll
index 8bac2fd07827..de8298697bf1 100644
--- a/lld/test/wasm/gc-sections.ll
+++ b/lld/test/wasm/gc-sections.ll
@@ -87,6 +87,9 @@ entry:
 ; CHECK-NEXT:         Name:            __stack_pointer
 ; CHECK-NEXT:       - Index:           1
 ; CHECK-NEXT:         Name:            used_global
+; CHECK-NEXT:     DataSegmentNames:
+; CHECK-NEXT:       - Index:           0
+; CHECK-NEXT:         Name:            .data
 ; CHECK-NEXT: ...
 
 ; RUN: wasm-ld -print-gc-sections --no-gc-sections -o %t1.no-gc.wasm \
@@ -162,6 +165,9 @@ entry:
 ; NO-GC-NEXT:         Name:            unused_global
 ; NO-GC-NEXT:       - Index:           2
 ; NO-GC-NEXT:         Name:            used_global
+; NO-GC-NEXT:     DataSegmentNames:
+; NO-GC-NEXT:       - Index:           0
+; NO-GC-NEXT:         Name:            .data
 ; NO-GC-NEXT: ...
 
 ; RUN: not wasm-ld --gc-sections --relocatable -o %t1.no-gc.wasm %t.o 2>&1 | FileCheck %s -check-prefix=CHECK-ERROR
diff --git a/lld/test/wasm/local-symbols.ll b/lld/test/wasm/local-symbols.ll
index d0a520a950a2..13c200d648e9 100644
--- a/lld/test/wasm/local-symbols.ll
+++ b/lld/test/wasm/local-symbols.ll
@@ -97,4 +97,7 @@ entry:
 ; CHECK-NEXT:     GlobalNames:
 ; CHECK-NEXT:       - Index:           0
 ; CHECK-NEXT:         Name:            __stack_pointer
+; CHECK-NEXT:     DataSegmentNames:
+; CHECK-NEXT:       - Index:           0
+; CHECK-NEXT:         Name:            .data
 ; CHECK-NEXT: ...
diff --git a/lld/test/wasm/locals-duplicate.test b/lld/test/wasm/locals-duplicate.test
index dc6b9c88be29..07abb7485381 100644
--- a/lld/test/wasm/locals-duplicate.test
+++ b/lld/test/wasm/locals-duplicate.test
@@ -212,6 +212,9 @@
 ; CHECK-NEXT:     GlobalNames:
 ; CHECK-NEXT:       - Index:           0
 ; CHECK-NEXT:         Name:            __stack_pointer
+; CHECK-NEXT:     DataSegmentNames:
+; CHECK-NEXT:       - Index:           0
+; CHECK-NEXT:         Name:            .data
 ; CHECK-NEXT: ...
 
 
@@ -546,4 +549,11 @@
 ; RELOC-NEXT:         Name:            get_func2B
 ; RELOC-NEXT:       - Index:           17
 ; RELOC-NEXT:         Name:            get_func3B
+; RELOC-NEXT:     DataSegmentNames:
+; RELOC-NEXT:       - Index:           0
+; RELOC-NEXT:         Name:            .data.colliding_global1
+; RELOC-NEXT:       - Index:           1
+; RELOC-NEXT:         Name:            .data.colliding_global2
+; RELOC-NEXT:       - Index:           2
+; RELOC-NEXT:         Name:            .data.colliding_global3
 ; RELOC-NEXT: ...
diff --git a/lld/test/wasm/map-file.s b/lld/test/wasm/map-file.s
index e194662ea5d1..a5bd01605695 100644
--- a/lld/test/wasm/map-file.s
+++ b/lld/test/wasm/map-file.s
@@ -40,7 +40,7 @@ somedata:
 # CHECK-NEXT:     400       5a        4         {{.*}}{{/|\\}}map-file.s.tmp1.o:(.data.somedata)
 # CHECK-NEXT:     400       5a        4                 somedata
 # CHECK-NEXT:       -       60       12 CUSTOM(.debug_info)
-# CHECK-NEXT:       -       72       2b CUSTOM(name)
+# CHECK-NEXT:       -       72       35 CUSTOM(name)
 
 # RUN: not wasm-ld %t1.o -o /dev/null -Map=/ 2>&1 \
 # RUN:  | FileCheck -check-prefix=FAIL %s
diff --git a/lld/test/wasm/signature-mismatch.ll b/lld/test/wasm/signature-mismatch.ll
index 3e42a74d0f05..d5f95b0073c0 100644
--- a/lld/test/wasm/signature-mismatch.ll
+++ b/lld/test/wasm/signature-mismatch.ll
@@ -55,6 +55,9 @@ declare i32 @ret32(i32, i64, i32) local_unnamed_addr
 ; YAML-NEXT:     GlobalNames:
 ; YAML-NEXT:       - Index:           0
 ; YAML-NEXT:         Name:            __stack_pointer
+; YAML-NEXT:     DataSegmentNames:
+; YAML-NEXT:       - Index:           0
+; YAML-NEXT:         Name:            .data
 ; YAML-NEXT: ...
 
