[llvm] [llvm] Update call graph ELF section type. (PR #164461)
Prabhu Rajasekaran via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 22 09:49:22 PDT 2025
https://github.com/Prabhuk updated https://github.com/llvm/llvm-project/pull/164461
>From fd620a5f8cdde3448a02f01ce70a0fc8e976fa19 Mon Sep 17 00:00:00 2001
From: prabhukr <prabhukr at google.com>
Date: Tue, 21 Oct 2025 17:15:08 +0000
Subject: [PATCH 1/3] [llvm] Update call graph ELF section type.
Make call graph section to have a dedicated type instead of the generic
progbits type.
---
llvm/include/llvm/BinaryFormat/ELF.h | 1 +
llvm/lib/MC/MCAsmInfoELF.cpp | 2 ++
llvm/lib/MC/MCObjectFileInfo.cpp | 6 +++---
llvm/lib/MC/MCParser/ELFAsmParser.cpp | 2 ++
llvm/lib/Object/ELF.cpp | 1 +
llvm/test/CodeGen/ARM/call-graph-section-addrtaken.ll | 2 +-
llvm/test/CodeGen/ARM/call-graph-section-assembly.ll | 2 +-
llvm/test/CodeGen/X86/call-graph-section-addrtaken.ll | 2 +-
llvm/test/CodeGen/X86/call-graph-section-assembly.ll | 2 +-
9 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/llvm/include/llvm/BinaryFormat/ELF.h b/llvm/include/llvm/BinaryFormat/ELF.h
index 8d0dc64199ebf..73ae229fbc138 100644
--- a/llvm/include/llvm/BinaryFormat/ELF.h
+++ b/llvm/include/llvm/BinaryFormat/ELF.h
@@ -1185,6 +1185,7 @@ enum : unsigned {
SHT_LLVM_LTO = 0x6fff4c0c, // .llvm.lto for fat LTO.
SHT_LLVM_JT_SIZES = 0x6fff4c0d, // LLVM jump tables sizes.
SHT_LLVM_CFI_JUMP_TABLE = 0x6fff4c0e, // LLVM CFI jump table.
+ SHT_LLVM_CALL_GRAPH_SECTION = 0x6fff4c0f, // LLVM Call Graph Section.
// Android's experimental support for SHT_RELR sections.
// https://android.googlesource.com/platform/bionic/+/b7feec74547f84559a1467aca02708ff61346d2a/libc/include/elf.h#512
SHT_ANDROID_RELR = 0x6fffff00, // Relocation entries; only offsets.
diff --git a/llvm/lib/MC/MCAsmInfoELF.cpp b/llvm/lib/MC/MCAsmInfoELF.cpp
index 98090d34bcbdc..a97bdf42aa91c 100644
--- a/llvm/lib/MC/MCAsmInfoELF.cpp
+++ b/llvm/lib/MC/MCAsmInfoELF.cpp
@@ -197,6 +197,8 @@ void MCAsmInfoELF::printSwitchToSection(const MCSection &Section,
OS << "llvm_jt_sizes";
else if (Sec.Type == ELF::SHT_LLVM_CFI_JUMP_TABLE)
OS << "llvm_cfi_jump_table";
+ else if (Sec.Type == ELF::SHT_LLVM_CALL_GRAPH_SECTION)
+ OS << "llvm_call_graph_section";
else
OS << "0x" << Twine::utohexstr(Sec.Type);
diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index aee3c3b84fd4a..8ee28e86e0216 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -553,8 +553,8 @@ void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
SFrameSection =
Ctx->getELFSection(".sframe", ELF::SHT_GNU_SFRAME, ELF::SHF_ALLOC);
- CallGraphSection =
- Ctx->getELFSection(".llvm.callgraph", ELF::SHT_PROGBITS, 0);
+ CallGraphSection = Ctx->getELFSection(".llvm.callgraph",
+ ELF::SHT_LLVM_CALL_GRAPH_SECTION, 0);
StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
@@ -1172,7 +1172,7 @@ MCObjectFileInfo::getCallGraphSection(const MCSection &TextSec) const {
}
return Ctx->getELFSection(
- ".llvm.callgraph", ELF::SHT_PROGBITS, Flags, 0, GroupName,
+ ".llvm.callgraph", ELF::SHT_LLVM_CALL_GRAPH_SECTION, Flags, 0, GroupName,
/*IsComdat=*/true, ElfSec.getUniqueID(),
