cac8bdb56c
Call graph section emitted by LLVM was named `.callgraph`. Renaming it to `.llvm.callgraph`.
19 lines
2.3 KiB
Markdown
19 lines
2.3 KiB
Markdown
# .llvm.callgraph Section Layout
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The `.llvm.callgraph` section is used to store call graph information for each function. The section contains a series of records, with each record corresponding to a single function.
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## Per Function Record Layout
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Each record in the `.llvm.callgraph` section has the following binary layout:
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| Field | Type | Size (bits) | Description |
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| -------------------------------------- | ------------- | ----------- | ------------------------------------------------------------------------------------------------------- |
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| Format Version | `uint8_t` | 8 | The version of the record format. The current version is 0. |
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| Flags | `uint8_t` | 8 | A bitfield where: Bit 0 is set if the function is a potential indirect call target; Bit 1 is set if there are direct callees; Bit 2 is set if there are indirect callees. The remaining 5 bits are reserved. |
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| Function Entry PC | `uintptr_t` | 32/64 | The address of the function's entry point. |
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| Function Type ID | `uint64_t` | 64 | The type ID of the function. This field is non-zero if the function is a potential indirect call target and its type is known. |
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| Number of Unique Direct Callees | `ULEB128` | Variable | The number of unique direct call destinations from this function. This field is only present if there is at least one direct callee. |
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| Direct Callees Array | `uintptr_t[]` | Variable | An array of unique direct callee entry point addresses. This field is only present if there is at least one direct callee. |
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| Number of Unique Indirect Target Type IDs| `ULEB128` | Variable | The number of unique indirect call target type IDs. This field is only present if there is at least one indirect target type ID. |
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| Indirect Target Type IDs Array | `uint64_t[]` | Variable | An array of unique indirect call target type IDs. This field is only present if there is at least one indirect target type ID. |
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