Fix macro expansion for AMDHSA_BITS_SET

[JanekvO]

Corrects the AMDHSA_BITS_SET macro.

The VAL argument for the AMDHSA_BITS_SET macro is not encapsulated which may result in unintended expansion. An example of this can be observed in

llvm-project/llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.cpp

Lines 1242 to 1244 in f804217

	AMDHSA_BITS_SET(KD.kernel_code_properties,
	amdhsa::KERNEL_CODE_PROPERTY_ENABLE_WAVEFRONT_SIZE32,
	STI->getFeatureBits().test(FeatureWavefrontSize32) ? 1 : 0);

where the macro expands into

KD.kernel_code_properties &= ~amdhsa::KERNEL_CODE_PROPERTY_ENABLE_WAVEFRONT_SIZE32;
KD.kernel_code_properties |= ((STI->getFeatureBits().test(FeatureWavefrontSize32) ? 1 : 0 << amdhsa::KERNEL_CODE_PROPERTY_ENABLE_WAVEFRONT_SIZE32_SHIFT) & amdhsa::KERNEL_CODE_PROPERTY_ENABLE_WAVEFRONT_SIZE32)

[llvmbot]

@llvm/pr-subscribers-mc
@llvm/pr-subscribers-llvm-support

@llvm/pr-subscribers-backend-amdgpu

Author: Janek van Oirschot (JanekvO)

Changes

Corrects the AMDHSA_BITS_SET macro.

The VAL argument for the AMDHSA_BITS_SET macro is not encapsulated which may result in unintended expansion. An example of this can be observed in

llvm-project/llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.cpp

Lines 1242 to 1244 in f804217

	AMDHSA_BITS_SET(KD.kernel_code_properties,
	amdhsa::KERNEL_CODE_PROPERTY_ENABLE_WAVEFRONT_SIZE32,
	STI->getFeatureBits().test(FeatureWavefrontSize32) ? 1 : 0);

where the macro expands into

KD.kernel_code_properties &= ~amdhsa::KERNEL_CODE_PROPERTY_ENABLE_WAVEFRONT_SIZE32;
KD.kernel_code_properties |= ((STI->getFeatureBits().test(FeatureWavefrontSize32) ? 1 : 0 << amdhsa::KERNEL_CODE_PROPERTY_ENABLE_WAVEFRONT_SIZE32_SHIFT) & amdhsa::KERNEL_CODE_PROPERTY_ENABLE_WAVEFRONT_SIZE32)

---

Full diff: https://github.com/llvm/llvm-project/pull/85661.diff

2 Files Affected:

• (modified) llvm/include/llvm/Support/AMDHSAKernelDescriptor.h (+6-3)
• (modified) llvm/test/MC/AMDGPU/hsa-gfx12-v4.s (+3-3)

diff --git a/llvm/include/llvm/Support/AMDHSAKernelDescriptor.h b/llvm/include/llvm/Support/AMDHSAKernelDescriptor.h
index 84cac3ef700e05..a119b0724d677f 100644
--- a/llvm/include/llvm/Support/AMDHSAKernelDescriptor.h
+++ b/llvm/include/llvm/Support/AMDHSAKernelDescriptor.h
@@ -46,9 +46,12 @@
 
 // Sets bits for specified bit mask in specified destination.
 #ifndef AMDHSA_BITS_SET
-#define AMDHSA_BITS_SET(DST, MSK, VAL)  \
-  DST &= ~MSK;                          \
-  DST |= ((VAL << MSK ## _SHIFT) & MSK)
+#define AMDHSA_BITS_SET(DST, MSK, VAL)                                         \
+  do {                                                                         \
+    auto local = VAL;                                                          \
+    DST &= ~MSK;                                                               \
+    DST |= ((local << MSK##_SHIFT) & MSK);                                     \
+  } while (0)
 #endif // AMDHSA_BITS_SET
 
 namespace llvm {
diff --git a/llvm/test/MC/AMDGPU/hsa-gfx12-v4.s b/llvm/test/MC/AMDGPU/hsa-gfx12-v4.s
index 8b90e20bb87d1f..7b591904e877fd 100644
--- a/llvm/test/MC/AMDGPU/hsa-gfx12-v4.s
+++ b/llvm/test/MC/AMDGPU/hsa-gfx12-v4.s
@@ -29,7 +29,7 @@
 // OBJDUMP-NEXT: 0000 00000000 00000000 00000000 00000000
 // OBJDUMP-NEXT: 0010 00000000 00000000 00000000 00000000
 // OBJDUMP-NEXT: 0020 00000000 00000000 00000000 00000000
-// OBJDUMP-NEXT: 0030 00000c60 80000000 00000000 00000000
+// OBJDUMP-NEXT: 0030 00000c60 80000000 00040000 00000000
 // complete
 // OBJDUMP-NEXT: 0040 01000000 01000000 08000000 00000000
 // OBJDUMP-NEXT: 0050 00000000 00000000 00000000 00000000
@@ -39,12 +39,12 @@
 // OBJDUMP-NEXT: 0080 00000000 00000000 00000000 00000000
 // OBJDUMP-NEXT: 0090 00000000 00000000 00000000 00000000
 // OBJDUMP-NEXT: 00a0 00000000 00000000 00000000 00000000
-// OBJDUMP-NEXT: 00b0 00000060 80000000 00000000 00000000
+// OBJDUMP-NEXT: 00b0 00000060 80000000 00040000 00000000
 // disabled_user_sgpr
 // OBJDUMP-NEXT: 00c0 00000000 00000000 00000000 00000000
 // OBJDUMP-NEXT: 00d0 00000000 00000000 00000000 00000000
 // OBJDUMP-NEXT: 00e0 00000000 00000000 00000000 00000000
-// OBJDUMP-NEXT: 00f0 00000c60 80000000 00000000 00000000
+// OBJDUMP-NEXT: 00f0 00000c60 80000000 00040000 00000000
 
 .text
 // ASM: .text