static_cast<const MCSymbolELF *>(TextSec.getBeginSymbol()));
}
diff --git a/llvm/lib/MC/MCParser/ELFAsmParser.cpp b/llvm/lib/MC/MCParser/ELFAsmParser.cpp
index 6195355626fd5..c19dffb7b4ad1 100644
--- a/llvm/lib/MC/MCParser/ELFAsmParser.cpp
+++ b/llvm/lib/MC/MCParser/ELFAsmParser.cpp
@@ -637,6 +637,8 @@ bool ELFAsmParser::parseSectionArguments(bool IsPush, SMLoc loc) {
Type = ELF::SHT_LLVM_JT_SIZES;
else if (TypeName == "llvm_cfi_jump_table")
Type = ELF::SHT_LLVM_CFI_JUMP_TABLE;
+ else if (TypeName == "llvm_call_graph_section")
+ Type = ELF::SHT_LLVM_CALL_GRAPH_SECTION;
else if (TypeName.getAsInteger(0, Type))
return TokError("unknown section type");
}
diff --git a/llvm/lib/Object/ELF.cpp b/llvm/lib/Object/ELF.cpp
index f256e7b56591b..55236ccc97202 100644
--- a/llvm/lib/Object/ELF.cpp
+++ b/llvm/lib/Object/ELF.cpp
@@ -322,6 +322,7 @@ StringRef llvm::object::getELFSectionTypeName(uint32_t Machine, unsigned Type) {
STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_LTO);
STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_JT_SIZES)
STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_CFI_JUMP_TABLE)
+ STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_CALL_GRAPH_SECTION);
STRINGIFY_ENUM_CASE(ELF, SHT_GNU_SFRAME);
STRINGIFY_ENUM_CASE(ELF, SHT_GNU_ATTRIBUTES);
STRINGIFY_ENUM_CASE(ELF, SHT_GNU_HASH);
diff --git a/llvm/test/CodeGen/ARM/call-graph-section-addrtaken.ll b/llvm/test/CodeGen/ARM/call-graph-section-addrtaken.ll
index 972a4708994db..7d0613f009e17 100644
--- a/llvm/test/CodeGen/ARM/call-graph-section-addrtaken.ll
+++ b/llvm/test/CodeGen/ARM/call-graph-section-addrtaken.ll
@@ -27,7 +27,7 @@ entry:
!1 = !{i64 0, !"_ZTSFivE.generalized"}
!2 = !{i64 0, !"_ZTSFviE.generalized"}
-; CHECK: .section .llvm.callgraph,"o",%progbits,.text
+; CHECK: .section .llvm.callgraph,"o",%llvm_call_graph_section,.text
;; Version
; CHECK-NEXT: .byte 0
;; Flags -- Potential indirect target so LSB is set to 1. Other bits are 0.
diff --git a/llvm/test/CodeGen/ARM/call-graph-section-assembly.ll b/llvm/test/CodeGen/ARM/call-graph-section-assembly.ll
index ec8d5b8ad94af..cc0201eaf06bb 100644
--- a/llvm/test/CodeGen/ARM/call-graph-section-assembly.ll
+++ b/llvm/test/CodeGen/ARM/call-graph-section-assembly.ll
@@ -36,7 +36,7 @@ entry:
!4 = !{!5}
!5 = !{i64 0, !"_ZTSFPvS_E.generalized"}
-; CHECK: .section .llvm.callgraph,"o",%progbits,.text
+; CHECK: .section .llvm.callgraph,"o",%llvm_call_graph_section,.text
;; Version
; CHECK-NEXT: .byte 0
;; Flags
diff --git a/llvm/test/CodeGen/X86/call-graph-section-addrtaken.ll b/llvm/test/CodeGen/X86/call-graph-section-addrtaken.ll
index 632d90d825d69..96c8e6c97c1f0 100644
--- a/llvm/test/CodeGen/X86/call-graph-section-addrtaken.ll
+++ b/llvm/test/CodeGen/X86/call-graph-section-addrtaken.ll
@@ -27,7 +27,7 @@ entry:
!1 = !{i64 0, !"_ZTSFivE.generalized"}
!2 = !{i64 0, !"_ZTSFviE.generalized"}
-; CHECK: .section .llvm.callgraph,"o", at progbits,.text
+; CHECK: .section .llvm.callgraph,"o", at llvm_call_graph_section,.text
;; Version
; CHECK-NEXT: .byte 0
;; Flags -- Potential indirect target so LSB is set to 1. Other bits are 0.
