[llvm-branch-commits] [RISCV][lld] Support merging RISC-V Atomics ABI attributes (PR #97347)
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Mon Jul 1 13:55:44 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lld
@llvm/pr-subscribers-lld-elf
Author: Paul Kirth (ilovepi)
<details>
<summary>Changes</summary>
This patch adds support for merging the atomic_abi attribute, specifid in
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc#tag_riscv_atomic_abi-14-uleb128version,
to LLD.
The atomics_abi tag merging is conducted as follows:
UNKNOWN is safe to merge with all other values.
A6C is compatible with A6S, and results in the A6C ABI.
A6C is incompatible with A7, and results in an error.
A6S and A7 are compatible, and merging results in the A7 ABI.
Note: the A7 is not yet supported in either LLVM or in any current hardware,
and is therefore omitted from attribute generation in RISCVTargetStreamer.
LLD support was split from https://github.com/llvm/llvm-project/pull/90266
---
Full diff: https://github.com/llvm/llvm-project/pull/97347.diff
2 Files Affected:
- (modified) lld/ELF/Arch/RISCV.cpp (+78)
- (modified) lld/test/ELF/riscv-attributes.s (+203)
``````````diff
diff --git a/lld/ELF/Arch/RISCV.cpp b/lld/ELF/Arch/RISCV.cpp
index e4d63250135e0..aa11aaa61a532 100644
--- a/lld/ELF/Arch/RISCV.cpp
+++ b/lld/ELF/Arch/RISCV.cpp
@@ -1084,10 +1084,76 @@ static void mergeArch(RISCVISAUtils::OrderedExtensionMap &mergedExts,
}
}
+static void mergeAtomic(DenseMap<unsigned, unsigned>::iterator it,
+ const InputSectionBase *oldSection,
+ const InputSectionBase *newSection,
+ RISCVAttrs::RISCVAtomicAbiTag oldTag,
+ RISCVAttrs::RISCVAtomicAbiTag newTag) {
+ using RISCVAttrs::RISCVAtomicAbiTag;
+ // Same tags stay the same, and UNKNOWN is compatible with anything
+ if (oldTag == newTag || newTag == RISCVAtomicAbiTag::UNKNOWN)
+ return;
+
+ auto reportAbiError = [&]() {
+ errorOrWarn("atomic abi mismatch for " + oldSection->name + "\n>>> " +
+ toString(oldSection) +
+ ": atomic_abi=" + Twine(static_cast<unsigned>(oldTag)) +
+ "\n>>> " + toString(newSection) +
+ ": atomic_abi=" + Twine(static_cast<unsigned>(newTag)));
+ };
+
+ switch (static_cast<RISCVAtomicAbiTag>(oldTag)) {
+ case RISCVAtomicAbiTag::UNKNOWN:
+ it->getSecond() = static_cast<unsigned>(newTag);
+ return;
+ case RISCVAtomicAbiTag::A6C:
+ switch (newTag) {
+ case RISCVAtomicAbiTag::A6S:
+ it->getSecond() = static_cast<unsigned>(RISCVAtomicAbiTag::A6C);
