diff --git a/llvm/lib/Target/BPF/BTF.h b/llvm/lib/Target/BPF/BTF.h
--- a/llvm/lib/Target/BPF/BTF.h
+++ b/llvm/lib/Target/BPF/BTF.h
@@ -180,8 +180,8 @@
 enum : uint8_t {
   VAR_STATIC = 0,           ///< Linkage: InternalLinkage
   VAR_GLOBAL_ALLOCATED = 1, ///< Linkage: ExternalLinkage
-  VAR_GLOBAL_TENTATIVE = 2, ///< Linkage: CommonLinkage
-  VAR_GLOBAL_EXTERNAL = 3,  ///< Linkage: ExternalLinkage
+  VAR_GLOBAL_EXTERNAL = 2,  ///< Linkage: ExternalLinkage
+  VAR_GLOBAL_TENTATIVE = 3, ///< Linkage: CommonLinkage
 };
 
 /// BTF_KIND_DATASEC are followed by multiple "struct BTFDataSecVar".
diff --git a/llvm/lib/Target/BPF/BTFDebug.cpp b/llvm/lib/Target/BPF/BTFDebug.cpp
--- a/llvm/lib/Target/BPF/BTFDebug.cpp
+++ b/llvm/lib/Target/BPF/BTFDebug.cpp
@@ -1055,20 +1055,40 @@
   // Collect all types referenced by globals.
   const Module *M = MMI->getModule();
   for (const GlobalVariable &Global : M->globals()) {
-    // Ignore external globals for now.
-    if (!Global.hasInitializer() && Global.hasExternalLinkage())
-      continue;
+    // Support all globals:
+    //   . static: VAR_STATIC, in DataSec.
+    //   . initialized global (0 or non-0): VAR_GLOBAL_ALLOCATED, in DataSec.
+    //   . external global: VAR_GLOBAL_EXTERNAL, not in DataSec.
+    //   . common global: VAR_GLOBAL_TENTATIVE, not in DataSec.
+    // Whether DataSec is readonly or not can be found from the
+    // corresponding ELF section flags.
 
     // Decide the section name.
+    // CommonLinkage variables do not have section names, and we
+    // don't want to put them into .bss/.data/.rodata sections.
     StringRef SecName;
-    if (Global.hasSection()) {
-      SecName = Global.getSection();
-    } else {
-      // data, bss, or readonly sections
-      if (Global.isConstant())
-        SecName = ".rodata";
+    uint32_t GVarInfo;
+    auto Linkage = Global.getLinkage();
+    if (Global.hasInitializer() && Linkage != GlobalValue::CommonLinkage) {
+      if (Global.hasSection()) {
+        SecName = Global.getSection();
+      } else {
+        // data, bss, or readonly sections
+        if (Global.isConstant())
+          SecName = ".rodata";
+        else
+          SecName = Global.getInitializer()->isZeroValue() ? ".bss" : ".data";
+      }
+      if (Linkage == GlobalValue::InternalLinkage)
+        GVarInfo = BTF::VAR_STATIC;
       else
-        SecName = Global.getInitializer()->isZeroValue() ? ".bss" : ".data";
+        GVarInfo = BTF::VAR_GLOBAL_ALLOCATED;
+    } else if (Linkage == GlobalValue::CommonLinkage) {
+      GVarInfo = BTF::VAR_GLOBAL_TENTATIVE;
+    } else {
+      // External variables.
+      GVarInfo = BTF::VAR_GLOBAL_EXTERNAL;
+      SecName = Global.getSection();
     }
 
     if (ProcessingMapDef != SecName.startswith(".maps"))
@@ -1085,27 +1105,13 @@
       break;
     }
 
-    // Only support the following globals:
-    //  . static variables
-    //  . non-static global variables with section attributes
-    // Essentially means:
-    //  . .bcc/.data/.rodata DataSec entities only contain static data
-    //  . Other DataSec entities contain static or initialized global data.
-    //    Initialized global data are mostly used for finding map key/value type
-    //    id's. Whether DataSec is readonly or not can be found from
-    //    corresponding ELF section flags.
-    auto Linkage = Global.getLinkage();
-    if (Linkage != GlobalValue::InternalLinkage &&
-        (Linkage != GlobalValue::ExternalLinkage || !Global.hasSection()))
-      continue;
-
-    uint32_t GVarInfo = Linkage == GlobalValue::ExternalLinkage
-                            ? BTF::VAR_GLOBAL_ALLOCATED
-                            : BTF::VAR_STATIC;
     auto VarEntry =
         std::make_unique<BTFKindVar>(Global.getName(), GVTypeId, GVarInfo);
     uint32_t VarId = addType(std::move(VarEntry));
 
+    if (SecName.empty())
+      continue;
+
     // Find or create a DataSec
     if (DataSecEntries.find(SecName) == DataSecEntries.end()) {
       DataSecEntries[SecName] = std::make_unique<BTFKindDataSec>(Asm, SecName);