diff --git a/llvm/test/CodeGen/X86/call-graph-section-assembly.ll b/llvm/test/CodeGen/X86/call-graph-section-assembly.ll
index ed6849a4e452d..22b49d9f6a653 100644
--- a/llvm/test/CodeGen/X86/call-graph-section-assembly.ll
+++ b/llvm/test/CodeGen/X86/call-graph-section-assembly.ll
@@ -36,7 +36,7 @@ entry:
!4 = !{!5}
!5 = !{i64 0, !"_ZTSFPvS_E.generalized"}
-; CHECK: .section .llvm.callgraph,"o", at progbits,.text
+; CHECK: .section .llvm.callgraph,"o", at llvm_call_graph_section,.text
;; Version
; CHECK-NEXT: .byte 0
;; Flags
>From 81240cfd371fb17a9b9485bbb9b809b692445122 Mon Sep 17 00:00:00 2001
From: prabhukr <prabhukr at google.com>
Date: Tue, 21 Oct 2025 23:03:10 +0000
Subject: [PATCH 2/3] Rename type and add doc.
---
llvm/docs/Extensions.rst | 31 +++++++++++++++++++
llvm/include/llvm/BinaryFormat/ELF.h | 2 +-
llvm/lib/MC/MCAsmInfoELF.cpp | 4 +--
llvm/lib/MC/MCObjectFileInfo.cpp | 6 ++--
llvm/lib/MC/MCParser/ELFAsmParser.cpp | 4 +--
llvm/lib/Object/ELF.cpp | 2 +-
.../ARM/call-graph-section-addrtaken.ll | 2 +-
.../ARM/call-graph-section-assembly.ll | 2 +-
.../X86/call-graph-section-addrtaken.ll | 2 +-
.../X86/call-graph-section-assembly.ll | 2 +-
10 files changed, 44 insertions(+), 13 deletions(-)
diff --git a/llvm/docs/Extensions.rst b/llvm/docs/Extensions.rst
index 89a0e80fef5ef..e2b481e4f8997 100644
--- a/llvm/docs/Extensions.rst
+++ b/llvm/docs/Extensions.rst
@@ -601,6 +601,37 @@ sees fit (generally the section that would provide the best locality).
.. _CFI jump table: https://clang.llvm.org/docs/ControlFlowIntegrityDesign.html#forward-edge-cfi-for-indirect-function-calls
+``SHT_LLVM_CALL_GRAPH`` Section (Call Graph)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This section is used to store the call graph. It has a type of
+``SHT_LLVM_CALL_GRAPH`` (0x6fff4c0f). Details of call graph section layout
+are described in :doc:`CallGraphSection`.
+
+For example:
+
+.. code-block:: gas
+
+ .section ".llvm.callgraph","", at llvm_call_graph
+ .byte 0
+ .byte 7
+ .quad .Lball
+ .quad 0
+ .byte 3
+ .quad foo
+ .quad bar
+ .quad baz
+ .byte 3
+ .quad 4524972987496481828
+ .quad 3498816979441845844
+ .quad 8646233951371320954
+
+This indicates that ``ball`` calls ``foo``, ``bar`` and ``baz`` directly;
+``ball`` indirectly calls functions whose types are ``4524972987496481828``,
+``3498816979441845844`` and ``8646233951371320954``.
+
+
+
CodeView-Dependent
------------------
diff --git a/llvm/include/llvm/BinaryFormat/ELF.h b/llvm/include/llvm/BinaryFormat/ELF.h
index 73ae229fbc138..6ee6b666c1735 100644
--- a/llvm/include/llvm/BinaryFormat/ELF.h
+++ b/llvm/include/llvm/BinaryFormat/ELF.h
@@ -1185,7 +1185,7 @@ enum : unsigned {
SHT_LLVM_LTO = 0x6fff4c0c, // .llvm.lto for fat LTO.
SHT_LLVM_JT_SIZES = 0x6fff4c0d, // LLVM jump tables sizes.
SHT_LLVM_CFI_JUMP_TABLE = 0x6fff4c0e, // LLVM CFI jump table.
- SHT_LLVM_CALL_GRAPH_SECTION = 0x6fff4c0f, // LLVM Call Graph Section.
+ SHT_LLVM_CALL_GRAPH = 0x6fff4c0f, // LLVM Call Graph Section.