+ return;
+ case RISCVAtomicAbiTag::A7:
+ reportAbiError();
+ return;
+ case RISCVAttrs::RISCVAtomicAbiTag::UNKNOWN:
+ case RISCVAttrs::RISCVAtomicAbiTag::A6C:
+ return;
+ };
+
+ case RISCVAtomicAbiTag::A6S:
+ switch (newTag) {
+ case RISCVAtomicAbiTag::A6C:
+ it->getSecond() = static_cast<unsigned>(RISCVAtomicAbiTag::A6C);
+ return;
+ case RISCVAtomicAbiTag::A7:
+ it->getSecond() = static_cast<unsigned>(RISCVAtomicAbiTag::A7);
+ return;
+ case RISCVAttrs::RISCVAtomicAbiTag::UNKNOWN:
+ case RISCVAttrs::RISCVAtomicAbiTag::A6S:
+ return;
+ };
+
+ case RISCVAtomicAbiTag::A7:
+ switch (newTag) {
+ case RISCVAtomicAbiTag::A6S:
+ it->getSecond() = static_cast<unsigned>(RISCVAtomicAbiTag::A7);
+ return;
+ case RISCVAtomicAbiTag::A6C:
+ reportAbiError();
+ return;
+ case RISCVAttrs::RISCVAtomicAbiTag::UNKNOWN:
+ case RISCVAttrs::RISCVAtomicAbiTag::A7:
+ return;
+ };
+ };
+ llvm_unreachable("unknown AtomicABI");
+}
+
static RISCVAttributesSection *
mergeAttributesSection(const SmallVector<InputSectionBase *, 0> §ions) {
+ using RISCVAttrs::RISCVAtomicAbiTag;
RISCVISAUtils::OrderedExtensionMap exts;
const InputSectionBase *firstStackAlign = nullptr;
+ const InputSectionBase *firstAtomicAbi = nullptr;
unsigned firstStackAlignValue = 0, xlen = 0;
bool hasArch = false;
@@ -1134,6 +1200,18 @@ mergeAttributesSection(const SmallVector<InputSectionBase *, 0> §ions) {
case RISCVAttrs::PRIV_SPEC_MINOR:
case RISCVAttrs::PRIV_SPEC_REVISION:
break;
+
+ case llvm::RISCVAttrs::AttrType::ATOMIC_ABI:
+ if (auto i = parser.getAttributeValue(tag.attr)) {
+ auto r = merged.intAttr.try_emplace(tag.attr, *i);
+ if (r.second)
+ firstAtomicAbi = sec;
+ else
+ mergeAtomic(r.first, firstAtomicAbi, sec,
+ static_cast<RISCVAtomicAbiTag>(r.first->getSecond()),
+ static_cast<RISCVAtomicAbiTag>(*i));
+ }
+ continue;
}
// Fallback for deprecated priv_spec* and other unknown attributes: retain
diff --git a/lld/test/ELF/riscv-attributes.s b/lld/test/ELF/riscv-attributes.s
index 68534d0fb6b75..38b0fe8e7797e 100644
--- a/lld/test/ELF/riscv-attributes.s
+++ b/lld/test/ELF/riscv-attributes.s
@@ -44,6 +44,40 @@
# RUN: not ld.lld a.o b.o c.o diff_stack_align.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=STACK_ALIGN --implicit-check-not=error:
# STACK_ALIGN: error: diff_stack_align.o:(.riscv.attributes) has stack_align=32 but a.o:(.riscv.attributes) has stack_align=16
+## RISC-V tag merging for atomic_abi values A6C and A7 lead to an error.
