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GH-115802: Remove no-plt for Linux targets #148238

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GH-115802: Remove no-plt for Linux targets #148238

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GH-115802: Remove no-plt for Linux targets
diegorusso Mar 25, 2026
89e4994
📜🤖 Added by blurb_it.
blurb-it[bot] Apr 8, 2026
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1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2026-04-08-06-59-23.gh-issue-115802.jqfZty.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Improve JIT code generation on Linux targets by reducing the indirect call to external symbols. Patch by Diego Russo.
15 changes: 11 additions & 4 deletions Python/jit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -316,18 +316,25 @@ patch_32(unsigned char *location, uint64_t value)
memcpy(location, &final_value, sizeof(final_value));
}

// 32-bit relative address.
// 32-bit absolute address, sign-extended by the instruction.
void
patch_32r(unsigned char *location, uint64_t value)
patch_32s(unsigned char *location, uint64_t value)
{
value -= (uintptr_t)location;
// Check that we're not out of range of 32 signed bits:
assert((int64_t)value >= -(1LL << 31));
assert((int64_t)value < (1LL << 31));
uint32_t final_value = (uint32_t)value;
int32_t final_value = (int32_t)value;
memcpy(location, &final_value, sizeof(final_value));
}

// 32-bit relative address.
void
patch_32r(unsigned char *location, uint64_t value)
{
value -= (uintptr_t)location;
patch_32s(location, value);
}

// 64-bit absolute address.
void
patch_64(unsigned char *location, uint64_t value)
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1 change: 1 addition & 0 deletions Tools/jit/_stencils.py
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Expand Up @@ -90,6 +90,7 @@ class HoleValue(enum.Enum):
"R_AARCH64_MOVW_UABS_G2_NC": "patch_aarch64_16c",
"R_AARCH64_MOVW_UABS_G3": "patch_aarch64_16d",
# x86_64-unknown-linux-gnu:
"R_X86_64_32S": "patch_32s",
"R_X86_64_64": "patch_64",
"R_X86_64_GOTPCRELX": "patch_x86_64_32rx",
"R_X86_64_PLT32": "patch_32r",
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4 changes: 2 additions & 2 deletions Tools/jit/_targets.py
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Expand Up @@ -594,7 +594,7 @@ def get_target(host: str) -> _COFF32 | _COFF64 | _ELF | _MachO:
host = "aarch64-unknown-linux-gnu"
condition = "defined(__aarch64__) && defined(__linux__)"
# -mno-outline-atomics: Keep intrinsics from being emitted.
args = ["-fpic", "-mno-outline-atomics", "-fno-plt"]
args = ["-fpic", "-mno-outline-atomics"]
optimizer = _optimizers.OptimizerAArch64
target = _ELF(
host, condition, args=args, optimizer=optimizer, frame_pointers=True
Expand Down Expand Up @@ -622,7 +622,7 @@ def get_target(host: str) -> _COFF32 | _COFF64 | _ELF | _MachO:
elif re.fullmatch(r"x86_64-.*-linux-gnu", host):
host = "x86_64-unknown-linux-gnu"
condition = "defined(__x86_64__) && defined(__linux__)"
args = ["-fno-pic", "-mcmodel=medium", "-mlarge-data-threshold=0", "-fno-plt"]
args = ["-fno-pic", "-mcmodel=medium", "-mlarge-data-threshold=0"]
optimizer = _optimizers.OptimizerX86
target = _ELF(
host, condition, args=args, optimizer=optimizer, frame_pointers=True
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