// Android's experimental support for SHT_RELR sections.
// https://android.googlesource.com/platform/bionic/+/b7feec74547f84559a1467aca02708ff61346d2a/libc/include/elf.h#512
SHT_ANDROID_RELR = 0x6fffff00, // Relocation entries; only offsets.
diff --git a/llvm/lib/MC/MCAsmInfoELF.cpp b/llvm/lib/MC/MCAsmInfoELF.cpp
index a97bdf42aa91c..6670971c3c6ed 100644
--- a/llvm/lib/MC/MCAsmInfoELF.cpp
+++ b/llvm/lib/MC/MCAsmInfoELF.cpp
@@ -197,8 +197,8 @@ void MCAsmInfoELF::printSwitchToSection(const MCSection &Section,
OS << "llvm_jt_sizes";
else if (Sec.Type == ELF::SHT_LLVM_CFI_JUMP_TABLE)
OS << "llvm_cfi_jump_table";
- else if (Sec.Type == ELF::SHT_LLVM_CALL_GRAPH_SECTION)
- OS << "llvm_call_graph_section";
+ else if (Sec.Type == ELF::SHT_LLVM_CALL_GRAPH)
+ OS << "llvm_call_graph";
else
OS << "0x" << Twine::utohexstr(Sec.Type);
diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index 8ee28e86e0216..b2f500083f5d8 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -553,8 +553,8 @@ void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
SFrameSection =
Ctx->getELFSection(".sframe", ELF::SHT_GNU_SFRAME, ELF::SHF_ALLOC);
- CallGraphSection = Ctx->getELFSection(".llvm.callgraph",
- ELF::SHT_LLVM_CALL_GRAPH_SECTION, 0);
+ CallGraphSection =
+ Ctx->getELFSection(".llvm.callgraph", ELF::SHT_LLVM_CALL_GRAPH, 0);
StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
@@ -1172,7 +1172,7 @@ MCObjectFileInfo::getCallGraphSection(const MCSection &TextSec) const {
}
return Ctx->getELFSection(
- ".llvm.callgraph", ELF::SHT_LLVM_CALL_GRAPH_SECTION, Flags, 0, GroupName,
+ ".llvm.callgraph", ELF::SHT_LLVM_CALL_GRAPH, Flags, 0, GroupName,
/*IsComdat=*/true, ElfSec.getUniqueID(),
static_cast<const MCSymbolELF *>(TextSec.getBeginSymbol()));
}
diff --git a/llvm/lib/MC/MCParser/ELFAsmParser.cpp b/llvm/lib/MC/MCParser/ELFAsmParser.cpp
index c19dffb7b4ad1..1a3752f71f065 100644
--- a/llvm/lib/MC/MCParser/ELFAsmParser.cpp
+++ b/llvm/lib/MC/MCParser/ELFAsmParser.cpp
@@ -637,8 +637,8 @@ bool ELFAsmParser::parseSectionArguments(bool IsPush, SMLoc loc) {
Type = ELF::SHT_LLVM_JT_SIZES;
else if (TypeName == "llvm_cfi_jump_table")
Type = ELF::SHT_LLVM_CFI_JUMP_TABLE;
- else if (TypeName == "llvm_call_graph_section")
- Type = ELF::SHT_LLVM_CALL_GRAPH_SECTION;
+ else if (TypeName == "llvm_call_graph")
+ Type = ELF::SHT_LLVM_CALL_GRAPH;
else if (TypeName.getAsInteger(0, Type))
return TokError("unknown section type");
}
diff --git a/llvm/lib/Object/ELF.cpp b/llvm/lib/Object/ELF.cpp
index 55236ccc97202..6da97f9b3755d 100644
--- a/llvm/lib/Object/ELF.cpp
+++ b/llvm/lib/Object/ELF.cpp
@@ -322,7 +322,7 @@ StringRef llvm::object::getELFSectionTypeName(uint32_t Machine, unsigned Type) {
STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_LTO);
STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_JT_SIZES)
STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_CFI_JUMP_TABLE)
- STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_CALL_GRAPH_SECTION);
+ STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_CALL_GRAPH);
STRINGIFY_ENUM_CASE(ELF, SHT_GNU_SFRAME);
STRINGIFY_ENUM_CASE(ELF, SHT_GNU_ATTRIBUTES);
STRINGIFY_ENUM_CASE(ELF, SHT_GNU_HASH);
diff --git a/llvm/test/CodeGen/ARM/call-graph-section-addrtaken.ll b/llvm/test/CodeGen/ARM/call-graph-section-addrtaken.ll
index 7d0613f009e17..cabd43edff9d6 100644
--- a/llvm/test/CodeGen/ARM/call-graph-section-addrtaken.ll
+++ b/llvm/test/CodeGen/ARM/call-graph-section-addrtaken.ll
@@ -27,7 +27,7 @@ entry:
!1 = !{i64 0, !"_ZTSFivE.generalized"}
!2 = !{i64 0, !"_ZTSFviE.generalized"}
-; CHECK: .section .llvm.callgraph,"o",%llvm_call_graph_section,.text
+; CHECK: .section .llvm.callgraph,"o",%llvm_call_graph,.text
;; Version
; CHECK-NEXT: .byte 0
;; Flags -- Potential indirect target so LSB is set to 1. Other bits are 0.