+# RUN: llvm-mc -filetype=obj -triple=riscv64 atomic_abi_A6C.s -o atomic_abi_A6C.o
+# RUN: llvm-mc -filetype=obj -triple=riscv64 atomic_abi_A7.s -o atomic_abi_A7.o
+# RUN: not ld.lld atomic_abi_A6C.o atomic_abi_A7.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=ATOMIC_ABI_ERROR --implicit-check-not=error:
+# ATOMIC_ABI_ERROR: error: atomic abi mismatch for .riscv.attributes
+# ATOMIC_ABI_ERROR-NEXT: >>> atomic_abi_A6C.o:(.riscv.attributes): atomic_abi=1
+# ATOMIC_ABI_ERROR-NEXT: >>> atomic_abi_A7.o:(.riscv.attributes): atomic_abi=3
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64 atomic_abi_A6S.s -o atomic_abi_A6S.o
+# RUN: ld.lld atomic_abi_A6S.o atomic_abi_A6C.o -o atomic_abi_A6C_A6S
+# RUN: llvm-readobj -A atomic_abi_A6C_A6S | FileCheck %s --check-prefix=A6C_A6S
+
+# RUN: ld.lld atomic_abi_A6S.o atomic_abi_A7.o -o atomic_abi_A6S_A7
+# RUN: llvm-readobj -A atomic_abi_A6S_A7 | FileCheck %s --check-prefix=A6S_A7
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64 atomic_abi_unknown.s -o atomic_abi_unknown.o
+# RUN: ld.lld atomic_abi_unknown.o atomic_abi_A6C.o -o atomic_abi_A6C_unknown
+# RUN: llvm-readobj -A atomic_abi_A6C_unknown | FileCheck %s --check-prefixes=UNKNOWN_A6C
+
+# RUN: ld.lld atomic_abi_unknown.o diff_stack_align.o -o atomic_abi_none_unknown
+# RUN: llvm-readobj -A atomic_abi_none_unknown | FileCheck %s --check-prefixes=UNKNOWN_NONE
+
+# RUN: ld.lld diff_stack_align.o atomic_abi_A6C.o -o atomic_abi_A6C_none
+# RUN: llvm-readobj -A atomic_abi_A6C_none | FileCheck %s --check-prefixes=NONE_A6C
+
+# RUN: ld.lld atomic_abi_unknown.o atomic_abi_A6S.o -o atomic_abi_A6S_unknown
+# RUN: llvm-readobj -A atomic_abi_A6S_unknown | FileCheck %s --check-prefix=UNKNOWN_A6S
+
+# RUN: ld.lld atomic_abi_unknown.o atomic_abi_A7.o -o atomic_abi_A7_unknown
+# RUN: llvm-readobj -A atomic_abi_A7_unknown | FileCheck %s --check-prefix=UNKNOWN_A7
+
+# RUN: ld.lld diff_stack_align.o atomic_abi_A7.o -o atomic_abi_A7_none
+# RUN: llvm-readobj -A atomic_abi_A7_none | FileCheck %s --check-prefix=NONE_A7
+
## The deprecated priv_spec is not handled as GNU ld does.
## Differing priv_spec attributes lead to an absent attribute.
# RUN: llvm-mc -filetype=obj -triple=riscv64 diff_priv_spec.s -o diff_priv_spec.o
@@ -286,6 +320,175 @@
.attribute priv_spec, 3
.attribute priv_spec_minor, 3
+#--- atomic_abi_unknown.s
+.attribute atomic_abi, 0
+
+#--- atomic_abi_A6C.s
+.attribute atomic_abi, 1
+
+#--- atomic_abi_A6S.s