 ;      RELOC:     Name:            linking
diff --git a/lld/test/wasm/weak-symbols.s b/lld/test/wasm/weak-symbols.s
index 41c8a1a38f55..7557dfb5535b 100644
--- a/lld/test/wasm/weak-symbols.s
+++ b/lld/test/wasm/weak-symbols.s
@@ -116,4 +116,7 @@ _start:
 # CHECK-NEXT:     GlobalNames:
 # CHECK-NEXT:       - Index:           0
 # CHECK-NEXT:         Name:            __stack_pointer
+# CHECK-NEXT:     DataSegmentNames:
+# CHECK-NEXT:       - Index:           0
+# CHECK-NEXT:         Name:            .data
 # CHECK-NEXT: ...
diff --git a/lld/wasm/SyntheticSections.cpp b/lld/wasm/SyntheticSections.cpp
index 3fdcc6252fd9..95a48528db9e 100644
--- a/lld/wasm/SyntheticSections.cpp
+++ b/lld/wasm/SyntheticSections.cpp
@@ -562,6 +562,16 @@ unsigned NameSection::numNamedGlobals() const {
   return numNames;
 }
 
+unsigned NameSection::numNamedDataSegments() const {
+  unsigned numNames = 0;
+
+  for (const OutputSegment *s : segments)
+    if (!s->name.empty())
+      ++numNames;
+
+  return numNames;
+}
+
 // Create the custom "name" section containing debug symbol names.
 void NameSection::writeBody() {
   unsigned count = numNamedFunctions();
@@ -619,6 +629,19 @@ void NameSection::writeBody() {
 
     sub.writeTo(bodyOutputStream);
   }
+
+  count = numNamedDataSegments();
+  if (count) {
+    SubSection sub(WASM_NAMES_DATA_SEGMENT);
+    writeUleb128(sub.os, count, "name count");
+
+    for (OutputSegment *s : segments) {
+      writeUleb128(sub.os, s->index, "global index");
+      writeStr(sub.os, s->name, "segment name");
+    }
+
+    sub.writeTo(bodyOutputStream);
+  }
 }
 
 void ProducersSection::addInfo(const WasmProducerInfo &info) {
diff --git a/lld/wasm/SyntheticSections.h b/lld/wasm/SyntheticSections.h
index f9ec7f288dbd..56ba66ffc08d 100644
--- a/lld/wasm/SyntheticSections.h
+++ b/lld/wasm/SyntheticSections.h
@@ -296,7 +296,9 @@ protected:
 // Create the custom "name" section containing debug symbol names.
 class NameSection : public SyntheticSection {
 public:
-  NameSection() : SyntheticSection(llvm::wasm::WASM_SEC_CUSTOM, "name") {}
+  NameSection(ArrayRef<OutputSegment *> segments)
+      : SyntheticSection(llvm::wasm::WASM_SEC_CUSTOM, "name"),
+        segments(segments) {}
   bool isNeeded() const override {
     return !config->stripDebug && !config->stripAll && numNames() > 0;
   }
@@ -304,6 +306,10 @@ public:
   unsigned numNames() const { return numNamedGlobals() + numNamedFunctions(); }
   unsigned numNamedGlobals() const;
   unsigned numNamedFunctions() const;
+  unsigned numNamedDataSegments() const;
+
+protected:
+  ArrayRef<OutputSegment *> segments;
 };
 
 class ProducersSection : public SyntheticSection {
diff --git a/lld/wasm/Writer.cpp b/lld/wasm/Writer.cpp
index 851a6d366210..dca6c260d429 100644
--- a/lld/wasm/Writer.cpp
+++ b/lld/wasm/Writer.cpp
@@ -1210,7 +1210,7 @@ void Writer::createSyntheticSections() {
   out.elemSec = make<ElemSection>();
   out.dataCountSec = make<DataCountSection>(segments);
   out.linkingSec = make<LinkingSection>(initFunctions, segments);
-  out.nameSec = make<NameSection>();
+  out.nameSec = make<NameSection>(segments);
   out.producersSec = make<ProducersSection>();
   out.targetFeaturesSec = make<TargetFeaturesSection>();
 }