diff --git a/llvm/test/CodeGen/ARM/call-graph-section-assembly.ll b/llvm/test/CodeGen/ARM/call-graph-section-assembly.ll
index cc0201eaf06bb..3d3974ee6ba3b 100644
--- a/llvm/test/CodeGen/ARM/call-graph-section-assembly.ll
+++ b/llvm/test/CodeGen/ARM/call-graph-section-assembly.ll
@@ -36,7 +36,7 @@ entry:
!4 = !{!5}
!5 = !{i64 0, !"_ZTSFPvS_E.generalized"}
-; CHECK: .section .llvm.callgraph,"o",%llvm_call_graph_section,.text
+; CHECK: .section .llvm.callgraph,"o",%llvm_call_graph,.text
;; Version
; CHECK-NEXT: .byte 0
;; Flags
diff --git a/llvm/test/CodeGen/X86/call-graph-section-addrtaken.ll b/llvm/test/CodeGen/X86/call-graph-section-addrtaken.ll
index 96c8e6c97c1f0..f36baba402421 100644
--- a/llvm/test/CodeGen/X86/call-graph-section-addrtaken.ll
+++ b/llvm/test/CodeGen/X86/call-graph-section-addrtaken.ll
@@ -27,7 +27,7 @@ entry:
!1 = !{i64 0, !"_ZTSFivE.generalized"}
!2 = !{i64 0, !"_ZTSFviE.generalized"}
-; CHECK: .section .llvm.callgraph,"o", at llvm_call_graph_section,.text
+; CHECK: .section .llvm.callgraph,"o", at llvm_call_graph,.text
;; Version
; CHECK-NEXT: .byte 0
;; Flags -- Potential indirect target so LSB is set to 1. Other bits are 0.
diff --git a/llvm/test/CodeGen/X86/call-graph-section-assembly.ll b/llvm/test/CodeGen/X86/call-graph-section-assembly.ll
index 22b49d9f6a653..cdbad668aec54 100644
--- a/llvm/test/CodeGen/X86/call-graph-section-assembly.ll
+++ b/llvm/test/CodeGen/X86/call-graph-section-assembly.ll
@@ -36,7 +36,7 @@ entry:
!4 = !{!5}
!5 = !{i64 0, !"_ZTSFPvS_E.generalized"}
-; CHECK: .section .llvm.callgraph,"o", at llvm_call_graph_section,.text
+; CHECK: .section .llvm.callgraph,"o", at llvm_call_graph,.text
;; Version
; CHECK-NEXT: .byte 0
;; Flags
>From 7c2b6e8f9e346f6925e61ee604a5be1822adf867 Mon Sep 17 00:00:00 2001
From: prabhukr <prabhukr at google.com>
Date: Wed, 22 Oct 2025 09:48:51 -0700
Subject: [PATCH 3/3] Remove unnecessary empty lines from doc.
---
llvm/docs/Extensions.rst | 2 --
1 file changed, 2 deletions(-)
diff --git a/llvm/docs/Extensions.rst b/llvm/docs/Extensions.rst
index e2b481e4f8997..24959a6a70b6a 100644
--- a/llvm/docs/Extensions.rst
+++ b/llvm/docs/Extensions.rst
@@ -630,8 +630,6 @@ This indicates that ``ball`` calls ``foo``, ``bar`` and ``baz`` directly;
``ball`` indirectly calls functions whose types are ``4524972987496481828``,
``3498816979441845844`` and ``8646233951371320954``.
-
-
CodeView-Dependent
------------------
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