+.attribute atomic_abi, 2
+
+#--- atomic_abi_A7.s
+.attribute atomic_abi, 3
+
+# UNKNOWN_NONE: BuildAttributes {
+# UNKNOWN_NONE-NEXT: FormatVersion: 0x41
+# UNKNOWN_NONE-NEXT: Section 1 {
+# UNKNOWN_NONE-NEXT: SectionLength: 17
+# UNKNOWN_NONE-NEXT: Vendor: riscv
+# UNKNOWN_NONE-NEXT: Tag: Tag_File (0x1)
+# UNKNOWN_NONE-NEXT: Size: 7
+# UNKNOWN_NONE-NEXT: FileAttributes {
+# UNKNOWN_NONE-NEXT: Attribute {
+# UNKNOWN_NONE-NEXT: Tag: 4
+# UNKNOWN_NONE-NEXT: Value: 32
+# UNKNOWN_NONE-NEXT: TagName: stack_align
+# UNKNOWN_NONE-NEXT: Description: Stack alignment is 32-bytes
+# UNKNOWN_NONE-NEXT: }
+# UNKNOWN_NONE-NEXT: }
+# UNKNOWN_NONE-NEXT: }
+# UNKNOWN_NONE-NEXT: }
+
+# NONE_A6C: BuildAttributes {
+# NONE_A6C-NEXT: FormatVersion: 0x41
+# NONE_A6C-NEXT: Section 1 {
+# NONE_A6C-NEXT: SectionLength: 19
+# NONE_A6C-NEXT: Vendor: riscv
+# NONE_A6C-NEXT: Tag: Tag_File (0x1)
+# NONE_A6C-NEXT: Size: 9
+# NONE_A6C-NEXT: FileAttributes {
+# NONE_A6C-NEXT: Attribute {
+# NONE_A6C-NEXT: Tag: 14
+# NONE_A6C-NEXT: Value: 1
+# NONE_A6C-NEXT: TagName: atomic_abi
+# NONE_A6C-NEXT: Description: Atomic ABI is 1
+# NONE_A6C-NEXT: }
+# NONE_A6C-NEXT: Attribute {
+# NONE_A6C-NEXT: Tag: 4
+# NONE_A6C-NEXT: Value: 32
+# NONE_A6C-NEXT: TagName: stack_align
+# NONE_A6C-NEXT: Description: Stack alignment is 32-bytes
+# NONE_A6C-NEXT: }
+# NONE_A6C-NEXT: }
+# NONE_A6C-NEXT: }
+# NONE_A6C-NEXT: }
+
+# UNKNOWN_A6C: BuildAttributes {
+# UNKNOWN_A6C-NEXT: FormatVersion: 0x41
+# UNKNOWN_A6C-NEXT: Section 1 {
+# UNKNOWN_A6C-NEXT: SectionLength: 17
+# UNKNOWN_A6C-NEXT: Vendor: riscv
+# UNKNOWN_A6C-NEXT: Tag: Tag_File (0x1)
+# UNKNOWN_A6C-NEXT: Size: 7
+# UNKNOWN_A6C-NEXT: FileAttributes {
+# UNKNOWN_A6C-NEXT: Attribute {
+# UNKNOWN_A6C-NEXT: Tag: 14
+# UNKNOWN_A6C-NEXT: Value: 1
+# UNKNOWN_A6C-NEXT: TagName: atomic_abi
+# UNKNOWN_A6C-NEXT: Description: Atomic ABI is 1
+# UNKNOWN_A6C-NEXT: }
+# UNKNOWN_A6C-NEXT: }
+# UNKNOWN_A6C-NEXT: }
+# UNKNOWN_A6C-NEXT: }
+
+# UNKNOWN_A6S: BuildAttributes {
+# UNKNOWN_A6S-NEXT: FormatVersion: 0x41
+# UNKNOWN_A6S-NEXT: Section 1 {
+# UNKNOWN_A6S-NEXT: SectionLength:
+# UNKNOWN_A6S-NEXT: Vendor: riscv
+# UNKNOWN_A6S-NEXT: Tag: Tag_File (0x1)
+# UNKNOWN_A6S-NEXT: Size: 7
+# UNKNOWN_A6S-NEXT: FileAttributes {
+# UNKNOWN_A6S-NEXT: Attribute {
+# UNKNOWN_A6S-NEXT: Tag: 14
+# UNKNOWN_A6S-NEXT: Value: 2
+# UNKNOWN_A6S-NEXT: TagName: atomic_abi
+# UNKNOWN_A6S-NEXT: Description: Atomic ABI is 2
+# UNKNOWN_A6S-NEXT: }
+# UNKNOWN_A6S-NEXT: }
+# UNKNOWN_A6S-NEXT: }
+# UNKNOWN_A6S-NEXT: }
+
+# NONE_A7: BuildAttributes {
+# NONE_A7-NEXT: FormatVersion: 0x41
+# NONE_A7-NEXT: Section 1 {
+# NONE_A7-NEXT: SectionLength: 19
+# NONE_A7-NEXT: Vendor: riscv
+# NONE_A7-NEXT: Tag: Tag_File (0x1)
+# NONE_A7-NEXT: Size: 9
+# NONE_A7-NEXT: FileAttributes {
+# NONE_A7-NEXT: Attribute {
+# NONE_A7-NEXT: Tag: 14
+# NONE_A7-NEXT: Value: 3
+# NONE_A7-NEXT: TagName: atomic_abi
+# NONE_A7-NEXT: Description: Atomic ABI is 3
+# NONE_A7-NEXT: }
+# NONE_A7-NEXT: Attribute {
+# NONE_A7-NEXT: Tag: 4
+# NONE_A7-NEXT: Value: 32
+# NONE_A7-NEXT: TagName: stack_align
+# NONE_A7-NEXT: Description: Stack alignment is 32-bytes
+# NONE_A7-NEXT: }
+# NONE_A7-NEXT: }
+# NONE_A7-NEXT: }
+# NONE_A7-NEXT: }
+
+
+# UNKNOWN_A7: BuildAttributes {
+# UNKNOWN_A7-NEXT: FormatVersion: 0x41
+# UNKNOWN_A7-NEXT: Section 1 {
+# UNKNOWN_A7-NEXT: SectionLength: 17
+# UNKNOWN_A7-NEXT: Vendor: riscv
+# UNKNOWN_A7-NEXT: Tag: Tag_File (0x1)
+# UNKNOWN_A7-NEXT: Size: 7
+# UNKNOWN_A7-NEXT: FileAttributes {
+# UNKNOWN_A7-NEXT: Attribute {
+# UNKNOWN_A7-NEXT: Tag: 14
+# UNKNOWN_A7-NEXT: Value: 3
+# UNKNOWN_A7-NEXT: TagName: atomic_abi
+# UNKNOWN_A7-NEXT: Description: Atomic ABI is 3
+# UNKNOWN_A7-NEXT: }
+# UNKNOWN_A7-NEXT: }
+# UNKNOWN_A7-NEXT: }
+# UNKNOWN_A7-NEXT: }
+
+# A6C_A6S: BuildAttributes {
+# A6C_A6S-NEXT: FormatVersion: 0x41
+# A6C_A6S-NEXT: Section 1 {
+# A6C_A6S-NEXT: SectionLength: 17
+# A6C_A6S-NEXT: Vendor: riscv
+# A6C_A6S-NEXT: Tag: Tag_File (0x1)
+# A6C_A6S-NEXT: Size: 7
+# A6C_A6S-NEXT: FileAttributes {
+# A6C_A6S-NEXT: Attribute {
+# A6C_A6S-NEXT: Tag: 14
+# A6C_A6S-NEXT: Value: 1
+# A6C_A6S-NEXT: TagName: atomic_abi
+# A6C_A6S-NEXT: Description: Atomic ABI is 1
+# A6C_A6S-NEXT: }
+# A6C_A6S-NEXT: }
+# A6C_A6S-NEXT: }
+# A6C_A6S-NEXT: }
+
+# A6S_A7: BuildAttributes {
+# A6S_A7-NEXT: FormatVersion: 0x41
+# A6S_A7-NEXT: Section 1 {
+# A6S_A7-NEXT: SectionLength: 17
+# A6S_A7-NEXT: Vendor: riscv
+# A6S_A7-NEXT: Tag: Tag_File (0x1)
+# A6S_A7-NEXT: Size: 7
+# A6S_A7-NEXT: FileAttributes {
+# A6S_A7-NEXT: Attribute {
+# A6S_A7-NEXT: Tag: 14
+# A6S_A7-NEXT: Value: 3
+# A6S_A7-NEXT: TagName: atomic_abi
+# A6S_A7-NEXT: Description: Atomic ABI is 3
+# A6S_A7-NEXT: }
+# A6S_A7-NEXT: }
+# A6S_A7-NEXT: }
+# A6S_A7-NEXT: }
+
#--- unknown13.s
.attribute 13, "0"
#--- unknown13a.s
``````````
</details>
https://github.com/llvm/llvm-project/pull/97347
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